Nat Commun , IF:12.121 , 2019 Oct , V10 (1) : P4810 doi: 10.1038/s41467-019-12781-7
Extracellular pyridine nucleotides trigger plant systemic immunity through a lectin receptor kinase/BAK1 complex.
Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.; Department of Plant Pathology, University of Florida, Gainesville, FL, 32611, USA.; Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL, 33850, USA.; Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32610, USA.; National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA.; Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA. zhlmou@ufl.edu.
Systemic acquired resistance (SAR) is a long-lasting broad-spectrum plant immunity induced by mobile signals produced in the local leaves where the initial infection occurs. Although multiple structurally unrelated signals have been proposed, the mechanisms responsible for perception of these signals in the systemic leaves are unknown. Here, we show that exogenously applied nicotinamide adenine dinucleotide (NAD(+)) moves systemically and induces systemic immunity. We demonstrate that the lectin receptor kinase (LecRK), LecRK-VI.2, is a potential receptor for extracellular NAD(+) (eNAD(+)) and NAD(+) phosphate (eNADP(+)) and plays a central role in biological induction of SAR. LecRK-VI.2 constitutively associates with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in vivo. Furthermore, BAK1 and its homolog BAK1-LIKE1 are required for eNAD(P)(+) signaling and SAR, and the kinase activities of LecR-VI.2 and BAK1 are indispensable to their function in SAR. Our results indicate that eNAD(+) is a putative mobile signal, which triggers SAR through its receptor complex LecRK-VI.2/BAK1 in Arabidopsis thaliana.
PMID: 31641112
Mol Plant , IF:12.084 , 2019 Oct , V12 (10) : P1408-1415 doi: 10.1016/j.molp.2019.06.006
BZR1 Family Transcription Factors Function Redundantly and Indispensably in BR Signaling but Exhibit BRI1-Independent Function in Regulating Anther Development in Arabidopsis.
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China; Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang 050024, China.; Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang 050024, China; State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, the Innovative Academy of Seed Design, Chinese Academy of Sciences, Shijiazhuang 050021, China.; Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China; Hebei Collaboration Innovation Center for Cell Signaling, Shijiazhuang 050024, China. Electronic address: tangwq@mail.hebtu.edn.cn.
BRASSINAZOLE-RESISTANT 1 family proteins (BZRs) are central transcription factors that govern brassinosteroid (BR)-regulated gene expression and plant growth. However, it is unclear whether there exists a BZR-independent pathway that mediates BR signaling. In this study, we found that disruption of all BZRs in Arabidopsis generated a hextuple mutant (bzr-h) displaying vegetative growth phenotypes that were almost identical to those of the null mutant of three BR receptors, bri1brl1brl3 (bri-t). By RNA sequencing, we found that global gene expression in bzr-h was unaffected by 2 h of BR treatment. The anthers of bzr-h plants were loculeless, but a similar phenotype was not observed in bri-t, suggesting that BZRs have a BR signaling-independent regulatory role in anther development. By real-time PCR and in situ hybridization, we found that the expression of SPOROCYTELESS (SPL), which encodes a transcription factor essential for anther locule development, was barely detectable in bzr-h, suggesting that BZRs regulate locule development by affecting SPL expression. Our findings reveal that BZRs are indispensable transcription factors required for both BR signaling and anther locule development, providing new insight into the molecular mechanisms underlying the microsporogenesis in Arabidopsis.
PMID: 31229643
Curr Opin Plant Biol , IF:8.356 , 2019 Oct , V51 : P105-113 doi: 10.1016/j.pbi.2019.06.006
Emerging roles of vascular brassinosteroid receptors of the BRI1-like family.
Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona 08193, Spain.; Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona 08193, Spain. Electronic address: ana.cano@cragenomica.es.
Brassinosteroids (BRs) are essential hormones for plant growth and development that are perceived at the plasma membrane by a group of Leucine-Rich Repeat Receptor-Like Kinases (LRR-RLKs) of the BRASSINOSTEROID INSENSITIVE 1 (BRI1) family. The BRI1 receptor was first discovered by genetic screenings based on the dwarfism of BR-deficient plants. There are three BRI1 homologs, named BRI1-like 1, 2 and 3 (BRLs), yet only BRL1 and BRL3 behave as functional BR receptors. Whereas the BRI1 pathway operates in the majority of cells to promote growth, BRL receptor signaling operates under specific spatiotemporal constraints. Despite a wealth of information on the BRI1 pathway, data on specific BRL pathways and their biological relevance is just starting to emerge. Here, we systematically compare BRLs with BRI1 to identify any differences that could account for specific receptor functions. Understanding how vascular and cell-specific BRL receptors orchestrate plant development and adaptation to the environment will help shed light on membrane signaling and cell communication in plants, while opening up novel possibilities to improve stress adaptation without penalizing growth.
