Plant Cell , IF:9.618 , 2020 May doi: 10.1105/tpc.19.00716
Genome-wide Characterization of DNase I-hypersensitive Sites and Cold Response Regulatory Landscapes in Grasses.
Fujian Agriculture and Forestry University CITY: Fuzhou China [CN].; Quantitative Life Science Initiative, Center for Plant Science Innovation, Department of Agronomy and Horticulture, University of Nebraska-Lincoln CITY: Lincoln STATE: NE United States Of America [US].; University of Nebraska CITY: Lincoln STATE: NE POSTAL_CODE: 68516 United States Of America [US].; Fujian Agriculture and Forestry University CITY: Fuzhou STATE: Fujian POSTAL_CODE: 350002 China [CN].; Fujian Agriculture and Forestry University CITY: Fuzhou China [CN] kwang@fafu.edu.cn.
Deep sequencing of DNase-I treated chromatin (DNase-seq) can be used to identify DNase I-hypersensitive sites (DHSs) and facilitates genome-scale mining of de novo cis-regulatory DNA elements. Here, we adapted DNase-seq to generate genome-wide maps of DHSs using control and cold-treated leaf, stem, and root tissues of three widely studied grass species: Brachypodium distachyon, foxtail millet (Setaria italica), and sorghum (Sorghum bicolor). Functional validation demonstrated that 12 of 15 DHSs drove reporter gene expression in transiently transgenic B. distachyon protoplasts. DHSs under both normal and cold treatment substantially differed among tissues and species. Intriguingly, the putative DHS-derived transcription factors (TFs) are largely co-located among tissues and species and include 17 ubiquitous motifs covering all grass taxa and all tissues examined in this study. This feature allowed us to reconstruct a regulatory network that responds to cold stress. Ethylene-responsive TFs SHINE3, ERF2, and ERF9 occurred frequently in cold feedback loops in the tissues examined, pointing to their possible roles in the regulatory network. Overall, we provide experimental annotation of 322,713 DHSs and 93 derived cold-response TF-binding motifs in multiple grasses, which could serve as a valuable resource for elucidating the transcriptional networks that function in the cold-stress response and other physiological processes.
PMID: 32471863
Food Chem , IF:6.306 , 2020 May , V312 : P125904 doi: 10.1016/j.foodchem.2019.125904
Sucrose degradation pathways in cold-induced sweetening and its impact on the non-enzymatic darkening in sweet potato root.
Departamento de Biologia Vegetal, Universidade Federal de Vicosa, Vicosa 36570-900, Minas Gerais, Brazil. Electronic address: nicolas.araujo@ufv.br.; Departamento de Fitotecnia, Universidade Federal de Vicosa, Vicosa 36570-900, Minas Gerais, Brazil.; Departamento de Biologia Vegetal, Universidade Federal de Vicosa, Vicosa 36570-900, Minas Gerais, Brazil.
This study investigated sucrose catabolism during cold-induced sweetening (CIS) and its impact on the quality of sweet potato chips of cultivars with varied levels of tolerance to cold during storage at 6 and 13 degrees C. In contrast to cultivar Beauregard, cultivar BRS Rubissol and BRS Cuia were cold-sensitive exhibiting intense symptoms of chilling injury at 6 degrees C. CIS in the sensitive cultivars BRS Rubissol and BRS Cuia was characterized by low accumulation of reducing sugar (RS), high non-reducing sugars content, low invertase activity and high sucrose synthase (SuSy) activity. In the tolerant cultivar Beauregard, the high content of RS was due to high invertases activity. In the three cultivars, the darkening of chips was more influenced by the non-reducing sugars, instead of RS. Our results suggest that SuSy was induced by cold stress in cold-sensitive cultivar, but did not contribute to the CIS in sweet potato.
PMID: 31901701
Plant J , IF:6.141 , 2020 May doi: 10.1111/tpj.14848
AKR2A interacts with KCS1 to improve VLCFAs contents and chilling tolerance of Arabidopsis thaliana.
State Key Laboratory for Quality and Safety of Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.; Department of Botany St Joseph's College (Autonomous), Bengaluru, 560027, India.; Tianjin University of Science & Technology, Hexi District, Tianjin, 300457, China.; Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
Arabidopsis thaliana AKR2A plays an important role in plant responses to cold stress. However, its exact function in plant resistance to cold stress remains unclear. In the present study, we found that the contents of very long-chain fatty acids (VLCFAs) in akr2a mutants were decreased, and the expression level of KCS1 was also reduced. Overexpression of KCS1 in the akr2a mutants could enhance VLCFAs contents and chilling tolerance. Yeast-2-hybrid and bimolecular fluorescence complementation (BIFC) results showed that the transmembrane motif of KCS1 interacts with the PEST motif of AKR2A both in vitro and in vivo. Overexpression of KCS1 in akr2a mutants rescued akr2a mutant phenotypes, including chilling sensitivity and a decrease of VLCFAs contents. Moreover, the transgenic plants co-overexpressing AKR2A and KCS1 exhibited a greater chilling tolerance than the plants overexpressing AKR2A or KCS1 alone, as well as the wild-type. AKR2A knockdown and kcs1 knockout mutants showed the worst performance under chilling conditions. These results indicate that AKR2A is involved in chilling tolerance via an interaction with KCS1 to affect VLCFA biosynthesis in Arabidopsis.
