Plant Physiol , IF:6.902 , 2020 Jul doi: 10.1104/pp.20.00594
The class-III gibberellin 2-oxidases AtGA2ox9 and AtGA2ox10 contribute to cold stress tolerance and fertility.
TU Braunschweig CITY: Braunschweig POSTAL_CODE: 38106 Germany [DE].; TU Braunschweig CITY: Braunschweig Germany [DE].; Technische Universitat Braunschweig CITY: Braunschweig POSTAL_CODE: D-38106 Germany [DE] m.pimenta@tu-bs.de.
Many developmental processes in plants are regulated by gibberellin hormones. Gibberellin homeostasis is achieved via complex biosynthetic and catabolic pathways. Gibberellin catabolic enzymes include GA 2-oxidases that are classified into three classes. Members of class-III GA 2-oxidases typically act on GA precursors containing a C20-skeleton. Here, we identified two further members of this class of GA 2-oxidases, namely AtGA2ox9 and AtGA2ox10, in the Arabidopsis (Arabidopsis thaliana) genome. Both genes encode enzymes that have functional similarities to AtGA2ox7 and AtGA2ox8, which are class-III GA 2-oxidases that 2ss-hydroxylate C20-GAs. Previously unknown for GA 2-oxidases, AtGA2ox9 performs 2alpha-hydroxylation of C19-GAs and harbors putative desaturate activity of C20-GAs. Additionally, AtGA2ox9 and AtGA2ox10 exhibit GA 20-oxidase activity. AtGA2ox9 oxidizes carbon-20 to form tricarboxylic acid C20-GAs, whereas AtGA2ox10 produces C19-GA9. AtGA2ox9 transcript levels increase after cold treatment and AtGA2ox10 is expressed mainly in the siliques of Arabidopsis plants. Atga2ox9 loss-of-function mutants are more sensitive to freezing temperatures, whereas Atga2ox10 loss-of-function mutants produce considerably more seeds per silique than wild-type plants. We conclude that, in Arabidopsis, AtGA2ox9 and AtGA2ox10 contribute to freezing tolerance and regulate seed production, respectively.
PMID: 32661062
J Exp Bot , IF:5.908 , 2020 Jul doi: 10.1093/jxb/eraa325
Deletion of maize RDM4 suggests a role in endosperm maturation as well as vegetative and stress-responsive growth.
College of Grassland Science and Technology, China Agricultural University, Beijing, China.; Key Laboratory of Pratacultural Science, Beijing Municipality, Haidian District, Beijing, China.; Department of Agronomy and Horticulture, Center for Plant Science Innovation, Beadle Center for Biotechnology, University of Nebraska, Lincoln, USA.; Bond Life Sciences Center, Division of Biological Sciences, Interdisciplinary Plant Group, University of Missouri, Columbia, USA.; Proteomics and Metabolomics Core facility, University of Nebraska-Lincoln, Lincoln, USA.; School of Biological Sciences, Center for Plant Science Innovation, Beadle Center for Biotechnology, University of Nebraska, Lincoln, USA.
Opaque kernels in maize may result from mutations in many genes, such as OPAQUE-2. In this study, a maize null mutant of RNA-DIRECTED DNA METHYLATION 4 (RDM4) shows an opaque kernel phenotype, as well as plant developmental delay, male sterility, and altered response to cold stress. We found that in opaque kernels, all zein proteins were reduced and amino acid content was changed, including increased lysine. Transcriptomic and proteomic analysis confirmed the zein reduction and proteomic rebalancing of non-zein proteins, which was quantitatively and qualitatively different from opaque-2. Global transcriptional changes were found in endosperm and leaf, including many transcription factors, and tissue specific expressed genes. Furthermore, of the more than 8000 significantly differentially expressed genes in wild type in response to cold, a significant proportion (25.9% in moderate cold stress and 40.8% in near freezing stress) were not differentially expressed in response to cold in rdm4, suggesting RDM4 may participate in regulation of abiotic stress tolerance. This initial characterization of maize RDM4 provides a basis for further investigating its function in endosperm and leaf, and as a regulator of normal and stress responsive development.
PMID: 32667993
iScience , IF:4.447 , 2020 Jul , V23 (7) : P101331 doi: 10.1016/j.isci.2020.101331
Translational Components Contribute to Acclimation Responses to High Light, Heat, and Cold in Arabidopsis.
Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany.; Computational Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany.; Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Grosshadernerstrasse 2-4, 82152 Planegg-Martinsried, Germany. Electronic address: leister@lmu.de.