PMID: 31349107
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (20) doi: 10.3390/ijms20205173
Melatonin Deficiency Confers Tolerance to Multiple Abiotic Stresses in Rice via Decreased Brassinosteroid Levels.
Department of Biotechnology, College of Agricultural and Life Sciences, Chonnam National University, Gwangju 61186, Korea. smilax@jnu.ac.kr.; Department of Biotechnology, College of Agricultural and Life Sciences, Chonnam National University, Gwangju 61186, Korea. kback@chonnam.ac.kr.
Melatonin has long been recognized as a positive signaling molecule and potent antioxidant in plants, which alleviates damage caused by adverse conditions such as salt, cold, and heat stress. In this study, we found a paradoxical role for melatonin in abiotic stress responses. Suppression of the serotonin N-acetyltransferase 2 (snat2) gene encoding the penultimate enzyme in melatonin biosynthesis led to simultaneous decreases in both melatonin and brassinosteroid (BR) levels, causing a semi-dwarf with erect leaf phenotype, typical of BR deficiency. Here, we further characterized snat2 rice in terms of grain morphology and abiotic stress tolerance, to determine whether snat2 rice exhibited characteristics similar to those of BR-deficient rice. As expected, the snat2 rice exhibited tolerance to multiple stress conditions including cadmium, salt, cold, and heat, as evidenced by decreased malondialdehyde (MDA) levels and increased chlorophyll levels, in contrast with SNAT2 overexpression lines, which were less tolerant to stress than wild type plants. In addition, the length and width of grain from snat2 plants were reduced relative to the wild type, which is reminiscent of BR deficiency in rice. Other melatonin-deficient mutant rice lines with suppressed BR synthesis (i.e., comt and t5h) also showed tolerance to salt and heat stress, whereas melatonin-deficient rice seedlings without decreased BR levels (i.e., tdc) failed to exhibit increased stress tolerance, suggesting that stress tolerance was increased not by melatonin deficiency alone, but by a melatonin deficiency-mediated decrease in BR.
PMID: 31635310
Int J Mol Sci , IF:4.556 , 2019 Oct , V20 (19) doi: 10.3390/ijms20194908
Abscisic Acid Represses Rice Lamina Joint Inclination by Antagonizing Brassinosteroid Biosynthesis and Signaling.
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. qfli@yzu.edu.cn.; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China. qfli@yzu.edu.cn.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. junyuelj@163.com.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. 15750556002@163.com.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. wufan_19941109@163.com.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China. tonghongning@caas.cn.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. wangjd1012@163.com.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. yvjiawen@outlook.com.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. cqzhang@yzu.edu.cn.; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China. cqzhang@yzu.edu.cn.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. xlfan@yzu.edu.cn.; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China. xlfan@yzu.edu.cn.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. qqliu@yzu.edu.cn.; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou 225009, China. qqliu@yzu.edu.cn.
Leaf angle is a key parameter that determines plant architecture and crop yield. Hormonal crosstalk involving brassinosteroid (BR) plays an essential role in leaf angle regulation in cereals. In this study, we investigated whether abscisic acid (ABA), an important stress-responsive hormone, co-regulates lamina joint inclination together with BR, and, if so, what the underlying mechanism is. Therefore, lamina joint inclination assay and RNA sequencing (RNA-Seq) analysis were performed here. ABA antagonizes the promotive effect of BR on leaf angle. Hundreds of genes responsive to both hormones that are involved in leaf-angle determination were identified by RNA-Seq and the expression of a gene subset was confirmed using quantitative real-time PCR (qRT-PCR). Results from analysis of rice mutants or transgenic lines affected in BR biosynthesis and signaling indicated that ABA antagonizes the effect of BR on lamina joint inclination by targeting the BR biosynthesis gene D11 and BR signaling genes GSK2 and DLT, thus forming a multi-level regulatory module that controls leaf angle in rice. Taken together, our findings demonstrate that BR and ABA antagonistically regulate lamina joint inclination in rice, thus contributing to the elucidation of the complex hormonal interaction network that optimizes leaf angle in rice.