PMID: 32433816
J Exp Bot , IF:5.908 , 2020 May doi: 10.1093/jxb/eraa254
The beta-ketoacyl-CoA synthase GhKCS13 regulates the cold response in cotton by modulating lipid and oxylipin biosynthesis.
Hubei Academy of Agricultural Sciences, Wuhan, Hubei, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China.; State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
Cold stress is a key environmental factor affecting plant development and productivity. In this study, 5239 differentially expressed genes (DEGs) were detected by RNA-seq in two different cultivars after cold stress treatment. Among which GhKCS13 was found involved in the response to cold stress in cotton. GhKCS13-overexpressing transgenic cotton plants showed increased sensitivity to cold stress, demonstrating an important role of GhKCS13 in regulating the response to cold stress. KEGG analysis of 418 DEGs in both GhKCS13-overexpressing and RNAi lines after 4 treatment revealed that lipid biosynthesis and linoleic acid metabolism were related to cold stress. ESI-MS/MS analysis showed that overexpressing GhKCS13 led to a modification of sphingolipid and glycerolipid composition in leaves, which might alter the fluidity of the cell membrane under cold conditions. In particular, the difference of jasmonic acid levels in GhKCS13 transgenic lines suggests JA might mediate cold stress response, together with lysophospholipids. Our results suggest that overexpressing GhKCS13 likely causes remodeling of lipids in the ER and oxylipin JA biosynthesis in chloroplasts, which might account for the increased sensitivity to cold stress in the transgenic cotton. Complex interactions between lipid components, lipid signaling molecules, and JA appear to determine the response to cold stress in cotton.
PMID: 32443155
J Exp Bot , IF:5.908 , 2020 May doi: 10.1093/jxb/eraa215
Alterations of glycerolipidome induced by molybdenum conferred drought tolerance of wheat.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.; Microelement Research Center, Huazhong Agricultural University, Wuhan, China.; Department of Biology, University of Missouri, St. Louis, Missouri, USA.; Donald Danforth Plant Science Center, St. Louis, Missouri, USA.
Molybdenum (Mo), an essential microelement for plant growth, plays important roles in multiple metabolic and physiological processes, including wheat responses to drought and cold stress. Lipids also have crucial roles in plant adaption to abiotic stress. This study was undertaken to determine the Mo-induced lipid changes associated with Mo-enhanced drought tolerance in wheat using glycerolipidomic and transcriptomic analyses. Mo treatments increased transcript level of genes involved in fatty acid and glycerolipid biosynthesis and desaturation, but suppressed the expression of genes in oxylipin production in wheat. Wheat plants supplemented with Mo displayed higher content of monogalactosyldiacyglycerol (MGDG), digalactosyldoacylglycerol (DGDG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE) and phosphatidylcholine (PC) with increased unsaturation. The level of MGDG, DGDG, PC and PG increased under polyethylene glycol 6000-simulated drought stress (PSD), with varied magnitudes in the presence and absence of Mo. Mo increased accumulations of the most abundant glycerolipids species of C36:6, C34:4, C34:3 by increasing gene expressions of desaturation under PSD, which contributed to maintaining fluidity of membranes. In addition, Mo attenuated the decrease in DGDG/MGDG and PC/PE ratios under simulated drought. Those lipid changes in Mo-treated wheat would contribute to maintaining the integrity of membranes and protecting photosynthetic apparatus, together enhancing drought tolerance of wheat.
PMID: 32369576
J Exp Bot , IF:5.908 , 2020 May , V71 (9) : P2573-2584 doi: 10.1093/jxb/eraa036
The contribution of cis- and trans-acting variants to gene regulation in wild and domesticated barley under cold stress and control conditions.
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466 Seeland, Germany.; German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, D-04103 Leipzig, Germany.
Barley, like other crops, has experienced a series of genetic changes that have impacted its architecture and growth habit to suit the needs of humans, termed the domestication syndrome. Domestication also resulted in a concomitant bottleneck that reduced sequence diversity in genes and regulatory regions. Little is known about regulatory changes resulting from domestication in barley. We used RNA sequencing to examine allele-specific expression in hybrids between wild and domesticated barley. Our results show that most genes have conserved regulation. In contrast to studies of allele-specific expression in interspecific hybrids, we find almost a complete absence of trans effects. We also find that cis regulation is largely stable in response to short-term cold stress. Our study has practical implications for crop improvement using wild relatives. Genes regulated in cis are more likely to be expressed in a new genetic background at the same level as in their native background.
PMID: 31989179
J Exp Bot , IF:5.908 , 2020 May , V71 (9) : P2723-2739 doi: 10.1093/jxb/eraa025
Glycosyltransferase OsUGT90A1 helps protect the plasma membrane during chilling stress in rice.
Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.; National Sweet Potato Improvement Center, Sweet Potato Research Institute, Xuzhou, P.R. China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China.