Plant metabolism is broadly reprogrammed during acclimation to abiotic changes. Most previous studies have focused on transitions from standard to single stressful conditions. Here, we systematically analyze acclimation processes to levels of light, heat, and cold stress that subtly alter physiological parameters and assess their reversibility during de-acclimation. Metabolome and transcriptome changes were monitored at 11 different time points. Unlike transcriptome changes, most alterations in metabolite levels did not readily return to baseline values, except in the case of cold acclimation. Similar regulatory networks operate during (de-)acclimation to high light and cold, whereas heat and high-light responses exhibit similar dynamics, as determined by surprisal and conditional network analyses. In all acclimation models tested here, super-hubs in conditional transcriptome networks are enriched for components involved in translation, particularly ribosomes. Hence, we suggest that the ribosome serves as a common central hub for the control of three different (de-)acclimation responses.
PMID: 32679545
Cells , IF:4.366 , 2020 Jul , V9 (8) doi: 10.3390/cells9081749
Polyamines and Their Biosynthesis/Catabolism Genes Are Differentially Modulated in Response to Heat Versus Cold Stress in Tomato Leaves (Solanum lycopersicum L.).
Sustainable Agricultural Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.; Center of Plant Biology, Department of Horticulture and Landscape Architecture, Purdue University, W. Lafayette, IN 47907, USA.
Polyamines (PAs) regulate growth in plants and modulate the whole plant life cycle. They have been associated with different abiotic and biotic stresses, but little is known about the molecular regulation involved. We quantified gene expression of PA anabolic and catabolic pathway enzymes in tomato (Solanum lycopersicum cv. Ailsa Craig) leaves under heat versus cold stress. These include arginase 1 and 2, arginine decarboxylase 1 and 2, agmatine iminohydrolase/deiminase 1, N-carbamoyl putrescine amidase, two ornithine decarboxylases, three S-adenosylmethionine decarboxylases, two spermidine synthases; spermine synthase; flavin-dependent polyamine oxidases (SlPAO4-like and SlPAO2) and copper dependent amine oxidases (SlCuAO and SlCuAO-like). The spatiotemporal transcript abundances using qRT-PCR revealed presence of their transcripts in all tissues examined, with higher transcript levels observed for SAMDC1, SAMDC2 and ADC2 in most tissues. Cellular levels of free and conjugated forms of putrescine and spermidine were found to decline during heat stress while they increased in response to cold stress, revealing their differential responses. Transcript levels of ARG2, SPDS2, and PAO4-like increased in response to both heat and cold stresses. However, transcript levels of ARG1/2, AIH1, CPA, SPDS1 and CuAO4 increased in response to heat while those of ARG2, ADC1,2, ODC1, SAMDC1,2,3, PAO2 and CuPAO4-like increased in response to cold stress, respectively. Transcripts of ADC1,2, ODC1,2, and SPMS declined in response to heat stress while ODC2 transcripts declined under cold stress. These results show differential expression of PA metabolism genes under heat and cold stresses with more impairment clearly seen under heat stress. We interpret these results to indicate a more pronounced role of PAs in cold stress acclimation compared to that under heat stress in tomato leaves.
PMID: 32707844
Plant Cell Physiol , IF:4.062 , 2020 Jul doi: 10.1093/pcp/pcaa091
CsSWEET1a and CsSWEET17 Mediate Growth and Freezing Tolerance by Promoting Sugar Transport across the Plasma Membrane.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, China.
Sugars will eventually be exported transporters (SWEETs) are important in plant biological processes. Expression levels of CsSWEET1a and CsSWEET17 are induced by cold acclimation (CA) and cold stress in Camellia sinensis. Here, we found that CsSWEET17 was alternatively spliced, and its exclusion (Ex) transcript was associated with CA process. Both plasma membrane-localized CsSWEET1a and CsSWEET17 transport hexoses, but cytoplasm-localized CsSWEET17-Ex does not. These results indicate that alternative splicing may be involved in regulating the function of SWEET transporter in response to the low temperature in plants. The extra C-terminal of the CsSWEET17, which was not found in the tonoplast fructose transporter AtSWEET17, did not affect its plasma membrane localization but promoted its sugar transport activities. The overexpression (OE) of CsSWEET1a and CsSWEET17 genes resulted in an increased sugar uptake in Arabidopsis, affecting plant germination and growth. The leaf and seed sizes of the CsSWEET17-OE lines were significantly larger than those of the wild-type. Moreover, the OE of CsSWEET1a and CsSWEET17 significantly reduced the relative electrolyte leakage levels under freezing stress. Compared with the wild-type, the expression of AtCWINV genes was suppressed in both CsSWEET1a-OE and CsSWEET17-OE lines, indicating the alteration of sugar contents in the cell walls of the OE lines. Furthermore, the interaction between CsSWEET1a and CsSWEET17 was confirmed using yeast two-hybrid and bimolecular fluorescence complementation assays. We showed that CsSWEET1a and CsSWEET17 form homo/heterodimers in the plasma membrane and mediate the partitioning of sugars between the cytoplasm and the apoplast, thereby regulating plant growth and freezing tolerance.
