Nat Commun , IF:14.919 , 2021 Aug , V12 (1) : P4713 doi: 10.1038/s41467-021-25001-y
Natural variation in a type-A response regulator confers maize chilling tolerance.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China.; State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China. yangshuhua@cau.edu.cn.
Maize (Zea mays L.) is a cold-sensitive species that often faces chilling stress, which adversely affects growth and reproduction. However, the genetic basis of low-temperature adaptation in maize remains unclear. Here, we demonstrate that natural variation in the type-A Response Regulator 1 (ZmRR1) gene leads to differences in chilling tolerance among maize inbred lines. Association analysis reveals that InDel-35 of ZmRR1, encoding a protein harboring a mitogen-activated protein kinase (MPK) phosphorylation residue, is strongly associated with chilling tolerance. ZmMPK8, a negative regulator of chilling tolerance, interacts with and phosphorylates ZmRR1 at Ser15. The deletion of a 45-bp region of ZmRR1 harboring Ser15 inhibits its degradation via the 26 S proteasome pathway by preventing its phosphorylation by ZmMPK8. Transcriptome analysis indicates that ZmRR1 positively regulates the expression of ZmDREB1 and Cellulose synthase (CesA) genes to enhance chilling tolerance. Our findings thus provide a potential genetic resource for improving chilling tolerance in maize.
PMID: 34354054
Plant Cell , IF:11.277 , 2021 Aug doi: 10.1093/plcell/koab215
The CRY2-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 200032 Shanghai, China.
Light and temperature are two key environmental factors that coordinately regulate plant growth and development. Although the mechanisms that integrate signaling mediated by cold and red light have been unraveled, the roles of the blue light photoreceptors cryptochromes in plant responses to cold remain unclear. In this study, we demonstrate that the CRYPTOCHROME2 (CRY2)-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis thaliana. We show that phosphorylated forms of CRY2 induced by blue light are stabilized by cold stress and that cold-stabilized CRY2 competes with the transcription factor HY5 to attenuate the HY5-COP1 interaction, thereby allowing HY5 to accumulate at cold temperatures. Furthermore, our data demonstrate that B-BOX DOMAIN PROTEIN7 (BBX7) and BBX8 function as direct HY5 targets that positively regulate freezing tolerance by modulating the expression of a set of cold-responsive genes, which mainly occurs independently of the C-REPEAT-BINDING FACTOR pathway. Our study uncovers a mechanistic framework by which CRY2-mediated blue-light signaling enhances freezing tolerance, shedding light on the molecular mechanisms underlying the crosstalk between cold and light signaling pathways in plants.
PMID: 34427646
Plant Cell , IF:11.277 , 2021 Aug , V33 (7) : P2431-2453 doi: 10.1093/plcell/koab122
Synaptotagmins at the endoplasmic reticulum-plasma membrane contact sites maintain diacylglycerol homeostasis during abiotic stress.
Departamento de Biologia Molecular y Bioquimica, Instituto de Hortofruticultura Subtropical y Mediterranea "La Mayora", Universidad de Malaga-Consejo Superior de Investigaciones Cientificas (IHSM-UMA-CSIC), Universidad de Malaga, Malaga 12907, Spain.; Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai 201602, China.; Plant Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium.; VIB Center for Plant Systems Biology, Ghent 9052, Belgium.; Departamento de Biotecnologia Microbiana y de Plantas, Centro de Investigaciones Biologicas Margarita Salas-CSIC, Madrid, 28040, Spain.; Departamento de Cristalografia y Biologia Estructural, Instituto de Quimica Fisica "Rocasolano", Consejo Superior de Investigaciones Cientificas, Madrid, 28006, Spain.; College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.; Institute of Science and Technology (IST), Klosterneuburg, 3400, Austria.; Department of Botany, The University of British Columbia, Vancouver, Canada, BC V6T 1Z4.
Endoplasmic reticulum-plasma membrane contact sites (ER-PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER-PM protein tether synaptotagmin1 (SYT1) exhibit decreased PM integrity under multiple abiotic stresses, such as freezing, high salt, osmotic stress, and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER-PM tether that also functions in maintaining PM integrity. The ER-PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild-type while the levels of most glycerolipid species remain unchanged. In addition, the SYT1-green fluorescent protein fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.
PMID: 33944955
Food Chem , IF:7.514 , 2021 Aug , V353 : P129482 doi: 10.1016/j.foodchem.2021.129482
Effects of exogenous methyl jasmonate on quality and preservation of postharvest fruits: A review.
School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China.; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 226019, People's Republic of China. Electronic address: fqliu20011@sina.com.; School of Life Sciences, Nantong University, Nantong 226019, People's Republic of China. Electronic address: pedro@ntu.edu.cn.
Methyl jasmonate (MeJA) is a volatile hormone involved in a number of plant processes, acting as a signal in response to external stresses and modulating the biosynthesis of other phytohormones. Here, we are reviewing for the first time all reports related to the effects of exogenous MeJA on postharvest fruits. Application of MeJA during preharvest and postharvest stages has been demonstrated to enhance fruit antioxidant capacity and phenolics content, which in turn extended fruit shelf-life, enhanced fruit quality and reduced chilling injury. The postharvest application of MeJA has been reported to alter volatiles pattern and to enhance the innate disease resistance of postharvest fruits against pathogenic fungi. The results obtained using different treatment conditions, such as temperature, storage time and concentration, have been highlighted and compared along the manuscript in order to provide new insights on the applicability of MeJA for enhancing postharvest fruit quality and preservation.
PMID: 33725541
Free Radic Biol Med , IF:7.376 , 2021 Aug , V172 : P286-297 doi: 10.1016/j.freeradbiomed.2021.06.011
Cold plasma seed treatment improves chilling resistance of tomato plants through hydrogen peroxide and abscisic acid signaling pathway.
State Key Laboratory of Crop Biology / Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture / Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong / College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China.; China Agricultural University, Beijing, 100083, China.; State Key Laboratory of Crop Biology / Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture / Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong / College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: gongbiao@sdau.edu.cn.
