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Allelic variation in the Arabidopsis TNL CHS3/CSA1 immune receptor pair reveals two functional cell-death regulatory modes. Cell Host Microbe 2022; 30:1701-1716.e5. [PMID: 36257318 DOI: 10.1016/j.chom.2022.09.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 07/19/2022] [Accepted: 09/20/2022] [Indexed: 01/26/2023]
Abstract
Some plant NLR immune receptors are encoded in head-to-head "sensor-executor" pairs that function together. Alleles of the NLR pair CHS3/CSA1 form three clades. The clade 1 sensor CHS3 contains an integrated domain (ID) with homology to regulatory domains, which is lacking in clades 2 and 3. In this study, we defined two cell-death regulatory modes for CHS3/CSA1 pairs. One is mediated by ID domain on clade 1 CHS3, and the other relies on CHS3/CSA1 pairs from all clades detecting perturbation of an associated pattern-recognition receptor (PRR) co-receptor. Our data support the hypothesis that an ancestral Arabidopsis CHS3/CSA1 pair gained a second recognition specificity and regulatory mechanism through ID acquisition while retaining its original specificity as a "guard" against PRR co-receptor perturbation. This likely comes with a cost, since both ID and non-ID alleles of the pair persist in diverse Arabidopsis populations through balancing selection.
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Ou Y, Tao B, Wu Y, Cai Z, Li H, Li M, He K, Gou X, Li J. Essential roles of SERKs in the ROOT MERISTEM GROWTH FACTOR-mediated signaling pathway. PLANT PHYSIOLOGY 2022; 189:165-177. [PMID: 35134233 PMCID: PMC9070818 DOI: 10.1093/plphys/kiac036] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 01/05/2022] [Indexed: 05/08/2023]
Abstract
ROOT MERISTEM GROWTH FACTORs (RGFs), a group of peptide hormones, play key roles in root apical meristem development. In Arabidopsis (Arabidopsis thaliana), there are 11 members of RGFs, in which at least RGF1, RGF2, and RGF3 are expressed at the root tip and are involved in root stem cell niche maintenance. RGFs are perceived by five functionally redundant receptor-like protein kinases, RGF1 INSENSITIVE 1 (RGI1) to RGI5, to maintain the expression of two downstream APETALA 2 (AP2) transcription factor genes, PLETHORA 1 (PLT1) and PLT2, and to stabilize PLT2. RGI1 to RGI3 were also named RGF RECEPTOR 1 (RGFR1) to RGFR3, respectively. Although previous studies have suggested that BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) and its paralogs, SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASEs (SERKs), may act as coreceptors of RGIs, comprehensive genetic and biochemical analyses have not been well documented. Here, we report that single, double, and triple mutants of SERKs show various degrees of short root phenotypes and insensitivity to exogenously applied RGF1. The interaction between RGIs and BAK1 and their mutual phosphorylation are RGF1 dependent. We also found that RGF1-induced MAPK activation relies on both RGIs and SERKs. We demonstrate that RGIs play redundant roles in regulating root apical meristem development. Therefore, we genetically and biochemically substantiated that SERKs, as coreceptors, play essential roles in the RGF1-mediated signaling pathway.