PMID: 32645157
Sci Rep , IF:3.998 , 2020 Jul , V10 (1) : P12240 doi: 10.1038/s41598-020-69253-y
Effects of nitric oxide on the GABA, polyamines, and proline in tea (Camellia sinensis) roots under cold stress.
College of Horticulture, Nanjing Agricultural University, No.1 Weigang, Nanjing, 210095, Jiangsu, China.; Institute of Tea Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, 417100, China.; College of Horticulture, Nanjing Agricultural University, No.1 Weigang, Nanjing, 210095, Jiangsu, China. zhuxujun@njau.edu.cn.
Tea plant often suffers from low temperature induced damage during its growth. How to improve the cold resistance of tea plant is an urgent problem to be solved. Nitric oxide (NO), gamma-aminobutyric acid (GABA) and proline have been proved that can improve the cold resistance of tea plants, and signal transfer and biosynthesis link between them may enhance their function. NO is an important gas signal material in plant growth, but our understanding of the effects of NO on the GABA shunt, proline and NO biosynthesis are limited. In this study, the tea roots were treated with a NO donor (SNAP), NO scavenger (PTIO), and NO synthase inhibitor (L-NNA). SNAP could improve activities of arginine decarboxylase, ornithine decarboxylase, glutamate decarboxylase, GABA transaminase and Delta1-pyrroline-5-carboxylate synthetase and the expression level of related genes during the treatments. The contents of putrescine and spermidine under SNAP treatment were 45.3% and 37.3% higher compared to control at 24 h, and the spermine content under PTIO treatment were 57.6% lower compare to control at 12 h. Accumulation of proline of SNAP and L-NNA treatments was 52.2% and 43.2% higher than control at 48 h, indicating other pathway of NO biosynthesis in tea roots. In addition, the NO accelerated the consumption of GABA during cold storage. These facts indicate that NO enhanced the cold tolerance of tea, which might regulate the metabolism of the GABA shunt and of proline, associated with NO biosynthesis.
PMID: 32699288
BMC Genomics , IF:3.594 , 2020 Jul , V21 (1) : P521 doi: 10.1186/s12864-020-06929-9
The alcohol dehydrogenase gene family in sugarcane and its involvement in cold stress regulation.
Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.; Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.; Department of Genetics, Hazara University, Mansehra, Pakistan.; Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China. queyouxiong@126.com.; Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China. queyouxiong@126.com.
BACKGROUND: Alcohol dehydrogenases (ADHs) in plants are encoded by a multigene family. ADHs participate in growth, development, and adaptation in many plant species, but the evolution and function of the ADH gene family in sugarcane is still unclear. RESULTS: In the present study, 151 ADH genes from 17 species including 32 ADH genes in Saccharum spontaneum and 6 ADH genes in modern sugarcane cultivar R570 were identified. Phylogenetic analysis demonstrated two groups of ADH genes and suggested that these genes underwent duplication during angiosperm evolution. Whole-genome duplication (WGD)/segmental and dispersed duplications played critical roles in the expansion of ADH family in S. spontaneum and R570, respectively. ScADH3 was cloned and preferentially expressed in response to cold stress. ScADH3 conferred improved cold tolerance in E. coli cells. Ectopic expression showed that ScADH3 can also enhance cold tolerance in transgenic tobacco. The accumulation of reactive oxygen species (ROS) in leaves of transgenic tobacco was significantly lower than in wild-type tobacco. The transcript levels of ROS-related genes in transgenic tobacco increased significantly. ScADH3 seems to affect cold tolerance by regulating the ROS-related genes to maintain the ROS homeostasis. CONCLUSIONS: This study depicted the size and composition of the ADH gene family in 17 species, and investigated their evolution pattern. Comparative genomics analysis among the ADH gene families of S. bicolor, R570 and S. spontaneum revealed their close evolutionary relationship. Functional analysis suggested that ScADH3, which maintained the steady state of ROS by regulating ROS-related genes, was related to cold tolerance. These findings will facilitate research on evolutionary and functional aspects of the ADH genes in sugarcane, especially for the understanding of ScADH3 under cold stress.
PMID: 32727370
BMC Genomics , IF:3.594 , 2020 Jul , V21 (1) : P507 doi: 10.1186/s12864-020-06917-z
Enhanced sugar accumulation and regulated plant hormone signalling genes contribute to cold tolerance in hypoploid Saccharum spontaneum.