How to develop a simple and economic approach to improve plant cold stress tolerance is an important scientific problem. With the hope that we explored the effect and metabolism of cold plasma (CP) seed treatment on the chilling tolerance in tomato plants. 75 W CP seed treatment showed the best mitigative effect on cold-induced injury of tomato seedlings, as evidenced by the higher maximum photochemical efficiency of PSII (Fv/Fm), lower ion leakage and chilling injury index. Moreover, the results showed that CP-induced chilling tolerance was related to the hydrogen peroxide (H2O2) mediated by respiratory burst oxidase homologue 1 (RBOH1), which was proved by the decrease low temperature tolerance observed in RBOH1 silence or chemical scavenging of H2O2 seedlings. Furthermore, RBOH1-mediated H2O2 acted as the downstream signaling of CP treatment to enhance the levels of abscisic acid (ABA) by increasing the transcript of 9-cis-epoxycarotenoid dioxygenase 1 (NCED1). Mutation of NCED1 completely abolished CP-induced cold resistance. Genetic evidence showed that H2O2 and ABA were positive regulators of cold stress tolerance. Thus, CP-induced H2O2 and ABA cascade signal up-regulated the regulatory genes (ICE1 and CBF1) of cold acclimation, which increased the osmotic adjustment substances (proline and soluble sugar) accumulation and antioxidant enzymes (SOD, APX and CAT) activities. Our results indicate that H2O2 and ABA signals are involved in conferring cold stress tolerance induced by CP seed treatment in tomato plants.
PMID: 34139310
J Integr Plant Biol , IF:7.061 , 2021 Aug doi: 10.1111/jipb.13161
The direct targets of CBFs: in cold stress response and beyond.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Cold acclimation in Arabidopsis thaliana triggers a significant transcriptional reprogramming altering the expression patterns of thousands of cold-responsive (COR) genes. Essential to this process is the C-repeat binding factor (CBF)-dependent pathway, involving the activity of AP2/ERF (APETALA2/ethylene-responsive factor)-type CBF transcription factors required for plant cold acclimation. In this study, we performed chromatin immunoprecipitation assays followed by deep sequencing (ChIP-seq) to determine the genome-wide binding sites of the CBF transcription factors. Cold-induced CBF proteins specifically bind to the conserved C-repeat (CRT)/dehydration-responsive elements (CRT/DRE; G/ACCGAC) of their target genes. A Gene Ontology enrichment analysis showed that 1,012 genes are targeted by all three CBFs. Combined with a transcriptional analysis of the cbf1,2,3 triple mutant, we define 146 CBF regulons as direct CBF targets. In addition, the CBF-target genes are significantly enriched in functions associated with hormone, light, and circadian rhythm signaling, suggesting that the CBFs act as key integrators of endogenous and external environmental cues. Our findings not only define the genome-wide binding patterns of the CBFs during the early cold response, but also provide insights into the role of the CBFs in regulating multiple biological processes of plants. This article is protected by copyright. All rights reserved.
PMID: 34379362
J Exp Bot , IF:6.992 , 2021 Aug doi: 10.1093/jxb/erab392
OsATL38 mediates mono-ubiquitination of the 14-3-3 protein OsGF14d and negatively regulates the cold stress response in rice.
Department of Systems Biology and Division of Life Science, Yonsei University, Seoul, Korea.; Institute of Life Science and Biotechnology, Yonsei University, Seoul, Korea.
One of the major regulatory pathways that permits plants to convert an external stimulus into an internal cellular response within a short period of time is the ubiquitination pathway. In this study, OsATL38 was identified as a low temperature-induced gene that encodes a rice homolog of Arabidopsis Toxicos en Levadura RING-type E3 ubiquitin (Ub) ligase, which was predominantly localized to the plasma membrane. OsATL38-overexpressing transgenic rice plants exhibited decreased tolerance to cold stress as compared to wild-type rice plants. In contrast, RNAi-mediated OsATL38 knockdown transgenic progeny exhibited markedly increased tolerance to cold stress relative to that of wild-type plants, which indicated a negative role of OsATL38 in response to cold stress. Yeast two-hybrid, in vitro pull-down, and co-IP assays revealed that OsATL38 physically interacted with OsGF14d, a rice 14-3-3 protein. An in vivo target ubiquitination assay indicated that OsGF14d was mono-ubiquitinated by OsATL38. The osgf14d knockout mutant plants were more sensitive to cold stress than wild-type rice plants, indicating that OsGF14d is a positive factor in the response to cold stress. These results suggested that the RING E3 Ub ligase OsATL38 negatively regulates the cold stress response in rice via mono-ubiquitination of OsGF14d 14-3-3 protein.
PMID: 34436579
Int J Biol Macromol , IF:6.953 , 2021 Aug , V188 : P924-931 doi: 10.1016/j.ijbiomac.2021.07.186
Characterization and functional analysis of Cshsp19.0 encoding a small heat shock protein in Chilo suppressalis (Walker).
College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China.; Plant Protection and Quarantine Station of Jiangsu Province, Nanjing 210000, China.; College of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education, Yangzhou University, Yangzhou, China. Electronic address: yzdu@yzu.edu.cn.
Small heat shock proteins (sHSPs) function as ATP-independent chaperones that preserve cellular proteostasis under stressful conditions. In this study, Cshsp19.0, which encodes a new small heat shock protein, was isolated and characterized from Chilo suppressalis (Walker) to better understand the contribution of sHSPs to insect development and stress tolerance. The full-length Cshsp19.0 cDNA was 697 bp and encoded a 19.0 kDa protein with an isoelectric point of 5.95. Phylogenetic analysis and amino acid alignments indicated that Cshsp19.0 is a member of the sHSP family. Cshsp19.0 was expressed at maximal levels in foreguts and showed the least amount of expression in fat bodies. Expression analysis in different developmental stages of C. suppressalis revealed that Cshsp19.0 was most highly expressed in 1st instar larvae. Furthermore, Cshsp19.0 was upregulated when insects were exposed to heat and cold stress for a 2-h period. There were significant differences in the male and female pupae in response to humidity; Cshsp19.0 expression increased in male pupae as RH increased, whereas the inverse pattern was observed in female pupae. Larvae exhibited a lower rate of survival when Cshsp19.0 was silenced by a nanomaterial-promoted RNAi method. The results confirm that Cshsp19.0 functions to increase environmental stress tolerance and regulates physiological activities in C. suppressalis.