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Affiliation(s)
| | | | - Yujun Wu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zeping Cai
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Huiqiang Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Meizhen Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Kai He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaoping Gou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jia Li
- Author for correspondence:
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Wang Z, Ma H, Zhang M, Wang Z, Tian Y, Li W, Wang Y. Transcriptional response of Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. leaves grown under full and partial daylight conditions. BMC Genomics 2021; 22:16. [PMID: 33407099 PMCID: PMC7788892 DOI: 10.1186/s12864-020-07266-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/23/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Asarum heterotropides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. is an important medicinal and industrial plant, which is used in the treatment of various diseases. The main bioactive ingredient is the volatile oil having more than 82 identified components of which methyleugenol, safrole, myristicin, and toluene account for about 70% of the total volume. As a sciophyte plant, the amount of light it absorbs through leaves is an important factor for growth and metabolism. RESULTS We grew Asarum plants under full, 50, 28, and 12% sunlight conditions to investigate the effect of different light irradiances on the four major volatile oil components. We employed de novo transcriptome sequencing to understand the transcriptional behavior of Asarum leaves regarding the biosynthetic pathways of the four volatile oil components, photosynthesis and biomass accumulation, and hormone signaling. Our results demonstrated that the increasing light conditions promoted higher percent of the four components. Under full sunlight conditions, cinnamyl alcohol dehydrogenase and cytochrome p450719As were upregulated and led the increased methyleugenol, safrole, and myristicin. The transcriptomic data also showed that Asarum leaves, under full sunlight conditions, adjust their photosynthesis-antenna proteins as a photoprotective response with the help of carotenoids. Plant hormone-signaling related genes were also differentially expressed between full sunlight and low light conditions. CONCLUSIONS High light induces accumulation of major bioactive ingredients A. heterotropides volatile oil and this is ascribed to upregulation of key genes such as cinnamyl alcohol dehydrogenase and cytochrome p450719As. The transcriptome data presented here lays the foundation of further understanding of light responses in sciophytes and provides guidance for increasing bioactive molecules in Asarum.
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Affiliation(s)
- Zhiqing Wang
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China.
| | - Haiqin Ma
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agriculture Sciences, Changchun, 130112, Jilin, China
| | - Min Zhang
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Ziqing Wang
- Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agriculture Sciences, Changchun, 130112, Jilin, China
| | - Yixin Tian
- Laboratory of Cultivation and Breeding of Medicinal Plants, National Administration of Traditional Chinese Medicine, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Wei Li
- State & Local Joint Engineering Research Center of Ginseng Breeding and Application, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
| | - Yingping Wang
- State & Local Joint Engineering Research Center of Ginseng Breeding and Application, College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, Jilin, China
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Abstract
Plants utilize a two-tiered immune system consisting of pattern recognition receptor (PRR)-triggered immunity (PTI) and effector-triggered immunity (ETI) to defend themselves against pathogenic microbes. The receptor protein kinase BAK1 plays a central role in multiple PTI signaling pathways in Arabidopsis However, double mutants made by BAK1 and its closest paralog BKK1 exhibit autoimmune phenotypes, including cell death resembling a typical nucleotide-binding leucine-rich repeat protein (NLR)-mediated ETI response. The molecular mechanisms of the cell death caused by the depletion of BAK1 and BKK1 are poorly understood. Here, we show that the cell-death phenotype of bak1 bkk1 is suppressed when a group of NLRs, ADR1s, are mutated, indicating the cell-death of bak1 bkk1 is the consequence of NLR activation. Furthermore, introduction of a Pseudomonas syringae effector HopB1, which proteolytically cleaves activated BAK1 and its paralogs via either gene transformation or bacterium-delivery, results in a cell-death phenotype in an ADR1s-dependent manner. Our study thus pinpoints that BAK1 and its paralogs are likely guarded by NLRs.
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Ye Z, Liu J, Jin Y, Cui H, An X, Fu X, Yu X. Physiological and proteomic changes in Zizania latifolia under chilling stress. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gao Y, Wu Y, Du J, Zhan Y, Sun D, Zhao J, Zhang S, Li J, He K. Both Light-Induced SA Accumulation and ETI Mediators Contribute to the Cell Death Regulated by BAK1 and BKK1. FRONTIERS IN PLANT SCIENCE 2017; 8:622. [PMID: 28487714 PMCID: PMC5403931 DOI: 10.3389/fpls.2017.00622] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/06/2017] [Indexed: 05/10/2023]
Abstract
Receptor-like kinases BAK1 and BKK1 modulate multiple cellular processes including brassinosteroid signaling and PRR-mediated PTI in Arabidopsis. Our previous reports also demonstrated that bak1 bkk1 double mutants exhibit a spontaneous cell death phenotype under normal growth condition. With an unknown mechanism, the cell death in bak1 bkk1 is significantly suppressed when grown in dark but can be quickly induced by light. Furthermore, little is known about intrinsic components involved in BAK1 and BKK1-regulated cell death pathway. In this study, we analyzed how light functions as an initiator of cell death and identified ETI components to act as mediators of cell death signaling in bak1 bkk1. Cell death suppressed in bak1 bkk1 by growing in dark condition recurred upon exogenously treated SA. SA biosynthesis-related genes SID2 and EDS5, which encode chloroplast-localized proteins, were highly expressed in bak1-4 bkk1-1. When crossed to bak1-3 bkk1-1, sid2 or eds5 was capable of efficiently suppressing the cell death. It suggested that overly produced SA is crucial for inducing cell death in bak1 bkk1 grown in light. Notably, bak1-3 or bkk1-1 single mutant was shown to be more susceptible but bak1-3 bkk1-1 double mutant exhibited enhanced resistance to bacterial pathogen, suggesting immune signaling other than PTI is activated in bak1 bkk1. Moreover, genetic analyses showed that mutation in EDS1 or PAD4, key ETI mediator, significantly suppressed the cell death in bak1-3 bkk1-1. In this study, we revealed that light-triggered SA accumulation plays major role in inducing the cell death in bak1 bkk1, mediated by ETI components.