Sugarcane Research Institute, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, PR China.; Chuxiong normal university, Chuxiong, 675000, Yunnan Province, PR China.; Wenshan Academy of Agricultural Sciences, Wenshan, 663000, Yunnan Province, PR China.; Sugarcane Research Institute, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, PR China. yangqinghui@163.com.; Sugarcane Research Institute, Yunnan Agricultural University, Kunming, 650201, Yunnan Province, PR China. x.h_wang@163.com.
BACKGROUND: Wild sugarcane Saccharum spontaneum plants vary in ploidy, which complicates the utilization of its germplasm in sugarcane breeding. Investigations on cold tolerance in relation to different ploidies in S. spontaneum may promote the exploitation of its germplasm and accelerate the improvement of sugarcane varieties. RESULTS: A hypoploid clone 12-23 (2n = 54) and hyperploid clone 15-28 (2n = 92) of S. spontaneum were analysed under cold stress from morphological, physiological, and transcriptomic perspectives. Compared with clone 15-28, clone 12-23 plants had lower plant height, leaf length, internode length, stem diameter, and leaf width; depressed stomata and prominent bristles and papillae; and thick leaves with higher bulliform cell groups and thicker adaxial epidermis. Compared with clone 15-28, clone 12-23 showed significantly lower electrical conductivity, significantly higher water content, soluble protein content, and superoxide dismutase activity, and significantly higher soluble sugar content and peroxidase activity. Under cold stress, the number of upregulated genes and downregulated genes of clone 12-23 was higher than clone 15-28, and many stress response genes and pathways were affected and enriched to varying degrees, particularly sugar and starch metabolic pathways and plant hormone signalling pathways. Under cold stress, the activity of 6-phosphate glucose trehalose synthase, trehalose phosphate phosphatase, and brassinosteroid-signalling kinase and the content of trehalose and brassinosteroids of clone 12-23 increased. CONCLUSIONS: Compared with hyperploid clone 15-28, hypoploid clone 12-23 maintained a more robust osmotic adjustment system through sugar accumulation and hormonal regulation, which resulted in stronger cold tolerance.
PMID: 32698760
BMC Plant Biol , IF:3.497 , 2020 Jul , V20 (1) : P332 doi: 10.1186/s12870-020-02534-w
TRANSTHYRETIN-LIKE and BYPASS1-LIKE co-regulate growth and cold tolerance in Arabidopsis.
The Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China.; The Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China. zhanghua@lzu.edu.cn.; The Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, People's Republic of China. lizhean@lzu.edu.cn.; School of Forestry, Beijing Forestry University, Beijing, 100083, People's Republic of China. lizhean@lzu.edu.cn.
BACKGROUND: Cold stress inhibits normal physiological metabolism in plants, thereby seriously affecting plant development. Meanwhile, plants also actively adjust their metabolism and development to adapt to changing environments. Several cold tolerance regulators have been found to participate in the regulation of plant development. Previously, we reported that BYPASS1-LIKE (B1L), a DUF793 family protein, participates in the regulation of cold tolerance, at least partly through stabilizing C-REPEAT BINDING FACTORS (CBFs). In this study, we found that B1L interacts with TRANSTHYRETIN-LIKE (TTL) protein, which is involved in brassinosteroid (BR)-mediated plant growth and catalyses the synthesis of S-allantoin, and both proteins participate in modulating plant growth and cold tolerance. RESULTS: The results obtained with yeast two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays showed that B1L directly interacted with TTL. Similar to the ttl-1 and ttl-2 mutants, the b1l mutant displayed a longer hypocotyl and greater fresh weight than wild type, whereas B1L-overexpressing lines exhibited a shorter hypocotyl and reduced fresh weight. Moreover, ttl-1 displayed freezing tolerance to cold treatment compared with WT, whereas the b1l mutant and TTL-overexpressing lines were freezing-sensitive. The b1l ttl double mutant had a developmental phenotype and freezing tolerance that were highly similar to those of ttl-1 compared to b1l, indicating that TTL is important for B1L function. Although low concentrations of brassinolide (0.1 or 1 nM) displayed similarly promoted hypocotyl elongation of WT and b1l under normal temperature, it showed less effect to the hypocotyl elongation of b1l than to that of WT under cold conditions. In addition, the b1l mutant also contained less amount of allantoin than Col-0. CONCLUSION: Our results indicate that B1L and TTL co-regulate development and cold tolerance in Arabidopsis, and BR and allantoin may participate in these processes through B1L and TTL.
PMID: 32664862
Planta , IF:3.39 , 2020 Jul , V252 (2) : P26 doi: 10.1007/s00425-020-03431-0
Molecular dissection of two homoeologous wheat genes encoding RING H2-type E3 ligases: TaSIRFP-3A and TaSIRFP-3B.