Due to its subtropical origins, rice (Oryza sativa) is sensitive to low-temperature stress. In this study, we identify LOC_Os04g24110, annotated to encode the UDP-glycosyltransferase enzyme UGT90A1, as a gene associated with the low-temperature seedling survivability (LTSS) quantitative trait locus qLTSS4-1. Differences between haplotypes in the control region of OsUGT90A1 correlate with chilling tolerance phenotypes, and reflect differential expression between tolerant and sensitive accessions rather than differences in protein sequences. Expression of OsUGT90A1 is initially enhanced by low temperature, and its overexpression helps to maintain membrane integrity during cold stress and promotes leaf growth during stress recovery, which are correlated with reduced levels of reactive oxygen species due to increased activities of antioxidant enzymes. In addition, overexpression of OsUGT90A1 in Arabidopsis improves freezing survival and tolerance to salt stress, again correlated with enhanced activities of antioxidant enzymes. Overexpression of OsUGT90A1 in rice decreases root lengths in 3-week-old seedlings while gene-knockout increases the length, indicating that its differential expression may affect phytohormone activities. We conclude that higher OsUGT90A1 expression in chilling-tolerant accessions helps to maintain cell membrane integrity as an abiotic stress-tolerance mechanism that prepares plants for the resumption of growth and development during subsequent stress recovery.
PMID: 31974553
Int J Mol Sci , IF:4.556 , 2020 May , V21 (11) doi: 10.3390/ijms21113857
Genome-Wide Characterization of GRAS Family and Their Potential Roles in Cold Tolerance of Cucumber (Cucumis sativus L.).
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, China.; College of Life Science and Technology, HongHe University, Mengzi 661100, China.
Cucumber (Cucumis sativus L.) is one of the most important cucurbit vegetables but is often subjected to stress during cultivation. GRAS (gibberellic acid insensitive, repressor of GAI, and scarecrow) genes encode a family of transcriptional factors that regulate plant growth and development. In the model plant Arabidopsis thaliana, GRAS family genes function in formation of axillary meristem and root radial structure, phytohormone (gibberellin) signal transduction, light signal transduction and abiotic/biological stress. In this study, a gene family was comprehensively analyzed from the aspects of evolutionary tree, gene structure, chromosome location, evolutionary and expression pattern by means of bioinformatics; 37 GRAS gene family members have been screened from cucumber. We reconstructed an evolutionary tree based on multiple sequence alignment of the typical GRAS domain and conserved motif sequences with those of other species (A. thaliana and Solanum lycopersicum). Cucumber GRAS family was divided into 10 groups according to the classification of Arabidopsis and tomato genes. We conclude that tandem and segmental duplication have played important roles in the expansion and evolution of the cucumber GRAS (CsaGRAS) family. Expression patterns of CsaGRAS genes in different tissues and under cold treatment, combined with gene ontology annotation and interaction network analysis, revealed potentially different functions for CsaGRAS genes in response to cold tolerance, with members of the SHR, SCR and DELLA subfamilies likely playing important roles. In conclusion, this study provides valuable information and candidate genes for improving cucumber tolerance to cold stress.
PMID: 32485801
Ann Bot , IF:4.005 , 2020 May , V125 (6) : P891-904 doi: 10.1093/aob/mcz211
Variation in seed traits among Mediterranean oaks in Tunisia and their ecological significance.
Laboratoire d'Ecologie Forestiere, INRGREF Tunis, Rue Hedi EL Karray El Menzah IV, BP 10, 2080 Ariana, Tunisia.; Faculte des Sciences de Bizerte, Universite de Carthage, 7021 Jarzouna, Tunisia.; IRD, Universite Montpellier, UMR DIADE, BP 64501, 34394 Montpellier, France.; IRD, CNRS, Universite Montpellier, MIVEGEC, Montpellier, France.
BACKGROUND AND AIMS: Oaks are the foundation and dominant tree species of most Mediterranean forests. As climate models predict dramatic changes in the Mediterranean basin, a better understanding of the ecophysiology of seed persistence and germination in oaks could help define their regeneration niches. Tunisian oaks occupy distinct geographical areas, which differ in their rainfall and temperature regimes, and are thus a valuable model to investigate relationships between seed traits and species ecological requirements. METHODS: Seed morphological traits, desiccation sensitivity level, lethal freezing temperature, embryonic axis and cotyledon sugar and lipid composition, and seed and acorn germination rates at various constant temperatures were measured in Quercus canariensis, Q. coccifera, Q. ilex and Q. suber, using seeds sampled in 22 Tunisian woodlands. KEY RESULTS: Only faint differences were observed for desiccation sensitivity in the oak species studied. By contrast, the species differed significantly in sensitivity to freezing, germination rates at low temperature and base temperature. Quercus ilex and Q. canariensis, which occur at high elevations where frost events are frequent, showed the lowest freezing sensitivity. A significant correlation was found between hexose contents in the embryonic axis and freezing tolerance. Significant interspecific differences in the time for seeds to germinate and the time for the radicle to pierce the pericarp were observed. The ratio of pericarp mass to acorn mass differed significantly among the species and was negatively correlated with the acorn germination rate. Quercus coccifera, which is frequent in warm and arid environments, showed the highest acorn germination rate and synchrony. CONCLUSIONS: Seed lethal temperature, seed germination time at low temperatures, the ratio of pericarp mass to acorn mass and the embryonic axis hexose content appeared to be key functional traits that may influence the geographical ranges and ecological requirements of Mediterranean oaks in Tunisia.