PMID: 31623350
Viruses , IF:3.816 , 2019 Oct , V11 (11) doi: 10.3390/v11111009
The C4 Protein from Tomato Yellow Leaf Curl Virus Can Broadly Interact with Plant Receptor-Like Kinases.
Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. borja@psc.ac.cn.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. zhangdan@sibs.ac.cn.; University of the Chinese Academy of Sciences, Beijing 100049, China. zhangdan@sibs.ac.cn.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. Tabatarosas@uma.es.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. weiyali@sibs.ac.cn.; University of the Chinese Academy of Sciences, Beijing 100049, China. weiyali@sibs.ac.cn.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. alberto.macho@sibs.ac.cn.; Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China. lozano-duran@sibs.ac.cn.
Plant receptor-like kinases (RLKs) exert an essential function in the transduction of signals from the cell exterior to the cell interior, acting as important regulators of plant development and responses to environmental conditions. A growing body of evidence suggests that RLKs may play relevant roles in plant-virus interactions, although the details and diversity of effects and underlying mechanisms remain elusive. The C4 protein from different geminiviruses has been found to interact with RLKs in the CLAVATA 1 (CLV1) clade. However, whether C4 can interact with RLKs in other subfamilies and, if so, what the biological impact of such interactions might be, is currently unknown. In this work, we explore the interaction landscape of C4 from the geminivirus Tomato yellow leaf curl virus within the Arabidopsis RLK family. Our results show that C4 can interact with RLKs from different subfamilies including, but not restricted to, members of the CLV1 clade. Functional analyses of the interaction of C4 with two well-characterized RLKs, FLAGELLIN SENSING 2 (FLS2) and BRASSINOSTEROID INSENSITIVE 1 (BRI1), indicate that C4 might affect some, but not all, RLK-derived outputs. The results presented here offer novel insight on the interface between RLK signaling and the infection by geminiviruses, and point at C4 as a potential broad manipulator of RLK-mediated signaling.
PMID: 31683645
Plant Physiol Biochem , IF:3.72 , 2019 Oct , V143 : P119-128 doi: 10.1016/j.plaphy.2019.08.024
The putative role of endogenous nitric oxide in brassinosteroid-induced antioxidant defence system in pepper (Capsicum annuum L.) plants under water stress.
Soil Science and Plant Nutrition Department, Harran University, Sanliurfa, Turkey.; University of Agriculture Faisalabad, Pakistan.; Botany and Microbiology Department, College of Science, King Saud University, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia.; Botany and Microbiology Department, College of Science, King Saud University, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia; Department of Botany, S.P. College Srinagar, Jammu and Kashmir, India. Electronic address: parvaizbot@yahoo.com.
Brassinosteroids (BRs) have been rarely tested for their effective roles in mitigation of deleterious effects of water stress (WS) on plants. In addition, the contribution of nitric oxide (NO) in BR-improved plant tolerance to water stress needs to be elucidated. So, a trial was carried out to uncover the contribution of NO in BR-induced tolerance of pepper plants to WS. For well-watered and water-stressed plants, soil water availability was sustained at 80% and 40% of the full water storage capacity, respectively. BR (24-epibrassinolide, EB; 1.0muM) was sprayed to the leaves of both well-watered and water stressed-pepper plants every two days for 10 days prior to the initiation of stress treatment. After starting WS treatment, cPTIO was sprayed to plant leaves twice a week for four weeks. Water stress caused a reduced plant growth and oxidative stress, but the application of EB increased plant growth and reversed the oxidative stress. The EB treatment increased endogenous NO and reinforced antioxidant defence systems, but the cPTIO application reversed the NO levels, downregulated the antioxidant defence systems, and aggravated oxidative damages caused by WS. These results show that EB-induced NO generation and NO-mediated antioxidant defence systems might be crucial mechanisms for EB-improved tolerance of pepper plants to WS. So, both EB and NO jointly are responsible for achieving improved tolerance of pepper plants to water stress.
PMID: 31493672
BMC Genomics , IF:3.594 , 2019 Oct , V20 (1) : P747 doi: 10.1186/s12864-019-6090-6
Genetic mechanisms in the repression of flowering by gibberellins in apple (Malus x domestica Borkh.).
Department of Horticulture and Graduate Program in Plant Breeding, Genetics, and Biotechnology, Michigan State University, 390 Plant and Soil Science Building, 1066 Bogue St., East Lansing, MI, 48824, USA.; Department of Horticulture and Graduate Program in Plant Breeding, Genetics, and Biotechnology, Michigan State University, 390 Plant and Soil Science Building, 1066 Bogue St., East Lansing, MI, 48824, USA. vannocke@msu.edu.