Plant Genomics Lab, Department of Bio-Resources Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea.; Plant Genomics Lab, Department of Bio-Resources Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea. csjang@kangwon.ac.kr.
MAIN CONCLUSION: Two homoeologous wheat genes, TaSIRFP-3A and TaSIRFP-3B, encode the RING-HC-type E3 ligases that play an inhibitory role in sucrose metabolism in response to cold stress. In higher plants, the attachment of ubiquitin (Ub) and the subsequent recognition and degradation by the 26S proteasome affects a variety of cellular functions that are essential for survival. Here, we characterized the two homoeologous wheat genes encoding the really interesting new gene (RING) HC-type E3 ligases: TaSIRFP-3A and TaSIRFP-3B (Triticum aestivum SINA domain including RING finger protein 1 and 2), which regulate target proteins via the Ub/26S proteasome system. The TaSIRFP-3A gene was highly expressed under cold stress. In contrast, its homoeologous gene, TaSIRFP-3B, showed only a slight increase in expression levels in shoots. Despite these differences, both the proteins exhibited E3 ligase activity with the cytosol- and nucleus-targeted localization, demonstrating their conserved molecular function. Heterogeneous overexpression of TaSIRFP-3A or TaSIRFP-3B in Arabidopsis showed delayed plant growth causing a reduction in sucrose synthase enzymatic activity and photosynthetic sucrose synthesis, by regulating sucrose synthase proteins. TaSIRFP-3A- or TaSIRFP-3B-overexpressing plants showed higher hypersensitivity under cold stress than WT plants with an accumulation of reactive oxygen species (ROS). These results suggest that the negative regulation of TaSIRFP-3A and TaSIRFP-3B in response to cold stress is involved in sucrose metabolism.
PMID: 32696139
Planta , IF:3.39 , 2020 Jul , V252 (2) : P23 doi: 10.1007/s00425-020-03421-2
Sucrose phosphate synthase (SPS), sucrose synthase (SUS) and their products in the leaves of Miscanthus x giganteus and Zea mays at low temperature.
Department of Plant Biochemistry and Physiology, Plant Breeding and Acclimatization Institute, National Research Institute, Radzikow, 05-870, Blonie, Poland. a.bilska@ihar.edu.pl.; Department of Plant Physiology and Ecology, Institute of Biology and Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland. a.bilska@ihar.edu.pl.; Department of Animal Physiology and Reproduction, Institute of Biology and Biotechnology, University of Rzeszow, Werynia 2, 36-100, Kolbuszowa, Poland.; Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, 02-093, Warsaw, Poland.; Department of Plant Physiology and Ecology, Institute of Biology and Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland.; Department of Plant Pathology, Plant Breeding and Acclimatization Institute, National Research Institute, Radzikow, 05-870, Blonie, Poland.
MAIN CONCLUSION: The changes in the expression of key sugar metabolism enzymes (SPS and SUS), sucrose content and arrangement of chloroplast starch may play a significant role in the cold response in M. giganteus and maize plants. To understand the mechanism of the chilling-response of two closely-related C4 plants, we investigated the changes in the expression of sucrose phosphate synthase (SPS) and sucrose synthase (SUS) as well as changes in their potential products: sucrose, cellulose and starch in the leaves of Miscanthus x giganteus and Zea mays. Low temperature (12-14 degrees C) increased SPS content in Miscanthus (MG) and chilling-sensitive maize line (Zm-S), but not in chilling-tolerant one (Zm-T). In Zm-S line, chilling also caused the higher intensity of labelling of SPS in the cytoplasm of mesophyll cells, as demonstrated by electron microscopy. SUS labelling was also increased by cold stress only in MG plants what was observed in the secondary wall between mesophyll and bundle sheath cells, as well as in the vacuoles of companion cells. Cold led to a marked increase in total starch grain area in the chloroplasts of Zm-S line. In turn, Fourier transform infrared spectroscopy (FTIR) showed a slight shift in the cellulose band position, which may indicate the formation of more compact cellulose arrangement in Zm-T maize line. In conclusion, this work presents new findings supporting diversified cold-response, not only between two C4 plant species but also within one species of maize.
PMID: 32676847
Planta , IF:3.39 , 2020 Jul , V252 (2) : P19 doi: 10.1007/s00425-020-03423-0
Effects of low temperature on photoinhibition and singlet oxygen production in four natural accessions of Arabidopsis.
Department of Biochemistry, Molecular Plant Biology, University of Turku, 20014, Turku, Finland.; Global Change Research Institute of the Czech Academy of Sciences, Belidla 986, 4a, Brno, 603 00, Czech Republic.; Department of Biochemistry, Molecular Plant Biology, University of Turku, 20014, Turku, Finland. esatyy@utu.fi.