PMID: 31904087
Plant Physiol Biochem , IF:3.72 , 2020 May , V154 : P316-327 doi: 10.1016/j.plaphy.2020.05.026
Cold acclimation and freezing tolerance in three Eucalyptus species: A metabolomic and proteomic approach.
EEA Concordia del INTA, Ruta 22 y vias del ferrocarril, Colonia Yerua, Entre Rios, Argentina. Electronic address: oberschelp.javier@inta.gob.ar.; Facultad de Agronomia de la Universidad de Buenos Aires (FAUBA), Av. San Martin 4453, CABA, Argentina.; EEA Concordia del INTA, Ruta 22 y vias del ferrocarril, Colonia Yerua, Entre Rios, Argentina.; Centro de Estudios Fotosinteticos y Bioquimicos (CEFOBI), Suipacha 531, Rosario, Santa Fe. Argentina.; Centro de Estudios Fotosinteticos y Bioquimicos (CEFOBI), Suipacha 531, Rosario, Santa Fe. Argentina. Electronic address: margarit@cefobi-conicet.gov.ar.
The ability of plants to cope with frost events relies on the physiological and molecular responses triggered by cold temperatures. This process, named acclimation, involves reprogramming gene expression in order to adjust metabolism. Planted Eucalyptus species are highly productive but most of them are frost sensitive. However, acclimation process varies among species and environmental conditions, promoting more or less frost damage in young plantations of frost-prone areas. To identify metabolites and proteins responsible for these differences, two acclimation regimes were imposed to seedling of Eucalyptus grandis Hill ex Maiden (Eg), Eucalyptus dunnii Maiden (Ed) and Eucalyptus benthamii Maiden Cambage (Eb), and leaves submitted to biochemical and molecular analyses. Further, seedlings were used for simulated frosts in order to test the acclimation status effect on frost tolerance. Eb showed higher frost tolerance than Ed and Eg under control and acclimation scenarios, possibly due to its higher accumulation of phenolics, anthocyanins and soluble sugars as well as lower levels of photosynthetic pigments and related proteins. Also, a rise in frost tolerance and in osmoprotectants and antioxidants was observed for all the species due to cold acclimation treatment. Interestingly, metabolic profiles differed among species, suggesting different mechanisms to endure frosts and, probably, different requirements for cold acclimation. Shotgun proteomics reinforced differences and commonalities and supported metabolome observations. An in depth understanding of these responses could help to safeguard planted forests productivity through breeding of tolerant genetic material.
PMID: 32593088
Plant Sci , IF:3.591 , 2020 May , V294 : P110432 doi: 10.1016/j.plantsci.2020.110432
The ethylene responsive factor CdERF1 from bermudagrass (Cynodon dactylon) positively regulates cold tolerance.
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan Hubei 430074, China; State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, China.; Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan Hubei 430074, China.; College of Animal Science and Technology, Yangzhou University, Yangzhou Jiangsu 225009, China.; Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan Hubei 430074, China. Electronic address: chenliang1034@126.com.; Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan Hubei 430074, China; Shandong Coastal Salinity Tolerant Grass Engineering and Technology Research Center, Ludong University, Yantai 264025, China. Electronic address: turfcn@qq.com.
Cold stress is one of the major environmental factors that limit growth and utilization of bermudagrass [Cynodon dactylon (L.) Pers], a prominent warm-season turfgrass. However, the molecular mechanism of cold response in bermudagrass remains largely unknown. In this study, we characterized a cold-responsive ERF (ethylene responsive factor) transcription factor, CdERF1, from bermudagrass. CdERF1 expression was induced by cold, drought and salinity stresses. The CdERF1 protein was nucleus-localized and encompassed transcriptional activation activity. Transgenic Arabidopsis plants overexpressing CdERF1 showed enhanced cold tolerance, whereas CdERF1-underexpressing bermudagrass plants via virus induced gene silencing (VIGS) method exhibited reduced cold resistance compared with control, respectively. Under cold stress, electrolyte leakage (EL), malondialdehyde (MDA), H2O2 and O2(-) contents were reduced, while the activities of SOD and POD were elevated in transgenic Arabidopsis. By contrast, these above physiological indicators in CdERF1-underexpressing bermudagrass exhibited the opposite trend. To further explore the possible molecular mechanism of bermudagrass cold stress response, the RNA-Seq analyses were performed. The result indicated that overexpression of CdERF1 activated a subset of stress-related genes in transgenic Arabidopsis, such as CBF2, pEARLI1 (lipid transfer protein), PER71 (peroxidase) and LTP (lipid transfer protein). Interestingly, under-expression of CdERF1 suppressed the transcription of many genes in CdERF1-underexpressing bermudagrass, also including pEARLI1 (lipid transfer protein) and PER70 (peroxidase). All these results revealed that CdERF1 positively regulates plant cold response probably by activating stress-related genes, PODs, CBF2 and LTPs. This study also suggests that CdERF1 may be an ideal candidate in the effort to improve cold tolerance of bermudagrass in the further molecular breeding.