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Yu TY, Shi DQ, Jia PF, Tang J, Li HJ, Liu J, Yang WC. The Arabidopsis Receptor Kinase ZAR1 Is Required for Zygote Asymmetric Division and Its Daughter Cell Fate. PLoS Genet 2016; 12:e1005933. [PMID: 27014878 PMCID: PMC4807781 DOI: 10.1371/journal.pgen.1005933] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 02/23/2016] [Indexed: 11/19/2022] Open
Abstract
Asymmetric division of zygote is critical for pattern formation during early embryogenesis in plants and animals. It requires integration of the intrinsic and extrinsic cues prior to and/or after fertilization. How these cues are translated into developmental signals is poorly understood. Here through genetic screen for mutations affecting early embryogenesis, we identified an Arabidopsis mutant, zygotic arrest 1 (zar1), in which zygote asymmetric division and the cell fate of its daughter cells were impaired. ZAR1 encodes a member of the RLK/Pelle kinase family. We demonstrated that ZAR1 physically interacts with Calmodulin and the heterotrimeric G protein Gβ, and ZAR1 kinase is activated by their binding as well. ZAR1 is specifically expressed micropylarly in the embryo sac at eight-nucleate stage and then in central cell, egg cell and synergids in the mature embryo sac. After fertilization, ZAR1 is accumulated in zygote and endosperm. The disruption of ZAR1 and AGB1 results in short basal cell and an apical cell with basal cell fate. These data suggest that ZAR1 functions as a membrane integrator for extrinsic cues, Ca2+ signal and G protein signaling to regulate the division of zygote and the cell fate of its daughter cells in Arabidopsis.
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Affiliation(s)
- Tian-Ying Yu
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Dong-Qiao Shi
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Peng-Fei Jia
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jun Tang
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Hong-Ju Li
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jie Liu
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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Gruszka D. The brassinosteroid signaling pathway-new key players and interconnections with other signaling networks crucial for plant development and stress tolerance. Int J Mol Sci 2013; 14:8740-74. [PMID: 23615468 PMCID: PMC3676754 DOI: 10.3390/ijms14058740] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 12/15/2022] Open
Abstract
Brassinosteroids (BRs) are a class of steroid hormones regulating a wide range of physiological processes during the plant life cycle from seed development to the modulation of flowering and senescence. The last decades, and recent years in particular, have witnessed a significant advance in the elucidation of the molecular mechanisms of BR signaling from perception by the transmembrane receptor complex to the regulation of transcription factors influencing expression of the target genes. Application of the new approaches shed light on the molecular functions of the key players regulating the BR signaling cascade and allowed identification of new factors. Recent studies clearly indicated that some of the components of BR signaling pathway act as multifunctional proteins involved in other signaling networks regulating diverse physiological processes, such as photomorphogenesis, cell death control, stomatal development, flowering, plant immunity to pathogens and metabolic responses to stress conditions, including salinity. Regulation of some of these processes is mediated through a crosstalk between BR signalosome and the signaling cascades of other hormones, including auxin, abscisic acid, ethylene and salicylic acid. Unravelling the complicated mechanisms of BR signaling and its interconnections with other molecular networks may be of great importance for future practical applications in agriculture.