PMID: 34352319
Plant J , IF:6.417 , 2021 Aug doi: 10.1111/tpj.15465
ERF108 from Poncirus trifoliata (L.) Raf. functions in cold tolerance by modulating raffinose synthesis through transcriptional regulation of PtrRafS.
Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Ethylene-responsive factors (ERFs) are plant-specific transcription factors involved in cold stress response, and raffinose is known to accumulate in plants exposed to cold. However, it remains elusive whether ERFs function in cold tolerance by modulating raffinose synthesis. Here, we identified a cold-responsive PtrERF108 from trifoliate orange (Poncirus trifoliata (L.) Raf.), a cold-tolerant plant closely related to citrus. PtrERF108 is localized in the nucleus and has transcriptional activation activity. Overexpression of PtrERF108 conferred enhanced cold tolerance of transgenic lemon, whereas virus-induced gene silencing (VIGS)-mediated knockdown of PtrERF108 in trifoliate orange greatly elevated cold sensitivity. Transcriptome profiling showed that PtrERF108 overexpression caused extensive reprogramming of genes associated with signaling transduction, physiological processes, and metabolic pathways. Among them, a raffinose synthase (RafS)-encoding gene, PtrRafS, was confirmed as a direct target of PtrERF108. RafS activity and raffinose content were significantly increased in PtrERF108-overexpressing transgenic plants, but prominently decreased in the VIGS plants under cold conditions. Meanwhile, exogenous replenishment of raffinose could recover the cold tolerance of PtrERF108-silenced plants, whereas VIGS-mediated knockdown of PtrRafS resulted in cold-sensitive phenotype. Taken together, the current results demonstrate that PtrERF108 plays a positive role in cold tolerance by modulation of raffinose synthesis via regulating PtrRafS. Our findings reveal a new transcriptional module composed of ERF108-RafS underlying cold-induced raffinose accumulation in plants.
PMID: 34398993
Antioxidants (Basel) , IF:6.312 , 2021 Aug , V10 (8) doi: 10.3390/antiox10081287
Demyristoylation of the Cytoplasmic Redox Protein Trx-h2 Is Critical for Inducing a Rapid Cold Stress Response in Plants.
Division of Applied Life Science (BK21+) and PMBBRC, Gyeongsang National University, Jinju 52828, Korea.; College of Pharmacy, Gyeongsang National University, Jinju 52828, Korea.; Plant Systems Engineering Research Center, KRIBB, Daejeon 34141, Korea.; Department of Biomedical Science & Engineering, Konkuk University, Seoul 05029, Korea.
In Arabidopsis, the cytosolic redox protein thioredoxin h2 (Trx-h2) is anchored to the cytoplasmic endomembrane through the myristoylated second glycine residue (Gly(2)). However, under cold stress, the cytosolic Trx-h2 is rapidly translocated to the nucleus, where it interacts with and reduces the cold-responsive C-repeat-binding factors (CBFs), thus activating cold-responsive (COR) genes. In this study, we investigated the significance of fatty acid modification of Trx-h2 under cold conditions by generating transgenic Arabidopsis lines in the trx-h2 mutant background, overexpressing Trx-h2 (Trx-h2(OE)/trx-h2) and its point mutation variant Trx-h2(G/A) [Trx-h2(G/A)(OE)/trx-h2], in which the Gly(2) was replaced by alanine (Ala). Due to the lack of Gly(2), Trx-h2(G/A) was incapable of myristoylation, and a part of Trx-h2(G/A) localized to the nucleus even under warm temperature. As no time is spent on the demyristoylation and subsequent nuclear translocation of Trx-h2(G/A) under a cold snap, the ability of Trx-h2(G/A) to protect plants from cold stress was greater than that of Trx-h2. Additionally, COR genes were up-regulated earlier in Trx-h2(G/A)2(OE)/trx-h2 plants than in Trx-h2(OE)/trx-h2 plants under cold stress. Consequently, Trx-h2(G/A)2(OE)/trx-h2 plants showed greater cold tolerance than Col-0 (wild type) and Trx-h2(OE)/trx-h2 plants. Overall, our results clearly demonstrate the significance of the demyristoylation of Trx-h2 in enhancing plant cold/freezing tolerance.
PMID: 34439534
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168843
Role of Reactive Oxygen Species and Hormones in Plant Responses to Temperature Changes.
Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Temperature stress is one of the major abiotic stresses that adversely affect agricultural productivity worldwide. Temperatures beyond a plant's physiological optimum can trigger significant physiological and biochemical perturbations, reducing plant growth and tolerance to stress. Improving a plant's tolerance to these temperature fluctuations requires a deep understanding of its responses to environmental change. To adapt to temperature fluctuations, plants tailor their acclimatory signal transduction events, and specifically, cellular redox state, that are governed by plant hormones, reactive oxygen species (ROS) regulatory systems, and other molecular components. The role of ROS in plants as important signaling molecules during stress acclimation has recently been established. Here, hormone-triggered ROS produced by NADPH oxidases, feedback regulation, and integrated signaling events during temperature stress activate stress-response pathways and induce acclimation or defense mechanisms. At the other extreme, excess ROS accumulation, following temperature-induced oxidative stress, can have negative consequences on plant growth and stress acclimation. The excessive ROS is regulated by the ROS scavenging system, which subsequently promotes plant tolerance. All these signaling events, including crosstalk between hormones and ROS, modify the plant's transcriptomic, metabolomic, and biochemical states and promote plant acclimation, tolerance, and survival. Here, we provide a comprehensive review of the ROS, hormones, and their joint role in shaping a plant's responses to high and low temperatures, and we conclude by outlining hormone/ROS-regulated plant responsive strategies for developing stress-tolerant crops to combat temperature changes.
PMID: 34445546
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168628
Melatonin Application Modifies Antioxidant Defense and Induces Endoreplication in Maize Seeds Exposed to Chilling Stress.
Department of Plant Ecophisiology, Faculty of Biology and Environmental Protection, University of Lodz, 90237 Lodz, Poland.; Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Lodz, 90237 Lodz, Poland.