MAIN CONCLUSIONS: Low temperature decreases PSII damage in vivo, confirming earlier in vitro results. Susceptibility to photoinhibition differs among Arabidopsis accessions and moderately decreases after 2-week cold-treatment. Flavonols may alleviate photoinhibition. The rate of light-induced inactivation of photosystem II (PSII) at 22 and 4 degrees C was measured from natural accessions of Arabidopsis thaliana (Rschew, Tenela, Columbia-0, Coimbra) grown under optimal conditions (21 degrees C), and at 4 degrees C from plants shifted to 4 degrees C for 2 weeks. Measurements were done in the absence and presence of lincomycin (to block repair). PSII activity was assayed with the chlorophyll a fluorescence parameter Fv/Fm and with light-saturated rate of oxygen evolution using a quinone acceptor. When grown at 21 degrees C, Rschew was the most tolerant to photoinhibition and Coimbra the least. Damage to PSII, judged from fitting the decrease in oxygen evolution or Fv/Fm to a first-order equation, proceeded more slowly or equally at 4 than at 22 degrees C. The 2-week cold-treatment decreased photoinhibition at 4 degrees C consistently in Columbia-0 and Coimbra, whereas in Rschew and Tenela the results depended on the method used to assay photoinhibition. The rate of singlet oxygen production by isolated thylakoid membranes, measured with histidine, stayed the same or slightly decreased with decreasing temperature. On the other hand, measurements of singlet oxygen from leaves with Singlet Oxygen Sensor Green suggest that in vivo more singlet oxygen is produced at 4 degrees C. Under high light, the PSII electron acceptor QA was more reduced at 4 than at 22 degrees C. Singlet oxygen production, in vitro or in vivo, did not decrease due to the cold-treatment. Epidermal flavonols increased during the cold-treatment and, in Columbia-0 and Coimbra, the amount correlated with photoinhibition tolerance.
PMID: 32671474
J Plant Physiol , IF:3.013 , 2020 Aug , V251 : P153225 doi: 10.1016/j.jplph.2020.153225
Hormonal interplay in the regulation of fruit ripening and cold acclimation in avocados.
Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain; Research Institute of Nutrition and Food Safety, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain.; Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain; Research Institute of Nutrition and Food Safety, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028, Barcelona, Spain. Electronic address: smunne@ub.edu.
Avocados (Persea americana Mill.) are climacteric fruits, the ripening of which during postharvest at room temperature is strongly ethylene dependent. However, the role of other phytohormones in the modulation of postharvest ripening of avocados is still poorly understood. The optimal ripening state of avocados is attained a few days after harvest depending on the genotype, growing region and initial maturity stage of the fruit, and cold temperature storage is commonly used to delay this process. Here, we hypothesized that the ripening of avocados at room temperature may be governed not only by ethylene, but also by other phytohormones. With this aim, we analyzed the hormonal profiling of avocados subjected to either 4 degrees C and 25 degrees C during 10 days of postharvest. A biphasic response was observed during postharvest ripening of avocados at room temperature. While ethylene alone appeared to govern fruit ripening during the first transfer from cold to room temperature, a complex hormonal interplay occurred during ripening of avocados leading to a progressive fruit softening at room temperatures. Aside from ethylene, auxin, gibberellins, jasmonates and ABA appeared to be involved in avocado fruit ripening during postharvest at room temperature. Cold storage for a period of 10 days inhibited this hormonal response related to ripening. Furthermore, avocados stored at cold temperatures underwent a quick response in order to tolerate cold stress leading to changes in endogenous ABA and jasmonates. We conclude that a complex hormonal interplay, rather than ethylene alone, modulates postharvest ripening of avocados and that cold storage can effectively be employed as a technique to prevent avocados from a rapid ripening thanks to the cold stress tolerance mechanisms deployed by fruits through multiple hormonal regulation.
PMID: 32653729
Biochem Biophys Res Commun , IF:2.985 , 2020 Jul , V527 (4) : P929-934 doi: 10.1016/j.bbrc.2020.05.046
The N-terminal and third transmembrane domain of PsCor413im1 are essential for targeting to chloroplast envelope membrane.
College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China.; Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, 150040, China; College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin, 150030, China. Electronic address: aiminzhou@neau.edu.cn.