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Affiliation(s)
- Damian Gruszka
- Department of Genetics, Faculty of Biology and Environment Protection, University of Silesia, Jagiellonska 28, Katowice 40-032, Poland.
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9
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Du J, Yin H, Zhang S, Wei Z, Zhao B, Zhang J, Gou X, Lin H, Li J. Somatic embryogenesis receptor kinases control root development mainly via brassinosteroid-independent actions in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:388-399. [PMID: 22525267 DOI: 10.1111/j.1744-7909.2012.01124.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Brassinosteroids (BRs), a group of plant steroidal hormones, play critical roles in many aspects of plant growth and development. Previous studies showed that BRI1-mediated BR signaling regulates cell division and differentiation during Arabidopsis root development via interplaying with auxin and other phytohormones. Arabidopsis somatic embryogenesis receptor-like kinases (SERKs), as co-receptors of BRI1, were found to play a fundamental role in an early activation step of BR signaling pathway. Here we report a novel function of SERKs in regulating Arabidopsis root development. Genetic analyses indicated that SERKs control root growth mainly via a BR-independent pathway. Although BR signaling pathway is completely disrupted in the serk1 bak1 bkk1 triple mutant, the root growth of the triple mutant is much severely damaged than the BR deficiency or signaling null mutants. More detailed analyses indicated that the triple mutant exhibited drastically reduced expression of a number of genes critical to polar auxin transport, cell cycle, endodermis development and root meristem differentiation, which were not observed in null BR biosynthesis mutant cpd and null BR signaling mutant bri1-701.
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Affiliation(s)
- Junbo Du
- School of Life Sciences, Sichuan University, Sichuan 610064, China
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10
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Genome-wide analysis of a TaLEA-introduced transgenic Populus simonii × Populus nigra dwarf mutant. Int J Mol Sci 2012; 13:2744-2762. [PMID: 22489122 PMCID: PMC3317382 DOI: 10.3390/ijms13032744] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 11/09/2011] [Accepted: 02/03/2012] [Indexed: 11/16/2022] Open
Abstract
A dwarf mutant (dwf1) was obtained among 15 transgenic lines, when TaLEA (Tamarix androssowii late embryogenesis abundant gene) was introduced into Populus simonii × Populus nigra by Agrobacterium tumefaciens-mediated transformation. Under the same growth conditions, dwf1 height was significantly reduced compared with the wild type and the other transgenic lines. Because only one transgenic line (dwf1) displayed the dwarf phenotype, we considered that T-DNA insertion sites may play a role in the mutant formation. The mechanisms underlying this effect were investigated using TAIL-PCR (thermal asymmetric interlaced PCR) and microarrays methods. According to the TAIL-PCR results, two flanking sequences located on chromosome IV and VIII respectively, were cloned. The results indicated the integration of two independent T-DNA copies. We searched for the potential genes near to the T-DNA insertions. The nearest gene was a putative poplar AP2 transcription factor (GI: 224073210). Expression analysis showed that AP2 was up-regulated in dwf1 compared with the wild type and the other transgenic lines. According to the microarrays results, a total of 537 genes involved in hydrolase, kinase and transcription factor activities, as well as protein and nucleotide binding, showed significant alterations in gene expression. These genes were expressed in more than 60 metabolic pathways, including starch, sucrose, galactose and glycerolipid metabolism and phenylpropanoids and flavonoid biosyntheses. Our transcriptome and T-DNA insertion sites analyses might provide some useful insights into the dwarf mutant formation.