PMID: 32234227
BMC Plant Biol , IF:3.497 , 2020 May , V20 (1) : P240 doi: 10.1186/s12870-020-02450-z
Comparative transcriptome profiling reveals cold stress responsiveness in two contrasting Chinese jujube cultivars.
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.; Institute of Crop, Wuhan Academy of Agricultural Sciences, Wuhan, 430074, China.; Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China. xmpang@bjfu.edu.cn.
BACKGROUND: Low temperature is a major factor influencing the growth and development of Chinese jujube (Ziziphus jujuba Mill.) in cold winter and spring. Little is known about the molecular mechanisms enabling jujube to cope with different freezing stress conditions. To elucidate the freezing-related molecular mechanism, we conducted comparative transcriptome analysis between 'Dongzao' (low freezing tolerance cultivar) and 'Jinsixiaozao' (high freezing tolerance cultivar) using RNA-Seq. RESULTS: More than 20,000 genes were detected at chilling (4 degrees C) and freezing (- 10 degrees C, - 20 degrees C, - 30 degrees C and - 40 degrees C) stress between the two cultivars. The numbers of differentially expressed genes (DEGs) between the two cultivars were 1831, 2030, 1993, 1845 and 2137 under the five treatments. Functional enrichment analysis suggested that the metabolic pathway, response to stimulus and catalytic activity were significantly enriched under stronger freezing stress. Among the DEGs, nine participated in the Ca(2+) signal pathway, thirty-two were identified to participate in sucrose metabolism, and others were identified to participate in the regulation of ROS, plant hormones and antifreeze proteins. In addition, important transcription factors (WRKY, AP2/ERF, NAC and bZIP) participating in freezing stress were activated under different degrees of freezing stress. CONCLUSIONS: Our research first provides a more comprehensive understanding of DEGs involved in freezing stress at the transcriptome level in two Z. jujuba cultivars with different freezing tolerances. These results may help to elucidate the molecular mechanism of freezing tolerance in jujube and also provides new insights and candidate genes for genetically enhancing freezing stress tolerance.
PMID: 32460709
BMC Plant Biol , IF:3.497 , 2020 May , V20 (1) : P238 doi: 10.1186/s12870-020-02427-y
LcMYB4, an unknown function transcription factor gene from sheepgrass, as a positive regulator of chilling and freezing tolerance in transgenic Arabidopsis.
Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing, China.; Guangdong Provincial Key Laboratory for Crop Germplasm Resources Preservation and Utilization, Agro-biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Guangzhou, China.; College of management science and engineering, Hebei University of Economics and Business, Shijiazhuang, China.; Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing, China. lqcheng@ibcas.ac.cn.; Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing, China. liugs@ibcas.ac.cn.
BACKGROUND: Sheepgrass (Leymus chinensis (Trin.) Tzvel) is a perennial forage grass that can survive extreme freezing winters (- 47.5 degrees C) in China. In this study, we isolated an unknown function MYB transcription factor gene, LcMYB4, from sheepgrass. However, the function of LcMYB4 and its homologous genes has not been studied in other plants. RESULTS: The expression of the LcMYB4 gene was upregulated in response to cold induction, and the LcMYB4 fusion protein was localized in the nucleus, with transcriptional activation activity. Biological function analysis showed that compared with WT plants, LcMYB4-overexpressing Arabidopsis presented significantly increased chilling and freezing tolerance as evidenced by increased germination rate, survival rate, and seed setting rate under conditions of low temperature stress. Furthermore, LcMYB4-overexpressing plants showed increased soluble sugar content, leaf chlorophyll content and superoxide dismutase activity but decreased malondialdehyde (MDA) under chilling stress. Moreover, the expression of the CBF1, KIN1, KIN2 and RCI2A genes were significantly upregulated in transgenic plants with chilling treatment. These results suggest that LcMYB4 overexpression increased the soluble sugar content and cold-inducible gene expression and alleviated oxidative damage and membrane damage, resulting in enhanced cold resistance in transgenic plants. Interestingly, our results showed that the LcMYB4 protein interacts with fructose-1,6-bisphosphate aldolase protein1 (LcFBA1) and that the expression of the LcFBA1 gene was also upregulated during cold induction in sheepgrass, similar to LcMYB4. CONCLUSION: Our findings suggest that LcMYB4 encodes MYB transcription factor that plays a positive regulatory role in cold stress.
PMID: 32460695
J Plant Physiol , IF:3.013 , 2020 May , V248 : P153138 doi: 10.1016/j.jplph.2020.153138
A DEAD-box RNA helicase TCD33 that confers chloroplast development in rice at seedling stage under cold stress.
College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.; The Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan Cun Street, Beijing 100081, China.; Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, 1000 Jingqi Road, Fengxian District, Shanghai 201403, China.; National Institute of Agricultural Science, Jeon Ju, 560-500 South Korea.; College of Life Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: dzlin@shnu.edu.cn.; College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; Shanghai Key Laboratory of Plant Molecular Sciences, Shanghai 200234, China. Electronic address: dong@shnu.edu.cn.