Cold-regulated (COR) genes, located downstream of the C-repeat binding factors (CBFs) in cold signaling pathways, play a central role in plant response to cold stress. In our previous studies, a Cor413 chloroplast envelope membrane protein, PsCor413im1, was identified from the cold-tolerant plant Phlox subulata. Its overexpression enhanced cold tolerance and altered AtCor15 expression in Arabidopsis. In the present study, the function of PsCor413im1 was further investigated. Transmission electron microscope observation showed that the chloroplast envelope membrane of cold-treated transgenic Arabidopsis seedlings was more stable than that of cold-treated wild-type seedlings. Subcellular localization of green fluorescent protein as a marker revealed that the N-terminal and putative third transmembrane domain (TMD) of PsCor413im1 were essential for its targeting of the chloroplast envelope membrane. Furthermore, overexpression of PsCor413im1 fragments containing N-terminal and third TMD also altered the expression of AtCor15 genes in Arabidopsis. Overall, our results suggest that PsCor413im1 may stabilize the chloroplast envelope membrane under cold stress, and its N-terminal and third TMD are important for its targeting capability and function.
PMID: 32423814
Plants (Basel) , IF:2.762 , 2020 Jul , V9 (7) doi: 10.3390/plants9070890
Identification and Expression Analysis of Cold Shock Protein 3 (BcCSP3) in Non-Heading Chinese Cabbage (Brassica rapa ssp. chinensis).
State Key Laboratory of Crop Genetics and Germplasm Enhancement/Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture/Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China.; College of Life Sciences and Food Engineering, Huaiyin Institute of Technology, Huai an 223003, China.
A cold-related protein, cold shock protein 3 (BcCSP3), was isolated from non-heading Chinese cabbage in this study. BcCSP3 can encode 205 amino acids (aa) with an open reading frame (ORF) of 618 base pairs (bp). Multiple sequence alignment and phylogenetic tree analyses showed that BcCSP3 contains an N-terminal cold shock domain and is highly similar to AtCSP2, their kinship is recent. Real-time quantitative polymerase chain reaction (RT-qPCR) showed that the expression level of BcCSP3 in stems and leaves is higher than that in roots. Compared with other stress treatments, the change in BcCSP3 expression level was most pronounced under cold stress. In addition, a BcCSP3-GFP fusion protein was localized to the nucleus and cytoplasm. These results indicated that BcCSP3 may play an important role in response to cold stress in non-heading Chinese cabbage. This work may provide a reference for the identification and expression analysis of other CSP genes in non-heading Chinese cabbage.
PMID: 32674472
PLoS One , IF:2.74 , 2020 , V15 (7) : Pe0236588 doi: 10.1371/journal.pone.0236588
Integrated transcriptomic and metabolomic analyses of yellow horn (Xanthoceras sorbifolia) in response to cold stress.
College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China.; Shanxi Key Laboratory of Functional Oil Tree Cultivation and Research, Taigu, Shanxi, China.
Xanthoceras sorbifolia, a medicinal and oil-rich woody plant, has great potential for biodiesel production. However, little study explores the link between gene expression level and metabolite accumulation of X. sorbifolia in response to cold stress. Herein, we performed both transcriptomic and metabolomic analyses of X. sorbifolia seedlings to investigate the regulatory mechanism of resistance to low temperature (4 degrees C) based on physiological profile analyses. Cold stress resulted in a significant increase in the malondialdehyde content, electrolyte leakage and activity of antioxidant enzymes. A total of 1,527 common differentially expressed genes (DEGs) were identified, of which 895 were upregulated and 632 were downregulated. Annotation of DEGs revealed that amino acid metabolism, glycolysis/gluconeogenesis, starch and sucrose metabolism, galactose metabolism, fructose and mannose metabolism, and the citrate cycle (TCA) were strongly affected by cold stress. In addition, DEGs within the plant mitogen-activated protein kinase (MAPK) signaling pathway and TF families of ERF, WRKY, NAC, MYB, and bHLH were transcriptionally activated. Through metabolomic analysis, we found 51 significantly changed metabolites, particularly with the analysis of primary metabolites, such as sugars, amino acids, and organic acids. Moreover, there is an overlap between transcript and metabolite profiles. Association analysis between key genes and altered metabolites indicated that amino acid metabolism and sugar metabolism were enhanced. A large number of specific cold-responsive genes and metabolites highlight a comprehensive regulatory mechanism, which will contribute to a deeper understanding of the highly complex regulatory program under cold stress in X. sorbifolia.
PMID: 32706804
PLoS One , IF:2.74 , 2020 , V15 (7) : Pe0236349 doi: 10.1371/journal.pone.0236349
Genome-wide analysis and transcript profiling of PSKR gene family members in Oryza sativa.
Plant Molecular Biology Laboratory, Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, India.; School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, JK, India.