BACKGROUND: Gibberellins (GAs) can have profound effects on growth and development in higher plants. In contrast to their flowering-promotive role in many well-studied plants, GAs can repress flowering in woody perennial plants such as apple (Malus x domestica Borkh.). Although this effect of GA on flowering is intriguing and has commercial importance, the genetic mechanisms linking GA perception with flowering have not been well described. RESULTS: Application of a mixture of bioactive GAs repressed flower formation without significant effect on node number or shoot elongation. Using Illumina-based transcriptional sequence data and a newly available, high-quality apple genome sequence, we generated transcript models for genes expressed in the shoot apex, and estimated their transcriptional response to GA. GA treatment resulted in downregulation of a diversity of genes participating in GA biosynthesis, and strong upregulation of the GA catabolic GA2 OXIDASE genes, consistent with GA feedback and feedforward regulation, respectively. We also observed strong downregulation of numerous genes encoding potential GA transporters and receptors. Additional GA-responsive genes included potential components of cytokinin (CK), abscisic acid (ABA), brassinosteroid, and auxin signaling pathways. Finally, we observed rapid and strong upregulation of both of two copies of a gene previously observed to inhibit flowering in apple, MdTFL1 (TERMINAL FLOWER 1). CONCLUSION: The rapid and robust upregulation of genes associated with GA catabolism in response to exogenous GA, combined with the decreased expression of GA biosynthetic genes, highlights GA feedforward and feedback regulation in the apple shoot apex. The finding that genes with potential roles in GA metabolism, transport and signaling are responsive to GA suggests GA homeostasis may be mediated at multiple levels in these tissues. The observation that TFL1-like genes are induced quickly in response to GA suggests they may be directly targeted by GA-responsive transcription factors, and offers a potential explanation for the flowering-inhibitory effects of GA in apple. These results provide a context for investigating factors that may transduce the GA signal in apple, and contribute to a preliminary genetic framework for the repression of flowering by GAs in a woody perennial plant.
PMID: 31619173
Planta , IF:3.39 , 2019 Oct , V250 (4) : P1371-1377 doi: 10.1007/s00425-019-03233-z
Transcriptional network regulation of the brassinosteroid signaling pathway by the BES1-TPL-HDA19 co-repressor complex.
Department of Biology, Chungbuk National University, Cheongju, 28644, Republic of Korea.; Department of Forest Bio-Resources, National Institute of Forest Science, Suwon, 16631, Republic of Korea.; Department of Biology, Chungbuk National University, Cheongju, 28644, Republic of Korea. hjryu96@chungbuk.ac.kr.
MAIN CONCLUSION: The brassinosteroid-related BES1 and BZR1 transcription factors dynamically modulate downstream gene networks via the TPL-HDA19 co-repressor complex in BR-signaling pathways in Arabidopsis thaliana. Brassinosteroids (BRs) are plant steroid hormones that are essential for diverse growth and developmental processes across the whole life cycle of plants. In Arabidopsis thaliana, the BR-related transcription factors BRI1-EMS-SUPPRESSOR 1 (BES1) and BRASSINAZOLE-RESISTANT 1 (BZR1) regulate a range of global gene expression in response to BR and several external signaling cues; however, the molecular mechanisms by which they mediate the reprogramming of downstream transcription remain unclear. We here report that formation of a protein complex between BES1 and BZR1 and Histone Deacetylase 19 (HDA19) via the conserved ERF-associated amphiphilic repression (EAR) motif proved essential for regulation of BR-signaling-related gene expression. Defects in BR-related functions of BES1 and BZR1 proteins containing a mutated EAR motif were completely rescued by artificial fusion with EAR-repression domain (SRDX), TOPLESS (TPL), or HDA19 proteins. RNA-sequencing analysis of Arabidopsis plants over-expressing bes1-DmEAR or bes1-DmEAR-HDA19 revealed an essential role for HDA19 activity in regulation of BES1/BZR1-mediated BR signaling. In addition to BR-related gene expression, the BES1-HDA19 transcription factor complex was important for abiotic stress-related drought stress tolerance and organ boundary formation. These results suggested that integrating activation of BR-signaling pathways with the formation of the protein complex containing BES1/BZR1 and TPL-HDA19 via the EAR motif was important in fine-tuning BR-related gene networks in plants.
PMID: 31280329
J Plant Physiol , IF:3.013 , 2019 Oct , V241 : P153031 doi: 10.1016/j.jplph.2019.153031
The brassinosteroid receptor kinase, BRI1, plays a role in seed germination and the release of dormancy by cold stratification.