Cold stress is one of the most common unfavorable environmental factors affecting the growth, development, and survival of plants. The DEAD-box RNA helicases play important roles in all types of processes of RNA metabolism. However, the function of DEAD-box RNA helicase under cold stress is poorly explored in plants, especially in rice. This study reported the identification of a novel rice thermo-sensitive chlorophyll-deficient mutant, tcd33, which displayed an albino phenotype before the four-leaf stage, then withered and eventually died at 20 degrees C, while wild-type plants exhibited normal green coloration at 32 degrees C. The tcd33 seedlings also exhibited less chlorophyll contents and severe defects of chloroplast structure under 20 degrees C condition. Map-based cloning and complementation experiments suggested that TCD33 encodes a chloroplast-located DEAD-box RNA helicase protein. The transcript expression level of TCD33 indicated that the genes related to chlorophyll (Chl) biosynthesis, photosynthesis, and chloroplast development in tcd33 mutants were down-regulated at 20 degrees C, while the down-regulated genes were nearly recovered to or slightly higher than the WT level at 32 degrees C. Together, our results suggest that the cold-inducible TCD33 is essential for early chloroplast development and is important for cold-responsive gene regulation and cold tolerance in rice.
PMID: 32213379
Funct Plant Biol , IF:2.617 , 2020 May , V47 (6) : P544-557 doi: 10.1071/FP19267
LncRNA improves cold resistance of winter wheat by interacting with miR398.
College of Life Science, Northeast Agricultural University, Harbin 15000, Heilongjiang, China.; College of Life Science, Northeast Agricultural University, Harbin 15000, Heilongjiang, China; and Corresponding authors. Email: xuqinghua@neau.edu.cn; cangjing2003@163.com.
One of the important functions of long non-coding RNA (lncRNA) is to be competing endogenous RNAs (ceRNAs). As miR398 is reported to respond to different stressors, it is necessary to explore its relationship with lncRNA in the cold resistance mechanism of winter wheat. Tae-miR398-precursor sequence was isolated from the winter wheat (Triticum aestivum). RLM-RACE verified that tae-miR398 cleaved its target CSD1. Quantitative detection at 5 degrees C, -10 degrees C and -25 degrees C showed that the expression of tae-miR398 decreased in response to low temperatures, whereas CSD1 showed an opposite expression pattern. LncR9A, lncR117 and lncR616 were predicted and verified to interact with miR398. tae-miR398 and three lncRNAs were transferred into Arabidopsis thaliana respectively. The lncR9A were transferred into Brachypodium distachyom. Transgenic plants were cultivated at -8 degrees C and assessed for the expression of malondialdehyde, chlorophyll, superoxide dismutase and miR398-lncRNA-target mRNA. The results demonstrate that tae-miR398 regulates low temperature tolerance by downregulating its target, CSD1. lncRNA regulates the expression of CSD1 indirectly by competitively binding miR398, which, in turn, affects the resistance of Dn1 to cold. miR398-regulation triggers a regulatory loop that is critical to cold stress tolerance in wheat. Our findings offer an improved strategy to crop plants with enhanced stress tolerance.
PMID: 32345432
Plant Biol (Stuttg) , IF:2.167 , 2020 May , V22 (3) : P450-458 doi: 10.1111/plb.13095
An eggplant SmICE1a gene encoding MYC-type ICE1-like transcription factor enhances freezing tolerance in transgenic Arabidopsis thaliana.
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China.
Low temperature is a crucial environmental factor affecting the quality and production of eggplant. Therefore, it is necessary to explore the molecular mechanisms of low temperature response. We isolated an ICE (inducer of CBF expression) gene from Solanum melongena, named SmICE1a. We then analysed structure, transcriptional activity and expression patterns of SmICE1a. Moreover, we also expressed SmICE1a in Arabidopsis thaliana. Bioinformatics and expression analysis showed that SmICE1a has a typical S-rich motif, ZIP region, bHLH and ACT-like domain. The gene SmICE1a had transcriptional activity in yeast and was localized to the nucleus following transient expression in tobacco leaves, which suggests that SmICE1a is a transcription factor. A dual-LUC assay revealed that SmICE1a can enhance expression of SmCBF. Overexpression of SmICE1a in Arabidopsis increased freezing tolerance and caused multiple biochemical changes: transgenic lines have higher proline content and lower electrolyte leakage and malondialdehyde than the wild type in cold conditions. The expression of AtCBF and their target genes, AtCOR15A, AtCOR47, AtKIN1 and AtRD29A, were up-regulated in SmICE1a-overexpressing plants under low temperatures. Based on these results, we suggest that SmICE1a plays an important role in cold response, which may help to understand the cold response mechanism in eggplant and could be used to enhance cold tolerance of eggplant in future.
PMID: 32009285
Biochem Genet , IF:2.027 , 2020 May doi: 10.1007/s10528-020-09969-8
Genome-Wide Identification and Analysis of the Growth-Regulating Factor (GRF) Gene Family and GRF-Interacting Factor Family in Triticum aestivum L.
State Key Laboratory of Crop Stress Biology in Arid Areas and College of Agronomy, Northwest A&F University, 3 Taicheng Rd, Yangling, 712100, Shaanxi, People's Republic of China.; State Key Laboratory of Crop Stress Biology in Arid Areas and College of Agronomy, Northwest A&F University, 3 Taicheng Rd, Yangling, 712100, Shaanxi, People's Republic of China. liliqun@nwsuaf.edu.cn.