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Gou X, Yin H, He K, Du J, Yi J, Xu S, Lin H, Clouse SD, Li J. Genetic evidence for an indispensable role of somatic embryogenesis receptor kinases in brassinosteroid signaling. PLoS Genet 2012; 8:e1002452. [PMID: 22253607 PMCID: PMC3257278 DOI: 10.1371/journal.pgen.1002452] [Citation(s) in RCA: 197] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 11/18/2011] [Indexed: 11/24/2022] Open
Abstract
The Arabidopsis thaliana Somatic Embryogenesis Receptor Kinases (SERKs) consist of five members, SERK1 to SERK5, of the leucine-rich repeat receptor-like kinase subfamily II (LRR-RLK II). SERK3 was named BRI1-Associated Receptor Kinase 1 (BAK1) due to its direct interaction with the brassinosteroid (BR) receptor BRI1 in vivo, while SERK4 has also been designated as BAK1-Like 1 (BKK1) for its functionally redundant role with BAK1. Here we provide genetic and biochemical evidence to demonstrate that SERKs are absolutely required for early steps in BR signaling. Overexpression of four of the five SERKs—SERK1, SERK2, SERK3/BAK1, and SERK4/BKK1—suppressed the phenotypes of an intermediate BRI1 mutant, bri1-5. Overexpression of the kinase-dead versions of these four genes in the bri1-5 background, on the other hand, resulted in typical dominant negative phenotypes, resembling those of null BRI1 mutants. We isolated and generated single, double, triple, and quadruple mutants and analyzed their phenotypes in detail. While the quadruple mutant is embryo-lethal, the serk1 bak1 bkk1 triple null mutant exhibits an extreme de-etiolated phenotype similar to a null bri1 mutant. While overexpression of BRI1 can drastically increase hypocotyl growth of wild-type plants, overexpression of BRI1 does not alter hypocotyl growth of the serk1 bak1 bkk1 triple mutant. Biochemical analysis indicated that the phosphorylation level of BRI1 in serk1 bak1 bkk1 is incapable of sensing exogenously applied BR. As a result, the unphosphorylated level of BES1 has lost its sensitivity to the BR treatment in the triple mutant, indicating that the BR signaling pathway has been completely abolished in the triple mutant. These data clearly demonstrate that SERKs are essential to the early events of BR signaling. Brassinosteroids (BRs) are a group of plant hormones critical for plant growth and development. BRs are perceived by a cell-surface receptor complex including two distinctive receptor kinases, BRI1 and BAK1. Whereas BRI1 is a true BR-binding receptor, BAK1 does not appear to have BR-binding activity. Therefore, BAK1 is likely a co-receptor in BR signal transduction. The genetic significance of BAK1 was not clearly demonstrated in previous studies largely due to functional redundancy of BAK1 and its closely related homologues. It was not clear whether BAK1 plays an essential role or only an enhancing role in BR signaling. In this study, we identified all possible BAK1 redundant genes in the Arabidopsis thaliana genome and generated single, double, triple, and quadruple mutants. Detailed analysis indicated that, without BAK1 and its functionally redundant proteins, BR signaling is completely disrupted, largely because BRI1 has lost its ability to activate downstream components. These studies provide the first piece of loss-of-functional genetic evidence that BAK1 is indispensable to the early events of the BR signaling pathway.
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Affiliation(s)
- Xiaoping Gou
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Hongju Yin
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Kai He
- Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Junbo Du
- School of Life Sciences, Lanzhou University, Lanzhou, China
- School of Life Sciences, Sichuan University, Chengdu, China
| | - Jing Yi
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Shengbao Xu
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Honghui Lin
- School of Life Sciences, Sichuan University, Chengdu, China
| | - Steven D. Clouse
- Department of Horticultural Science, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jia Li
- School of Life Sciences, Lanzhou University, Lanzhou, China
- Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States of America
- * E-mail:
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Tena G, Boudsocq M, Sheen J. Protein kinase signaling networks in plant innate immunity. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:519-29. [PMID: 21704551 PMCID: PMC3191242 DOI: 10.1016/j.pbi.2011.05.006] [Citation(s) in RCA: 281] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 05/28/2011] [Accepted: 05/30/2011] [Indexed: 05/18/2023]
Abstract
In plants and animals, innate immunity is triggered through pattern recognition receptors (PRRs) in response to microbe-associated molecular patterns (MAMPs) to provide the first line of inducible defense. Plant receptor protein kinases (RPKs) represent the main plasma membrane PRRs perceiving diverse MAMPs. RPKs also recognize secondary danger-inducible plant peptides and cell-wall signals. Both types of RPKs trigger rapid and convergent downstream signaling networks controlled by calcium-activated PKs and mitogen-activated PK (MAPK) cascades. These PK signaling networks serve specific and overlapping roles in controlling the activities and synthesis of a plethora of transcription factors (TFs), enzymes, hormones, peptides and antimicrobial chemicals, contributing to resistance against bacteria, oomycetes and fungi.
