Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of...Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of rice leaf blight disease. The strain PXO99 A has 18 non-TAL(transcription activation-like) effectors; however, their mechanisms of action and host target proteins remain largely unknown. Although the effector XopR from the Xoo strain MAFF311018 was shown to suppress PAMP-triggered immune responses in Arabidopsis, its target has not yet been identified. Here, we show that PXO99 A XopR interacts with BIK1 at the plasma membrane. BIK1 is a receptor-like cytoplasmic kinase(RLCK) belonging to the RLK family of proteins and mediates PAMP-triggered stomatal immunity. In turn, BIK1 phosphorylates XopR. Furthermore, XopR suppresses PAMP-triggered stomatal closure in transgenic Arabidopsis expressing XopR. In addition, XopR is able to associate with RLCKs other than BIK1. These results suggest that XopR likely suppresses plant immunity by targeting BIK1 and other RLCKs.展开更多
Bacterial blight caused by Xanthomonas oryzae pv.oryzae(Xoo) is the most harmful bacterial disease of rice worldwide.Previously,we characterized major disease resistance(MR) gene xa25,which confers race-specific resis...Bacterial blight caused by Xanthomonas oryzae pv.oryzae(Xoo) is the most harmful bacterial disease of rice worldwide.Previously,we characterized major disease resistance(MR) gene xa25,which confers race-specific resistance to Xoo strain PXO339.The xa25 is a recessive allele of the SWEET13 locus,but SWEET13's interaction with PXO339 and how efficiently using this locus for rice breeding still need to be defined.Here we show that the SWEET 13 allele from rice Zhenshan 97 is a susceptibility gene to PXO339.Using this allele's promoter to regulate xa25 resulted in disease,suggesting that the promoter is a key determinant in SWEET13 caused disease in Zhanshan 97 after PXO339 infection.PXO339 transcriptionally induces SWEET13 to cause disease.Partial suppressing SWEET13 expression leads to a high level of resistance to PXO339.Thus,the transcriptionally suppressed SWEET13 functions as xa25 in resistance to PXO339.Hybrid rice is widely grown in many countries.However,recessive MR genes have not been efficiently used for disease resistance breeding in hybrid rice production for both parents of the hybrid have to carry the same recessive gene.However,the suppressed SWEET 13 functions dominantly,which will have advantage to improve the resistance of hybrid rice to xa25-incomptible Xoo.展开更多
基金supported by the National Natural Science Foundation of China(31322009)the National Basic Research Program of China(2015CB910200)the State Key Laboratory of Plant Genomics of China(SKLPG2011B0301,SKLPG2011A0301)
文摘Receptor-like kinases(RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae(Xoo) is the causal agent of rice leaf blight disease. The strain PXO99 A has 18 non-TAL(transcription activation-like) effectors; however, their mechanisms of action and host target proteins remain largely unknown. Although the effector XopR from the Xoo strain MAFF311018 was shown to suppress PAMP-triggered immune responses in Arabidopsis, its target has not yet been identified. Here, we show that PXO99 A XopR interacts with BIK1 at the plasma membrane. BIK1 is a receptor-like cytoplasmic kinase(RLCK) belonging to the RLK family of proteins and mediates PAMP-triggered stomatal immunity. In turn, BIK1 phosphorylates XopR. Furthermore, XopR suppresses PAMP-triggered stomatal closure in transgenic Arabidopsis expressing XopR. In addition, XopR is able to associate with RLCKs other than BIK1. These results suggest that XopR likely suppresses plant immunity by targeting BIK1 and other RLCKs.
基金supported by the National Natural Science Foundation of China(31330062)the National Key Research and Development Program of Chin(2016YFD0100903)
文摘Bacterial blight caused by Xanthomonas oryzae pv.oryzae(Xoo) is the most harmful bacterial disease of rice worldwide.Previously,we characterized major disease resistance(MR) gene xa25,which confers race-specific resistance to Xoo strain PXO339.The xa25 is a recessive allele of the SWEET13 locus,but SWEET13's interaction with PXO339 and how efficiently using this locus for rice breeding still need to be defined.Here we show that the SWEET 13 allele from rice Zhenshan 97 is a susceptibility gene to PXO339.Using this allele's promoter to regulate xa25 resulted in disease,suggesting that the promoter is a key determinant in SWEET13 caused disease in Zhanshan 97 after PXO339 infection.PXO339 transcriptionally induces SWEET13 to cause disease.Partial suppressing SWEET13 expression leads to a high level of resistance to PXO339.Thus,the transcriptionally suppressed SWEET13 functions as xa25 in resistance to PXO339.Hybrid rice is widely grown in many countries.However,recessive MR genes have not been efficiently used for disease resistance breeding in hybrid rice production for both parents of the hybrid have to carry the same recessive gene.However,the suppressed SWEET 13 functions dominantly,which will have advantage to improve the resistance of hybrid rice to xa25-incomptible Xoo.