Growth-regulating factors (GRFs) are unique transcription factors in plants. GRFs can interact with SNH (SYT N-terminal homology) domains in GRF-interacting factor (GIF) proteins via the N-terminal QLQ (Gln, Leu, Gln) domain to form functional complexes and participate in the regulation of downstream gene expression. In this study, we systematically identified the GRF gene family and GIF gene family in wheat and its relatives comprising Triticum urartu, Triticum dicoccoides, and Aegilops tauschii. Thirty GRF gene members are present in wheat, which are distributed on 12 chromosomes and they have 2-5 protein-coding regions. They all contain QLQ and WRC (Trp, Arg, Cys) conserved domains. Wheat possesses only eight members of the GIF gene family, which are distributed on six chromosomes. All wheat GIF (TaGIF) proteins have highly conserved SNH and QG (Gln, Gly) domains. The wheat GRF (TaGRF) gene family has 13 pairs of segmental duplication genes and no tandem duplication genes; the TaGIF gene family has two pairs of segmental duplication genes and no tandem duplication genes. It is speculated that segmental duplication events may be the main reason for the amplification of TaGRF gene family and TaGIF gene family. Based on published transcriptome data and qRT-PCR results of 8 TaGRF genes and 4 TaGIF genes, all of the genes responded strongly to osmotic stress, and the expression levels of TaGRF21 and TaGIF5 were also significantly upregulated under drought and cold stress conditions. The results obtained in this study may facilitate further investigations of the functions of TaGRF genes and TaGIF genes in order to identify candidate genes for use in stress-resistant wheat breeding programs.
PMID: 32399658
Physiol Mol Biol Plants , IF:2.005 , 2020 May , V26 (5) : P955-964 doi: 10.1007/s12298-020-00792-4
Photosynthetic activity of indica rice sister lines with contrasting cold tolerance.
1Programa de Pos-Graduacao em Botanica (PPGBot), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS Brazil.grid.8532.c0000 0001 2200 7498; 2Escola de Quimica e Alimentos, Universidade Federal do Rio Grande (FURG), Campus Santo Antonio da Patrulha, Rio Grande, RS Brazil.grid.411598.00000 0000 8540 6536; 3Programa de Pos-Graduacao em Biotecnologia (PPGBiotec), Centro de Ciencias Biologicas e da Saude (CCBS), Universidade do Vale do Taquari - Univates, Lajeado, RS Brazil.grid.441846.b0000 0000 9020 9633
Incidence of cold during early stages is an obstacle for the growing progress of rice plants. Cold stress has strong negative effects on photosynthetic activity. Previously, our group evaluated plant survival of 90 indica rice genotypes after cold treatment. Two sister lines were characterized as cold-tolerant and cold-sensitive. Transcriptomic analyses of the same genotypes had indicated differential expression of genes related to photosynthesis. Previous work with japonica rice had suggested that cold sensitivity was more related to photosystem II (PSII) than to photosystem I (PSI). Using our previously identified contrasting genotypes, we investigated the role of specific steps of the photosynthetic process in cold tolerance/sensitivity of indica rice plants during and after (recovery period) cold exposure. During both cold treatment and recovery period, the photochemical activity (including PSII and PSI) presented higher levels in the low temperature-tolerant genotype, when compared with the sensitive one. The higher photochemical efficiency during the cold treatment appears to be related to a lower fraction of reduced QA (-) in PSII. We also observed lower transpiration rates and higher water use efficiency in the cold-tolerant genotype, due to stomatal closure. After the recovery period, the higher efficiency in the cold-tolerant genotype seems to be related to a lower fraction of reduced QA (-) and a larger pool of final electron acceptors at the PSI. This work uncovered changes in photosynthetic performance including both photosystems and improved water use efficiency which may be important components of cold tolerance mechanisms in indica rice.
PMID: 32377045
3 Biotech , IF:1.798 , 2020 May , V10 (5) : P225 doi: 10.1007/s13205-020-02197-2
Isolation and functional validation of stress tolerant EaMYB18 gene and its comparative physio-biochemical analysis with transgenic tobacco plants overexpressing SoMYB18 and SsMYB18.
1Molecular Biology and Genetic Engineering Division, Vasantdada Sugar Institute, Manjari (Bk), Tal. Haveli, Pune, Maharashtra 412307 India.grid.32056.320000 0001 2190 9326; Vasantrao Naik College of Agricultural Biotechnology, Waghapur Road, Yavatmal, Maharashtra 445001 India.; 5Department of Biotechnology, Shivaji University, Kolhapur, Maharashtra 416004 India.grid.412574.10000 0001 0709 7763; ICAR-Directorate of Floriculture Research, College of Agricultural Campus, Shivaji Nagar, Pune, Maharashtra 411005 India.; Department of Botany, BJS Arts, Science and Commerce College, Bakori Phata, Wagholi, Pune, Maharashtra 412207 India.