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Affiliation(s)
- Guillaume Tena
- Department of Genetics, Harvard Medical School, Massachusetts General Hospital, MA 02114, USA
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Kawahigashi H, Kasuga S, Ando T, Kanamori H, Wu J, Yonemaru JI, Sazuka T, Matsumoto T. Positional cloning of ds1, the target leaf spot resistance gene against Bipolaris sorghicola in sorghum. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 123:131-42. [PMID: 21442410 DOI: 10.1007/s00122-011-1572-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 03/11/2011] [Indexed: 05/09/2023]
Abstract
Target leaf spot is one of the major sorghum diseases in southern Japan and caused by a necrotrophic fungus, Bipolaris sorghicola. Sorghum resistance to target leaf spot is controlled by a single recessive gene (ds1). A high-density genetic map of the ds1 locus was constructed with simple sequence repeat markers using progeny from crosses between a sensitive variety, bmr-6, and a resistant one, SIL-05, which allowed the ds1 gene to be genetically located within a 26-kb region on the short arm of sorghum chromosome 5. The sorghum genome annotation database for BTx623, for which the whole genome sequence was recently published, indicated a candidate gene from the Leucine-Rich Repeat Receptor Kinase family in this region. The candidate protein kinase gene was expressed in susceptible plants but was not expressed or was severely reduced in resistant plants. The expression patterns of ds1 gene and the phenotype of target leaf spot resistance were clearly correlated. Genomic sequences of this region in parental varieties showed a deletion in the promoter region of SIL-05 that could cause reduction of gene expression. We also found two ds1 alleles for resistant phenotypes with a stop codon in the coding region. The results shown here strongly suggest that the loss of function or suppression of the ds1 protein kinase gene leads to resistance to target leaf spot in sorghum.
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Ye H, Li L, Yin Y. Recent advances in the regulation of brassinosteroid signaling and biosynthesis pathways. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2011; 53:455-68. [PMID: 21554539 DOI: 10.1111/j.1744-7909.2011.01046.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Brassinosteroids (BRs) play important roles in plant growth, development and responses to environmental cues. BRs signal through plasma membrane receptor BRI1 and co-receptor BAK1, and several positive (BSK1, BSU1, PP2A) and negative (BKI1, BIN2 and 14-3-3) regulators to control the activities of BES1 and BZR1 family transcription factors, which regulate the expression of hundreds to thousands of genes for various BR responses. Recent studies identified novel signaling components in the BR pathways and started to establish the detailed mechanisms on the regulation of BR signaling. In addition, the molecular mechanism and transcriptional network through which BES1 and BZR1 control gene expression and various BR responses are beginning to be revealed. BES1 recruits histone demethylases ELF6 and REF6 as well as a transcription elongation factor IWS1 to regulate target gene expression. Identification of BES1 and BZR1 target genes established a transcriptional network for BR response and crosstalk with other signaling pathways. Recent studies also revealed regulatory mechanisms of BRs in many developmental processes and regulation of BR biosynthesis. Here we provide an overview and discuss some of the most recent progress in the regulation of BR signaling and biosynthesis pathways.