The aim of the study was to demonstrate the biostimulating effect of exogenous melatonin (MEL) applied to seeds via hydroconditioning. It was indicated that only well-chosen application technique and MEL dose guarantees success concerning seed germination and young seedlings growth under stress conditions. For maize seed, 50 muM of MEL appeared to be the optimal dose. It improved seed germination and embryonic axes growth especially during chilling stress (5 degrees C/14 days) and during regeneration after its subsided. Unfortunately, MEL overdosing lowered IAA level in dry seeds and could disrupt the ROS-dependent signal transduction pathways. Very effective antioxidant MEL action was confirmed by low level of protein oxidative damage and smaller quantity of lipid oxidation products in embryonic axes isolated from seeds pre-treated with MEL and then exposed to cold. The stimulatory effects of MEL on antioxidant enzymes: SOD, APX and GSH-PX and on GST-a detoxifying enzyme, was also demonstrated. It was indicated for the first time, that MEL induced defence strategies against stress at the cytological level, as appearing endoreplication in embryonic axes cells even in the seeds germinating under optimal conditions (preventive action), but very intensively in those germinating under chilling stress conditions (intervention action), and after stress removal, to improve regeneration.
PMID: 34445334
Genomics , IF:5.736 , 2021 Aug , V113 (6) : P3476-3486 doi: 10.1016/j.ygeno.2021.08.006
Epigenetic differences in an identical genetic background modulate alternative splicing in A. thaliana.
School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK; Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK. Electronic address: ChaudharyS6@cardiff.ac.uk.; School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK; Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK.; School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury CT1 1QU, UK. Electronic address: naeem.syed@canterbury.ac.uk.
How stable and temperature-dependent variations in DNA methylation and nucleosome occupancy influence alternative splicing (AS) remains poorly understood in plants. To answer this, we generated transcriptome, whole-genome bisulfite, and MNase sequencing data for an epigenetic Recombinant Inbred Line (epiRIL) of A. thaliana at normal and cold temperature. For comparative analysis, the same data sets for the parental ecotype Columbia (Col-0) were also generated, whereas for DNA methylation, previously published high confidence methylation profiles of Col-0 were used. Significant epigenetic differences in an identical genetic background were observed between Col-0 and epiRIL lines under normal and cold temperatures. Our transcriptome data revealed that differential DNA methylation and nucleosome occupancy modulate expression levels of many genes and AS in response to cold. Collectively, DNA methylation and nucleosome levels exhibit characteristic patterns around intron-exon boundaries at normal and cold conditions, and any perturbation in them, in an identical genetic background is sufficient to modulate AS in Arabidopsis.
PMID: 34391867
Physiol Plant , IF:4.5 , 2021 Aug doi: 10.1111/ppl.13522
CGFS-type glutaredoxin mutations reduce tolerance to multiple abiotic stresses in tomato.
Department of Horticulture and Natural Resources, Kansas State University, Manhattan, Kansas, USA.; Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Sessile organisms such as plants have adopted diverse reactive oxygen species (ROS) scavenging mechanisms to mitigate damage under abiotic stress conditions. Though CGFS-type glutaredoxin (GRX) genes are important regulators of ROS homeostasis, each of their functions in crop plants have not yet been well understood. We performed a targeted mutagenesis analysis of four CGFS-type GRXs (SlGRXS14, SlGRXS15, SlGRXS16, and SlGRXS17) in tomato plants (Solanum lycopersicum) using a multiplex clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system and found that Slgrxs mutants were more sensitive to various abiotic stresses compared with the wild-type tomatoes. Slgrxs15 mutants were embryonic lethal. Single, double, and triple combinations of Slgrxs14, 16, and 17 mutants were examined under heat, chilling, drought, heavy metal toxicity, nutrient deficiency, and short photoperiod stresses. Slgrxs14 and 17 mutants showed hypersensitivity to almost all stresses while Slgrxs16 mutants were affected by chilling stress and showed milder sensitivity to other stresses. Additionally, Slgrxs14 and 17 mutants showed delayed flowering time. Our results indicate that the CGFS-type SlGRXs have specific roles against abiotic stresses, providing valuable resources to develop tomato and, possibly, other crop species that are tolerant to multiple abiotic stresses by genetic engineering.
PMID: 34392538
Sci Rep , IF:4.379 , 2021 Aug , V11 (1) : P16574 doi: 10.1038/s41598-021-96102-3
Ectopic expression of a novel cold-resistance protein 1 from Brassica oleracea promotes tolerance to chilling stress in transgenic tomato.
Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Kashmir, 190 006, India.; Department of Biotechnology, University of Kashmir, Srinagar, India.; Plant Molecular Biology Lab, Department of Botany, University of Kashmir, Srinagar, Kashmir, 190 006, India. riffatminhaj@kashmiruniversity.ac.in.
Cold stress is considered as one of the major environmental factors that adversely affects the plant growth and distribution. Therefore, there arises an immediate need to cultivate effective strategies aimed at developing stress-tolerant crops that would boost the production and minimise the risks associated with cold stress. In this study, a novel cold-responsive protein1 (BoCRP1) isolated from Brassica oleracea was ectopically expressed in a cold susceptible tomato genotype Shalimar 1 and its function was investigated in response to chilling stress. BoCRP1 was constitutively expressed in all the tissues of B. oleracea including leaf, root and stem. However, its expression was found to be significantly increased in response to cold stress. Moreover, transgenic tomato plants expressing BoCRP1 exhibited increased tolerance to chilling stress (4 degrees C) with an overall improved rate of seed germination, increased root length, reduced membrane damage and increased accumulation of osmoprotectants. Furthermore, we observed increased transcript levels of stress responsive genes and enhanced accumulation of reactive oxygen species scavenging enzymes in transgenic plants on exposure to chilling stress. Taken together, these results strongly suggest that BoCRP1 is a promising candidate gene to improve the cold stress tolerance in tomato.
PMID: 34400729
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P369 doi: 10.1186/s12870-021-03157-5
Enhancement of plant cold tolerance by soybean RCC1 family gene GmTCF1a.
Shijiazhuang Academy of Agricultural and Forestry Sciences, 479 Shenglibei Street, Shijiazhuang, 050041, Hebei, China.; National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.; National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China. htji@mail.hzau.edu.cn.