Peptide signalling is an integral part of cell-to-cell communication which helps to relay the information responsible for coordinating cell proliferation and differentiation. Phytosulfokine Receptor (PSKR) is a transmembrane LRR-RLK family protein with a binding site for small signalling peptide, phytosulfokine (PSK). PSK signalling through PSKR promotes normal growth and development and also plays a role in defense responses. Like other RLKs, these PSKRs might have a role in signal transduction pathways related to abiotic stress responses. Genome-wide analysis of phytosulfokine receptor gene family has led to the identification of fifteen putative members in the Oryza sativa genome. The expression analysis of OsPSKR genes done using RNA-seq data, showed that these genes were differentially expressed in different tissues and responded specifically to heat, salt, drought and cold stress. Furthermore, the real-time quantitative PCR for fifteen OsPSKR genes revealed temporally and spatially regulated gene expression corresponding to salinity and drought stress. Our results provide useful information for a better understanding of OsPSKR genes and provide the foundation for additional functional exploration of the rice PSKR gene family in development and stress response.
PMID: 32701993
Plant Signal Behav , IF:1.671 , 2020 Jul : P1785668 doi: 10.1080/15592324.2020.1785668
The role of NAC transcription factor in plant cold response.
State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University , Tai'an, Shandong, China.
The NAC transcription factor (TF) is one of the largest families of TFs in plants and plays an important role in plant growth, development, and response to environmental stress. The structural and functional characteristics of NAC TFs have been uncovered in the past years, including sequence binding features of the DNA-binding domain located in the N-terminus and dynamic interplay between the domain located at the C-terminus and other proteins. Studies on NAC TF are increasing in number; these studies distinctly contribute to our understanding of the regulatory networks of NAC-mediated complex signaling and transcriptional reprogramming. Previous studies have indicated that NAC TFs are key regulators of the plant stress response. However, these studies have been for six years so far and mainly focused on drought and salt stress. There are relatively few reports about NAC TFs in plant cold signal pathway and no related reviews have been published. In this review article, we summarize the structural features of NAC TFs, the target genes, upstream regulators and interaction proteins of stress-responsive NAC TFs, and the roles NAC TFs play in plant cold stress signal pathway.
PMID: 32662739
Plant Signal Behav , IF:1.671 , 2020 Jul : P1780403 doi: 10.1080/15592324.2020.1780403
ABA enhanced cold tolerance of wheat 'dn1' via increasing ROS scavenging system.
College of Life Science, Northeast Agricultural University , Harbin, Heilongjiang, China.
Abscisic acid (ABA) is an important plant hormone that plays significant roles in cold tolerance regulation. However, whether ABAimproves cold tolerance by increasing the activities of antioxidant enzymes in wheat remains unknown. In this study,the activities of antioxidant enzymes of the winter wheat variety 'dongnongdongmai 1' ('dn1')afterthe application of exogenous ABA under low temperature (0 degrees C, -10 degrees C, -20 degrees C, and -25 degrees C) were investigated. Results showed that cold stress significantly increased H2O2 and relative conductivity, whileABA significantly reduced this effect. ABA enhanced cold tolerance in both leaves and rhizomes at -10 degrees C and -20 degrees Cby increasing CAT, SOD, POD, APX, GR, DHAR, and MDHAR. However, this tolerance was weakenedat -25 degrees C with decreasing ASA, GSH, APX, DHAR, and MDHARthan at-10 degrees C and -20 degrees C.POD, GR, and DHARlevels peaked at -10 degrees C, while CAT, SOD, GSH, APX, and MDHAR content in rhizomes peaked at -20 degrees C. The rate of returning green was significantly increased after ABA treatment than in controls (93.5% vs 83.6 %). In 'dn1', rhizomes had a higher cold tolerance than leaves. Thereby, exogenous ABA could enhance cold tolerance byincreasing the activities of antioxidant enzymes.
PMID: 32619128
Plant Signal Behav , IF:1.671 , 2020 Jul , V15 (7) : P1770964 doi: 10.1080/15592324.2020.1770964
HOS15: A missing link that fine-tunes ABA signaling and drought tolerance in Arabidopsis.
Department of Biomedical Science & Engineering, Konkuk University , Seoul, South Korea.
Among the phytohormones, abscisic acid (ABA) specifically regulates plant adaptation to osmotic stresses, such as drought and high salinity, by controlling the internal water status in plants. A signi fi cant accumulation of ABA occurs in response to conditions of water de fi cit; this is followed by a sophisticated signaling relay, known as the ABA signaling pathway, which decreases the rate of transpiration through stomatal closure, thereby suppressing photosynthetic activity. Snf1-related kinases (SnRK2s) are the major components regulating the ABA signaling pathway. Of these, SnRK2.6 (OST1) and SnRK2.3 are negatively regulated by HOS15 (HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE15), in an ABA-dependent manner, to cease the signaling relay. HOS15 is a WD40-repeat protein that regulates several physiological processes, including plant growth and development, freezing stress responses, and ABA signaling. Here, we provide a brief overview of the functional importance of HOS15 in the regulation of ABA signaling and drought stress.
PMID: 32425099