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Affiliation(s)
- Huaxun Ye
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, USA
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Roux M, Schwessinger B, Albrecht C, Chinchilla D, Jones A, Holton N, Malinovsky FG, Tör M, de Vries S, Zipfel C. The Arabidopsis leucine-rich repeat receptor-like kinases BAK1/SERK3 and BKK1/SERK4 are required for innate immunity to hemibiotrophic and biotrophic pathogens. THE PLANT CELL 2011; 23:2440-55. [PMID: 21693696 PMCID: PMC3160018 DOI: 10.1105/tpc.111.084301] [Citation(s) in RCA: 483] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 05/24/2011] [Accepted: 06/08/2011] [Indexed: 05/18/2023]
Abstract
Recognition of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern recognition receptors (PRRs) constitutes an important layer of innate immunity in plants. The leucine-rich repeat (LRR) receptor kinases EF-TU RECEPTOR (EFR) and FLAGELLIN SENSING2 (FLS2) are the PRRs for the peptide PAMPs elf18 and flg22, which are derived from bacterial EF-Tu and flagellin, respectively. Using coimmunoprecipitation and mass spectrometry analyses, we demonstrated that EFR and FLS2 undergo ligand-induced heteromerization in planta with several LRR receptor-like kinases that belong to the SOMATIC-EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) family, including BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1/SERK3 (BAK1/SERK3) and BAK1-LIKE1/SERK4 (BKK1/SERK4). Using a novel bak1 allele that does not exhibit pleiotropic defects in brassinosteroid and cell death responses, we determined that BAK1 and BKK1 cooperate genetically to achieve full signaling capability in response to elf18 and flg22 and to the damage-associated molecular pattern AtPep1. Furthermore, we demonstrated that BAK1 and BKK1 contribute to disease resistance against the hemibiotrophic bacterium Pseudomonas syringae and the obligate biotrophic oomycete Hyaloperonospora arabidopsidis. Our work reveals that the establishment of PAMP-triggered immunity (PTI) relies on the rapid ligand-induced recruitment of multiple SERKs within PRR complexes and provides insight into the early PTI signaling events underlying this important layer of plant innate immunity.
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Affiliation(s)
- Milena Roux
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | | | - Catherine Albrecht
- Department of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | - Delphine Chinchilla
- Zurich-Basel Plant Science Center, Botanical Institute, University of Basel, 4056 Basel, Switzerland
| | - Alexandra Jones
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Nick Holton
- School of Life Sciences, University of Warwick, Wellesbourne, Warwick CV35 9EF, United Kingdom
| | | | - Mahmut Tör
- School of Life Sciences, University of Warwick, Wellesbourne, Warwick CV35 9EF, United Kingdom
| | - Sacco de Vries
- Department of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
- Address correspondence to
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Phosphorylation-dependent differential regulation of plant growth, cell death, and innate immunity by the regulatory receptor-like kinase BAK1. PLoS Genet 2011; 7:e1002046. [PMID: 21593986 PMCID: PMC3085482 DOI: 10.1371/journal.pgen.1002046] [Citation(s) in RCA: 356] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 02/21/2011] [Indexed: 01/02/2023] Open
Abstract
Plants rely heavily on receptor-like kinases (RLKs) for perception and
integration of external and internal stimuli. The Arabidopsis regulatory
leucine-rich repeat RLK (LRR-RLK) BAK1 is involved in steroid hormone responses,
innate immunity, and cell death control. Here, we describe the differential
regulation of three different BAK1-dependent signaling pathways by a novel
allele of BAK1, bak1-5. Innate immune signaling mediated by the
BAK1-dependent RKs FLS2 and EFR is severely compromised in
bak1-5 mutant plants. However, bak1-5
mutants are not impaired in BR signaling or cell death control. We also show
that, in contrast to the RD kinase BRI1, the non-RD kinases FLS2 and EFR have
very low kinase activity, and we show that neither was able to
trans-phosphorylate BAK1 in vitro. Furthermore, kinase activity
for all partners is completely dispensable for the ligand-induced
heteromerization of FLS2 or EFR with BAK1 in planta, revealing
another pathway specific mechanistic difference. The specific suppression of
FLS2- and EFR-dependent signaling in bak1-5 is not due to a
differential interaction of BAK1-5 with the respective ligand-binding RK but
requires BAK1-5 kinase activity. Overall our results demonstrate a
phosphorylation-dependent differential control of plant growth, innate immunity,
and cell death by the regulatory RLK BAK1, which may reveal key differences in
the molecular mechanisms underlying the regulation of ligand-binding RD and
non-RD RKs. Plants need to adapt to their ever-changing environment for survival.