U.S. Department of Agriculture, Agricultural Research Service, Urbana, IL, 61801, USA; Department of Plant Biology, University of Illinois, Urbana-Champaign, IL, 61801, USA. Electronic address: Kim6989@illinois.edu.; Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, 60607, USA.; U.S. Department of Agriculture, Agricultural Research Service, Urbana, IL, 61801, USA; Department of Plant Biology, University of Illinois, Urbana-Champaign, IL, 61801, USA.
Seed dormancy is a critical mechanism that delays germination until environmental conditions are favorable for growth. Plant hormones gibberellin (GA) and abscisic acid (ABA) have long been recognized as key players in regulating dormancy and germination. Recent data have increased interest in brassinosteroid (BR) hormones that promote germination by activating GA downstream genes and inactivating ABA signaling. Exposure of imbibed seeds to low temperature (cold stratification) is widely used to release seed dormancy and to improve germination frequency. However, the mechanism by which cold stratification overcomes the inhibitory role of ABA is not completely understood. In the present study, we show delayed germination of seeds of the BR insensitive mutant, bri1-5, that was largely reversed by treatment with fluridone, an inhibitor of ABA biosynthesis. In addition, the bri1-5 seeds were markedly less sensitive to the cold stratification release of dormancy. These results suggest that BR locates upstream of ABA signaling and downstream of cold stratification signaling in dormancy and germination pathways. Consistent with this notion, BR biosynthetic genes, DWF4 and DET2, were upregulated by cold stratification. The transcripts of the GA biosynthesis gene, GA3ox1, and cold responsive genes, CBF1 and CBF2, increased in response to cold stratification in wild type seeds but not in bri1-5 seeds. Conversely, transgenic seeds overexpressing BRI1 germinated more rapidly than wild type in the absence of cold stratification. Thus, we propose that BR signaling plays a previously unrecognized role in the cold stratification pathway for seed dormancy and germination.
PMID: 31476676
Mol Biol Rep , IF:1.402 , 2019 Oct , V46 (5) : P5295-5308 doi: 10.1007/s11033-019-04986-2
Metabolomic and transcriptomic profiling of three types of litchi pericarps reveals that changes in the hormone balance constitute the molecular basis of the fruit cracking susceptibility of Litchi chinensis cv. Baitangying.
College of Agro-forestry Engineering & Planning, Tongren University, Tongren, 554300, China. wangjugang@catas.cn.; South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Science, Zhanjiang, 524091, China. wangjugang@catas.cn.; Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, Zhanjiang, 524091, China. wangjugang@catas.cn.; Key Laboratory of Tropical Crops Nutrition, Zhanjiang, 524091, Hainan Province, China. wangjugang@catas.cn.; College of Agro-forestry Engineering & Planning, Tongren University, Tongren, 554300, China.; South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Science, Zhanjiang, 524091, China.; Key Laboratory of Tropical Fruit Biology, Ministry of Agriculture, Zhanjiang, 524091, China.; Key Laboratory of Tropical Crops Nutrition, Zhanjiang, 524091, Hainan Province, China.
Many Litchi chinensis cv. Baitangying orchards are suffering from a serious fruit cracking problem, but few studies have improved our understanding of the mechanism or the molecular basis of cracking susceptibility in 'Baitangying'. We conducted metabolome and transcriptome analyses of three types of litchi pericarps. To prevent passive progression after fruit cracking from affecting the results, we mainly focused on 11 metabolites and 101 genes that showed the same regulatory status and overlap in pairwise comparisons of cracking 'Baitangying' versus noncracking 'Baitangying' and noncracking 'Baitangying' versus noncracking 'Feizixiao'. Compared with the cracking-resistant cultivar 'Feizixiao', the 'Baitangying' pericarp has higher abscisic acid contents, and the presence of relevant metabolites and genes suggests increased biosynthesis of ethylene and jasmonic acid and decreased auxin and brassinosteroid biosynthesis. The fruit cracking-susceptible trait in 'Baitangying' might be associated with differences in the balance of these five types of hormones between the pericarp of this cultivar and that of 'Feizixiao'. Additionally, combined analyses showed a correspondence between the metabolite profiles and transcript patterns. qRT-PCR validation indicated the reliability of our high-throughput results. The acquired information might help in further studying the mechanisms that mediate fruit cracking susceptibility in 'Baitangying' and other litchi cultivars.
PMID: 31440876