BACKGROUND: Low temperature severely limits the growth, yield, and geographic distributions of soybean. Soybean plants respond to cold stress by reprogramming the expression of a series of cold-responsive genes. However, the intrinsic mechanism underlying cold-stress tolerance in soybean remains unclear. A. thaliana tolerant to chilling and freezing 1 (AtTCF1) is a regulator of chromosome condensation 1 (RCC1) family protein and regulates freezing tolerance through an independent C-repeat binding transcription factor (CBF) signaling pathway. RESULTS: In this study, we identified a homologous gene of AtTCF1 in soybean (named GmTCF1a), which mediates plant tolerance to low temperature. Like AtTCF1, GmTCF1a contains five RCC1 domains and is located in the nucleus. GmTCF1a is strongly and specifically induced by cold stress. Interestingly, ectopic overexpression of GmTCF1a in Arabidopsis greatly increased plant survival rate and decreased electrolyte leakage under freezing stress. A cold-responsive gene, COR15a, was highly induced in the GmTCF1a-overexpressing transgenic lines. CONCLUSIONS: GmTCF1a responded specifically to cold stress, and ectopic expression of GmTCF1a enhanced cold tolerance and upregulated COR15a levels. These results indicate that GmTCF1a positively regulates cold tolerance in soybean and may provide novel insights into genetic improvement of cold tolerance in crops.
PMID: 34384381
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P365 doi: 10.1186/s12870-021-03152-w
Full-length transcriptome profiling reveals insight into the cold response of two kiwifruit genotypes (A. arguta) with contrasting freezing tolerances.
Key Laboratory for Fruit Tree Growth, Development and Quality Control, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.; Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China. chungen@mail.hzau.edu.cn.; Key Laboratory for Fruit Tree Growth, Development and Quality Control, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China. fangjinbao@caas.cn.
BACKGROUND: Kiwifruit (Actinidia Lindl.) is considered an important fruit species worldwide. Due to its temperate origin, this species is highly vulnerable to freezing injury while under low-temperature stress. To obtain further knowledge of the mechanism underlying freezing tolerance, we carried out a hybrid transcriptome analysis of two A. arguta (Actinidi arguta) genotypes, KL and RB, whose freezing tolerance is high and low, respectively. Both genotypes were subjected to - 25 degrees C for 0 h, 1 h, and 4 h. RESULTS: SMRT (single-molecule real-time) RNA-seq data were assembled using the de novo method, producing 24,306 unigenes with an N50 value of 1834 bp. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DEGs showed that they were involved in the 'starch and sucrose metabolism', the 'mitogen-activated protein kinase (MAPK) signaling pathway', the 'phosphatidylinositol signaling system', the 'inositol phosphate metabolism', and the 'plant hormone signal transduction'. In particular, for 'starch and sucrose metabolism', we identified 3 key genes involved in cellulose degradation, trehalose synthesis, and starch degradation processes. Moreover, the activities of beta-GC (beta-glucosidase), TPS (trehalose-6-phosphate synthase), and BAM (beta-amylase), encoded by the abovementioned 3 key genes, were enhanced by cold stress. Three transcription factors (TFs) belonging to the AP2/ERF, bHLH (basic helix-loop-helix), and MYB families were involved in the low-temperature response. Furthermore, weighted gene coexpression network analysis (WGCNA) indicated that beta-GC, TPS5, and BAM3.1 were the key genes involved in the cold response and were highly coexpressed together with the CBF3, MYC2, and MYB44 genes. CONCLUSIONS: Cold stress led various changes in kiwifruit, the 'phosphatidylinositol signaling system', 'inositol phosphate metabolism', 'MAPK signaling pathway', 'plant hormone signal transduction', and 'starch and sucrose metabolism' processes were significantly affected by low temperature. Moreover, starch and sucrose metabolism may be the key pathway for tolerant kiwifruit to resist low temperature damages. These results increase our understanding of the complex mechanisms involved in the freezing tolerance of kiwifruit under cold stress and reveal a series of candidate genes for use in breeding new cultivars with enhanced freezing tolerance.
PMID: 34380415
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P361 doi: 10.1186/s12870-021-03021-6
Metabolic activities and molecular investigations of the ameliorative impact of some growth biostimulators on chilling-stressed coriander (Coriandrum sativum L.) plant.
Department of Botany, Faculty of Science, Ain Shams University, Cairo, 11355, Egypt.; Department of Natural Products, National Center for Radiation Research and Technology, Atomic Energy Authority, P.O. 29, Cairo, Nasr City, Egypt.; Department of Botany, Faculty of Science, Ain Shams University, Cairo, 11355, Egypt. m.shehata@sci.asu.edu.eg.
BACKGROUND: Priming of seed prior chilling is regarded as one of the methods to promote seeds germination, whole plant growth, and yield components. The application of biostimulants was reported as beneficial for protecting many plants from biotic or abiotic stresses. Their value was as important to be involved in improving the growth parameters of plants. Also, they were practiced in the regulation of various metabolic pathways to enhance acclimation and tolerance in coriander against chilling stress. To our knowledge, little is deciphered about the molecular mechanisms underpinning the ameliorative impact of biostimulants in the context of understanding the link and overlap between improved morphological characters, induced metabolic processes, and upregulated gene expression. In this study, the ameliorative effect(s) of potassium silicate, HA, and gamma radiation on acclimation of coriander to tolerate chilling stress was evaluated by integrating the data of growth, yield, physiological and molecular aspects. RESULTS: Plant growth, yield components, and metabolic activities were generally diminished in chilling-stressed coriander plants. On the other hand, levels of ABA and soluble sugars were increased. Alleviation treatment by humic acid, followed by silicate and gamma irradiation, has notably promoted plant growth parameters and yield components in chilling-stressed coriander plants. This improvement was concomitant with a significant increase in phytohormones, photosynthetic pigments, carbohydrate contents, antioxidants defense system, and induction of large subunit of RuBisCO enzyme production. The assembly of Toc complex subunits was maintained, and even their expression was stimulated (especially Toc75 and Toc 34) upon alleviation of the chilling stress by applied biostimulators. Collectively, humic acid was the best the element to alleviate the adverse effects of chilling stress on growth and productivity of coriander. CONCLUSIONS: It could be suggested that the inducing effect of the pretreatments on hormonal balance triggered an increase in IAA + GA3/ABA hormonal ratio. This ratio could be linked and engaged with the protection of cellular metabolic activities from chilling injury against the whole plant life cycle. Therefore, it was speculated that seed priming in humic acid is a powerful technique that can benefit the chilled along with non-chilled plants and sustain the economic importance of coriander plant productivity.