Transmembrane receptor kinases are essential to translate extracellular stimuli
into intracellular responses. A key question is how plants maintain signaling
specificity in response to multiple stresses and endogenous hormones. Growth
responses induced by steroid hormones and innate immunity triggered by
recognition of conserved microbial molecules depend on the common regulatory
receptor-like kinase BAK1, which is also involved in cell death control. It is
still unclear if BAK1 provides signaling specificity or if it is a mere
signaling enhancer. Here, we describe the novel protein variant BAK1-5 that
specifically blocks innate immune responses without affecting steroid responses
or cell death. This unambiguously demonstrates that the role of BAK1 in plant
signaling can be mechanistically separated. Importantly, the impairment of
immune signaling is not caused by a loss of interaction of BAK1-5 with immune
receptors but is due to an altered kinase activity. Thus, BAK1-dependent
signaling pathways are under a differential phosphorylation-dependent
regulation. The examination of this novel mutant version of BAK1 will enable
detailed studies into the mechanistic role of BAK1 in plant innate immunity, but
also more generally will provide invaluable insights into transmembrane receptor
signaling specificity in plants.
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Thamatrakoln K, Korenovska O, Niheu AK, Bidle KD. Whole-genome expression analysis reveals a role for death-related genes in stress acclimation of the diatom Thalassiosira pseudonana. Environ Microbiol 2011; 14:67-81. [DOI: 10.1111/j.1462-2920.2011.02468.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Kim TW, Wang ZY. Brassinosteroid signal transduction from receptor kinases to transcription factors. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:681-704. [PMID: 20192752 DOI: 10.1146/annurev.arplant.043008.092057] [Citation(s) in RCA: 396] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Brassinosteroids (BRs) are growth-promoting steroid hormones in plants. Genetic studies in Arabidopsis illustrated the essential roles of BRs in a wide range of developmental processes and helped identify many genes involved in BR biosynthesis and signal transduction. Recently, proteomic studies identified missing links. Together, these approaches established the BR signal transduction cascade, which includes BR perception by the BRI1 receptor kinase at the cell surface, activation of BRI1/BAK1 kinase complex by transphosphorylation, subsequent phosphorylation of the BSK kinases, activation of the BSU1 phosphatase, dephosphorylation and inactivation of the BIN2 kinase, and accumulation of unphosphorylated BZR transcription factors in the nucleus. Mass spectrometric analyses are providing detailed information on the phosphorylation events involved in each step of signal relay. Thus, the BR signaling pathway provides a paradigm for understanding receptor kinase-mediated signal transduction as well as tools for the genetic improvement of the productivity of crop plants.
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Affiliation(s)
- Tae-Wuk Kim
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA
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Chinchilla D, Shan L, He P, de Vries S, Kemmerling B. One for all: the receptor-associated kinase BAK1. TRENDS IN PLANT SCIENCE 2009; 14:535-41. [PMID: 19748302 PMCID: PMC4391746 DOI: 10.1016/j.tplants.2009.08.002] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 08/03/2009] [Accepted: 08/04/2009] [Indexed: 05/18/2023]
Abstract
The plant receptor kinase BAK1/SERK3 has been identified as a partner of ligand-binding leucine-rich repeat receptor kinases, in particular the brassinosteroid receptor BRI1 and the immune receptor FLS2. BAK1 positively regulates BRI1 receptor function via physical interaction and transphosphorylation. Since its first description in 2001, several independent groups have discovered BAK1/SERK3 as a component of diverse processes, including brassinosteroid signaling, light responses, cell death, and plant innate immunity. Here, we summarize current knowledge of the functional repertoire of BAK1 and discuss how its multiple functions could be integrated, how receptor complexes are potentially formed and how specificity might be determined.
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Affiliation(s)
- Delphine Chinchilla
- Zürich-Basel Plant Science Center, Botanical Institute, University of Basel, 4056 Basel, Switzerland
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