MYB transcription factors are one of the most important mediators for the survival of plants under multiple stress responses. In the present study, EaMYB18, encoding a single R3 repeat MYB DNA binding domain was isolated from stress-tolerant wild relative species of sugarcane Erianthus arundinaceus. In silico analysis of 948 bp coding mRNA sequence of EaMYB18 exhibited the presence of four exons and three introns. Further, the EaMYB18 gene was transformed in tobacco and its stable inheritance was confirmed through antibiotic resistance screening, PCR amplification and Southern hybridization blotting. Results of the estimation of MDA, proline, total chlorophyll and antioxidant activities of EaMYB18 transgenic tobacco lines exhibited least oxidative damage under drought and cold stress over the untransformed ones, the over-expression of EaMYB18 has improved drought and cold stress tolerance ability in tobacco. The comparative physiological and biochemical analysis of transgenic tobacco plants overexpressing SoMYB18, SsMYB18 and EaMYB18, revealed that the EaMYB18 and SsMYB18 transgenic plants demonstrated effective tolerance to drought and cold stresses, while SoMYB18 showed improved tolerance to salt stress alone. Amongst these three genes, EaMYB18 displayed the highest potential for drought and cold stress tolerances as compared to SoMYB18 and SsMYB18 genes.
PMID: 32373417
3 Biotech , IF:1.798 , 2020 May , V10 (5) : P209 doi: 10.1007/s13205-020-02203-7
Heterologous expression of an Agropyron cristatum SnRK2 protein kinase gene (AcSnRK2.11) increases freezing tolerance in transgenic yeast and tobacco.
1College of Agriculture, Inner Mongolia University for Nationalities, Tongliao, 028042 China.grid.411647.10000 0000 8547 6673; 2College of Life Science, Inner Mongolia University for Nationalities, Tongliao, 028042 China.grid.411647.10000 0000 8547 6673
The sucrose non-fermenting-1 related protein kinase 2 (SnRK2) family plays an important role in the response to abiotic stress. To characterize the function of the SnRK2 gene from Agropyron cristatum in stress protection, we cloned the complete coding sequence of the AcSnRK2.11 gene from A. cristatum and generated AcSnRK2.11-overexpressing tobacco lines. The open reading frame of AcSnRK2.11 was 1083 bp in length and encoded a polypeptide of 360 amino acid residues. The sequence analysis results showed that AcSnRK2.11 contained conserved domains typified in SnRK2 protein kinases. Subcellular localization analysis showed that AcSnRK2.11 was located in the nucleus. AcSnRK2.11 was constitutively expressed in all of the examined tissues, and its transcription was induced by cold, dehydration, and salt stress, but not by abscisic acid treatment. Overexpression of the AcSnRK2.11 gene conferred freezing tolerance in yeast. AcSnRK2.11-overexpressing tobacco lines showed higher tolerance to freezing stress than did wild-type (WT) based on higher survival rates, lower malondialdehyde content and increased relative water content retention, chlorophyll yields, superoxide dismutase activities, reactive oxygen species content, peroxidase levels, and soluble carbohydrates under low-temperature conditions. The transcripts of NtDREB1, NtDREB2, NtERD10A, NtERD10B, NtERD10C, NtERD10D, NtMnSOD, NtCDPK15, and NtMPK9 in AcSnRK2.11-overexpressing tobacco lines were more abundant than in WT plants under low-temperature stress. These results suggest that AcSnRK2.11 may function as a regulatory factor associated with a cold-response pathway and could be used in plant breeding for cold resistance.
PMID: 32351867
J Biomol Struct Dyn , 2020 May : P1-10 doi: 10.1080/07391102.2020.1751295
Understanding the thermal response of rice eukaryotic transcription factor eIF4A1 towards dynamic temperature stress: insights from expression profiling and molecular dynamics simulation.
Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India.; Distributed Information Centre (DIC), Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam, India.; Department of Biochemistry, University of Cambridge, Cambridge, UK.; Department of Chemistry, Technical University of Denmark, Kgs. Lyngby, Denmark.
Eukaryotic translation initiation factors (eIFs) are the group of regulatory proteins that are involved in the initiation of translation events. Among them, eIF4A1, a member of the DEAD-box RNA helicase family, participates in a wide spectrum of activities which include, RNA splicing, ribosome biogenesis, and RNA degradation. It is well known that ATP-binding and subsequent hydrolysis activities are crucial for the functionality of such helicases. Although the stress-responsive upregulation of eIF4A1 has been reported in plants during stress, it is difficult to anticipate the functionality of the corresponding protein product. Therefore, to understand the activity of eIF4A1 in rice in response to temperature stress, we first conducted an expression analysis of the gene and further investigated the structural stability of the eIF4A1-ATP/Mg(2+) complex through molecular dynamics (MD) simulations at different temperature conditions (277 K, 300 K, and 315 K). Our results demonstrated a three to fourfold increased expression of rice eIF4A1 both in root and shoot at 42 degrees C compared to control. Furthermore, the MD simulation portrayed strong ATP/Mg(2+) binding at a higher temperature in comparison to control and cold temperature. Overall, the increased expression pattern of eIF4A1 and strong ATP/Mg(2+) binding at higher temperature indicated the heat stress-tolerant capacity of the gene in rice. The results from our study will help in understanding the activity of gene and guide the researchers for screening of novel stress inducible candidate genes for the engineering of temperature stress tolerant plants.Communicated by Ramaswamy H. Sarma.
PMID: 32367760