PMID: 34364372
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P377 doi: 10.1186/s12870-021-03158-4
Differences in lipid homeostasis and membrane lipid unsaturation confer differential tolerance to low temperatures in two Cycas species.
Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, 650233, Yunnan, China.; Administration Bureau of Panzhihua Cycas National Nature Reserve, Panzhihua, 617000, Sichuan, China.; Key Laboratory of State Forestry and Grassland Administration for Biodiversity Conservation in Southwest China, Southwest Forestry University, Kunming, 650233, Yunnan, China. 565180277@qq.com.; Administration Bureau of Panzhihua Cycas National Nature Reserve, Panzhihua, 617000, Sichuan, China. flashingzyl@163.com.
BACKGROUND: C. panzhihuaensis is more tolerant to freezing than C. bifida but the mechanisms underlying the different freezing tolerance are unclear. Photosynthesis is one of the most temperature-sensitive processes. Lipids play important roles in membrane structure, signal transduction and energy storage, which are closely related to the stress responses of plants. In this study, the chlorophyll fluorescence parameters and lipid profiles of the two species were characterized to explore the changes in photosynthetic activity and lipid metabolism following low-temperature exposure and subsequent recovery. RESULTS: Photosynthetic activity significantly decreased in C. bifida with the decrease of temperatures and reached zero after recovery. Photosynthetic activity, however, was little affected in C. panzhihuaensis. The lipid composition of C. bifida was more affected by cold and freezing treatments than C. panzhihuaensis. Compared with the control, the proportions of all the lipid categories recovered to the original level in C. panzhihuaensis, but the proportions of most lipid categories changed significantly in C. bifida after 3 d of recovery. In particular, the glycerophospholipids and prenol lipids degraded severely during the recovery period of C. bifida. Changes in acyl chain length and double bond index (DBI) occurred in more lipid classes immediately after low-temperature exposure in C. panzhihuaensis compare with those in C. bifida. DBI of the total main membrane lipids of C. panzhihuaensis was significantly higher than that of C. bifida following all temperature treatments. CONCLUSIONS: The results of chlorophyll fluorescence parameters confirmed that the freezing tolerance of C. panzhihuaensis was greater than that of C. bifida. The lipid metabolism of the two species had differential responses to low temperatures. The homeostasis and plastic adjustment of lipid metabolism and the higher level of DBI of the main membrane lipids may contribute to the greater tolerance of C. panzhihuaensis to low temperatures.
PMID: 34399687
Planta , IF:4.116 , 2021 Aug , V254 (3) : P50 doi: 10.1007/s00425-021-03696-z
Production of purple Ma bamboo (Dendrocalamus latiflorus Munro) with enhanced drought and cold stress tolerance by engineering anthocyanin biosynthesis.
Basic Forestry and Proteomics Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Fujian Agriculture and Forestry University, Fuzhou, China.; State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, China.; The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, College of Life Sciences, Shandong University, Jinan, Shandong, China.; Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, 90095, USA.; Basic Forestry and Proteomics Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China. zhuqiang@fafu.edu.cn.
MAIN CONCLUSION: Overexpression of the leaf color (Lc) gene in Ma bamboo substantially increased the accumulation level of anthocyanin, and improved plant tolerance to cold and drought stresses, probably due to the increased antioxidant capacity. Most bamboos, including Ma bamboo (Dendrocalamus latiflorus Munro), are naturally evergreen and sensitive to cold and drought stresses, while it's nearly impossible to make improvements through conventual breeding due to their long and irregular flowering habit. Moreover, few studies have reported bamboo germplasm innovation through genetic engineering as bamboo genetic transformation remains difficult. In this study, we have upregulated anthocyanin biosynthesis in Ma bamboo, to generate non-green Ma bamboo with increased abiotic stress tolerance. By overexpressing the maize Lc gene, a bHLH transcription activator involved in the anthocyanin biosynthesis in Ma bamboo, we generated purple bamboos with increased anthocyanin levels including cyanidin-3-O-rutinoside, peonidin 3-O-rutinoside, and an unknown cyanidin pentaglycoside derivative. The expression levels of 9 anthocyanin biosynthesis genes were up-regulated. Overexpression of the Lc gene improved the plant tolerance to cold and drought stress, probably due to increased antioxidant capacity. The levels of the cold- and drought-related phytohormone jasmonic acid in the transgenic plants were also enhanced, which may also contribute to the plant stress-tolerant phenotypes. High anthocyanin accumulation level did not affect plant growth. Transcriptomic analysis showed higher expressions of genes involved in the flavonoid pathway in Lc transgenic bamboos compared with those in wild-type ones. The anthocyanin-rich bamboos generated here provide an example of ornamental and multiple agronomic trait improvements by genetic engineering in this important grass species.
PMID: 34386845
Planta , IF:4.116 , 2021 Aug , V254 (3) : P46 doi: 10.1007/s00425-021-03694-1
What if the cold days return? Epigenetic mechanisms in plants to cold tolerance.
Instituto de Ciencias Biologicas, Universidad de Talca, Campus Talca, Talca, Chile.; Instituto de Ciencias Biologicas, Universidad de Talca, Campus Talca, Talca, Chile. marco.molina@utalca.cl.; Centro de Estudios Avanzados en Zonas Aridas (CEAZA), Universidad Catolica del Norte, Coquimbo, Chile. marco.molina@utalca.cl.; Centro de Investigaciones y Estudios Avanzados del Maule (CIEAM), Universidad Catolica del Maule, Talca, Chile. marco.molina@utalca.cl.
MAIN CONCLUSION: The epigenetic could be an important, but seldom assessed, mechanisms in plants inhabiting cold ecosystems. Thus, this review could help to fill a gap in the current literature. Low temperatures are one of the most critical environmental conditions that negatively affect the growth, development, and geographic distribution of plants. Exposure to low temperatures results in a suit of physiological, biochemical and molecular modifications through the reprogramming of the expression of genes and transcription factors. Scientific evidence shows that the average annual temperature has increased in recent years worldwide, with cold ecosystems (polar and high mountain) being among the most sensitive to these changes. However, scientific evidence also indicates that there would be specific events of low temperatures, due it is highly relevant to know the capacity for adaptation, regulation and epigenetic memory in the face of these events, by plants. Epigenetic regulation has been described to play an important role in the face of environmental stimuli, especially in response to abiotic stress. Several studies on epigenetic mechanisms have focused on responses to stress as drought and/or salinity; however, there is a gap in the current literature considering those related to low temperatures. In this review, we focus on systematizing the information published to date, related to the regulation of epigenetic mechanisms such as DNA methylation, histone modification, and non-coding RNA-dependent silencing mechanisms, in the face of plant s stress due to low temperatures. Finally, we present a schematic model about the potential responses by plants taking in count their epigenetic memory; considering a global warming scenario and with the presence or absence of extreme specific events of low temperatures.
PMID: 34370110
J Proteomics , IF:4.044 , 2021 Aug : P104349 doi: 10.1016/j.jprot.2021.104349
Proteome analysis reveals a systematic response of cold-acclimated seedlings of an exotic mangrove plant Sonneratia apetala to chilling stress.
Key Laboratory for Subtropical Wetland Ecosystem Research of Ministry of Education, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China.; Key Laboratory for Subtropical Wetland Ecosystem Research of Ministry of Education, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China; Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, College of Environment and Resources, Guangxi Normal University, Guilin, Guangxi 541004, PR China.; Fujian Key Laboratory of Subtropical Plant Physiology and Biochemistry, Fujian Institute of Subtropical Botany, Xiamen, Fujian 361006, PR China.; Key Laboratory for Subtropical Wetland Ecosystem Research of Ministry of Education, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, PR China. Electronic address: zhenghl@xmu.edu.cn.
Low temperature in winter was the most crucial abiotic stress that limits the mangrove afforestation northward. Previous study demonstrated that Sonneratia apetala initially transplanted to high latitude area exhibited a stronger plasticity of cold tolerance. To clarify the underlying mechanism, the physiological and proteomic responses to chilling stress were investigated in S. apetala leaves. Our results found that cold-acclimated seedlings had lower relative electrolyte leakage and MDA content than non-acclimated seedlings. On the contrary, higher chlorophyll content and photosynthetic capacity were observed in cold-acclimated seedlings. With proteomic analyses, the differentially accumulated proteins (DAPs) involved in ROS scavenging, photosynthesis and energy metabolism, carbohydrate metabolism, cofactor biosynthesis, and protein folding were suggested to play important roles in enhancing the cold tolerance of S. apetala. However, the down-regulation DAPs were suggested as a tradeoff between plant growth and chilling response. By the protein-protein interaction analyses, translation elongation factor G, chlorophyll A-B binding protein and ascorbate peroxidase 1 were suggested as the important regulators in cold-acclimated S. apetala seedlings under chilling stress. Based on the above results, a schematic diagram describing the mechanism of cold tolerance of exotic mangrove species S. apetala that was achieved by cold acclimation was presented in this study. SIGNIFICANCE: The major environmental factor limits the mangrove afforestation northward is the low temperature in winter. Previous study reported that Sonneratia apetala grew in high latitude exhibited a higher cold tolerance than that in low latitude, which was suggested as a result of cold acclimation. To further understand "how cold acclimation enhance the cold tolerance in S. apetala", the response of S. apetala subjected to chilling stress with or without cold acclimation was investigated in this study at the physiological and proteomic aspects. Our physiological results showed that S. apetala seedlings treated with cold acclimation exhibited a higher tolerance under chilling stress than that without cold acclimation. By using the comparative proteomic approaches and bioinformatic analyses, various biological processes were suggested to play an important role in enhancing the cold tolerance of S. apetala under chilling stress, such as ROS scavenging, photosynthesis and energy metabolism, carbohydrate metabolism, cofactor biosynthesis, and protein folding. Among these differentially accumulated proteins, translation elongation factor G (eEF-G), chlorophyll A-B binding protein (CAB) and ascorbate peroxidase 1 (APX1) were identified as the hub proteins function in coordinated regulating ROS scavenging, photosynthesis and protein biosynthesis in chloroplast and subsequently enhanced the cold tolerance of S. apetala under chilling stress. Our results provided a further understanding of cold acclimation in improving the cold tolerance in exotic mangrove species S. apetala.
PMID: 34411764
Phytopathology , IF:4.025 , 2021 Aug doi: 10.1094/PHYTO-07-21-0310-R
Xanthomonas oryzae pv. exoribonuclease R is required for complete virulence in rice, optimal motility, and growth under stress.
Centre for Cellular and Molecular Biology CSIR, 28569, Uppal Road, Habsiguda, Hyderabad, Telangana, India, 500007; sarmilaray@gmail.com.; Hyderabad, India.; MRC Institute of Genetics & Molecular Medicine, The University of Edinburgh, Western General Hospital, Edinburgh, UK, Edinburgh, United Kingdom of Great Britain and Northern Ireland; pragya.mittal@igmm.ed.ac.uk.; Center for Plant Molecular Biology, Osmania University, Tarnaka, Hyderabad, Telangana State, India 500007, Hyderabad, India; tayi.lavanya3@gmail.com.; Centre for Cellular and Molecular Biology CSIR, 28569, Hyderabad, Telangana, India; sahitya.bondada@gmail.com.; Centre for Cellular and Molecular Biology CSIR, 28569, Hyderabad, Telangana, India; malayccmb@gmail.com.; Centre for Cellular and Molecular Biology CSIR, 28569, Hyderabad, Telangana, India; hitendrakpatel@gmail.com.; Indian Institute of Science Education and Research Tirupati, 443874, Tirupati, Andhra Pradesh, India; rameshvsonti@gmail.com.
Exoribonuclease R (RNase R) is a 3' hydrolytic exoribonuclease that can degrade structured RNA. Mutation in RNase R affects virulence of certain human pathogenic bacteria. The aim of this study was to determine whether RNase R is required for virulence of the phytopathogen that causes bacterial blight in rice, Xanthomonas oryzae pv. oryzae (Xoo). In silico analysis has indicated that RNase R is highly conserved among various Xanthomonads. Amino acid sequence alignment of Xoo RNase R with RNase R from various taxa indicated that Xoo RNase R clustered with RNase R of order Xanthomonadales. In order to study its role in virulence, a gene disruption mutant of Xoo RNase R (rnr (-)) was generated. The Xoo rnr (-) mutant is moderately virulence deficient and the complementing strain (rnr (-)/pHM1::rnr) rescued the virulence deficiency of the mutant. We investigated swimming and swarming motilities in both nutrient deficient minimal and nutrient optimal media. We observed that rnr (-) mutant has adversely affected the swimming and swarming motilities of Xoo in optimal media. However, in nutrient deficient media only swimming motility was noticeably affected. Growth curves in optimal media at suboptimal temperature (15 degrees C, cold stress) indicate that Xoo rnr (-) mutant grows slower than Xoo wild type (wt) and complementing strain (rnr (-)/pHM1::rnr). Taken together, we report for the first time that RNase R function is necessary for complete virulence of Xoo in rice. It is also important for motility of Xoo in media and for growth of Xoo at suboptimal temperature.
PMID: 34384245
J Zhejiang Univ Sci B , IF:3.066 , 2021 Aug , V22 (8) : P682-694 doi: 10.1631/jzus.B2000697
Hemin-induced increase in saponin content contributes to the alleviation of osmotic and cold stress damage to Conyza blinii in a heme oxygenase 1-dependent manner.
College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.; Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China.; College of Life Science, Nanjing Agricultural University, Nanjing 210095, China.; College of Life Science, Sichuan Agricultural University, Ya'an 625014, China. chenhui@sicau.edu.cn.
Hemin can improve the stress resistance of plants through the heme oxygenase system. Additionally, substances contained in plants, such as secondary metabolites, can improve stress resistance. However, few studies have explored the effects of hemin on secondary metabolite content. Therefore, the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study. Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C. blinii under osmotic stress and cold stress. Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C. blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway, thus increasing the saponin content. Moreover, the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX (ZnPPIX). This study revealed that hemin can increase the saponin content of C. blinii and alleviate the damage caused by abiotic stress, and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.
PMID: 34414702
FEBS Open Bio , IF:2.693 , 2021 Aug doi: 10.1002/2211-5463.13275
Identification of reliable reference genes for quantitative real-time PCR analysis of the Rhus chinensis Mill. leaf response to temperature changes.
College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Province, Changsha, 410128, China.; Hunan Engineering Laboratory for Good Agricultural Practice and Comprehensive Utilization of Famous-Region Medicinal Plants, Changsha, 410128, China.; Hunan Academy of Forestry, Hunan Province, Changsha, 410004, China.; Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong Special Administrative Region, PR China.; School of Metallurgy and Environment, Central South University, Changsha, P.R. China.
Rhus chinensis Mill. (RCM) is the host plant of Galla chinensis, which is valued in traditional medicine. Environmental temperature directly determines the probability of gallnut formation and RCM growth. At present, there is no experiment to systematically analyse the stability of internal reference gene (RG) expression in RCM. In this experiment, leaves that did not form gallnuts were used as the control group, while leaves that formed gallnuts were used as the experimental group. First, we conducted transcriptome experiments on RCM leaves to obtain 45,103 differential genes and functional enrichment annotations between the two groups. On this basis, this experiment established a transcriptional gene change model of leaves in the process of gallnut formation after being bitten by aphids, and RCM reference candidate genes were screened from RNA sequencing (RNA-seq) data. This study is based on RCM transcriptome data and evaluates the stability of 11 potential reference genes under cold stress (4 degrees C) and heat stress (34 degrees C), using three statistical algorithms (geNorm, NormFinder, and BestKeeper). The results show that GAPDH1 + PP2A2/UBQ are stable reference genes under heat stress, while GAPDH1 + ACT are the most stable under cold stress. This study is the first to screen candidate reference genes in RCM and could help guide future molecular studies in this genus.
PMID: 34403204
Genes Genomics , IF:1.839 , 2021 Aug doi: 10.1007/s13258-021-01143-7
Overexpression of antisense phosphatase 2C affords cold resistance in hybrid Populus davidiana x Populus bolleana.
Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Northest Forestry University, No. 26 Hexing Road Xiangfang District, Harbin, 150040, P.R. China.; Environmental Biotechnology Laboratory, Department of Biotechnology, University of Azad Jammu and Kashmir, Chehla Campus, Muzaffarabad, 13100, Azad Kashmir, Pakistan.; Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Northest Forestry University, No. 26 Hexing Road Xiangfang District, Harbin, 150040, P.R. China. guanqingjie@nefu.edu.cn.
BACKGROUND: Overexpression of the abiotic and biotic stress-resistance genes of the plant signaling pathway is well known for its significant role in the regulation of plant growth and enhancement of the productivity of agricultural land under changing climatic conditions. OBJECTIVES: This research aimed to clone Populus davidiana x Populus bolleana PP2C (PdPP2C) gene and analyze its structure and function, and downregulate PdPP2C by overexpression of its antisense PdPP2C (AS-PdPP2C) gene for enhancing cold resistance in transgenic lines of hybrid P. davidiana x P. bolleana. METHODS: PdPP2C was cloned and transformed to identify its function, and its antisense was overexpressed via downregulation to increase the cold resistance in transgenic lines of hybrid P. davidiana x P. bolleana. RESULTS: Antisense inhibition of protein phosphatase 2C accelerates the cold acclimation of Poplar (P. davidiana x P. bolleana) gene in terms of antifreeze. CONCLUSION: PdPP2C was expressed in the roots, stems, and leaves of P. davidiana x P. bolleana, and the expression was higher in the leaves. The expression of PdPP2C was also significantly downregulated at low-temperature (0 degrees C and 4 degrees C) stress. The relative conductivity and malondialdehyde content of non-transgenic lines were higher than those of AS-PdPP2C lines after 2 days of cold treatment at - 1 degrees C. The leaves of the transgenic lines were not wilted and showed no chlorosis compared with those of the non-transgenic lines. The AS-PdPP2C transgenic lines also showed higher freezing resistance than the non-transgenic lines. AS-PdPP2C participated in the regulation of freezing resistance.
PMID: 34338987