PDF(Pubmed)
Abstract：
As an important member of mitogen-activated protein kinase (MAPK) cascades, MAPKs play an important role in plant defense response against biotic and abiotic stresses; however, the involvement of the majority of the MAPK family members against Ralstonia solanacearum and heat stress (HS) remains poorly understood. In the present study, CaMAPK1 was identified from the genome of pepper and its function against R. solanacearum and HS was analyzed. The transcript accumulations of CaMAPK1 and the activities of its native promoter were both significantly induced by R. solanacearum inoculation, HS, and the application of exogenous hormones, including SA, MeJA, and ABA. Transient expression of CaMAPK1 showed that CaMAPK1 can be targeted throughout the whole cells in Nicotiana benthamiana and triggered chlorosis and hypersensitive response-like cell death in pepper leaves, accompanied by the accumulation of H2O2, and the up-regulations of hormones- and H2O2-associated marker genes. The knock-down of CaMAPK1 enhanced the susceptibility to R. solanacearum partially by down-regulating the expression of hormones- and H2O2-related genes and impairing the thermotolerance of pepper probably by attenuating CaHSFA2 and CaHSP70-1 transcripts. Taken together, our results revealed that CaMAPK1 is regulated by SA, JA, and ABA signaling and coordinates responses to R. solanacearum infection and HS in pepper.
摘要：
作为丝裂原活化蛋白激酶(MAPK)级联反应的重要成员,MAPK在植物对生物和非生物胁迫的防御反应中起着重要作用；然而，大多数MAPK家族成员对青枯菌和热应激（HS）的参与仍然知之甚少。在本研究中,从辣椒基因组中鉴定出CaMAPK1，并分析了其对青枯病和HS的功能。CaMAPK1的转录积累和其天然启动子的活性均显着诱导了青枯菌接种。HS,和外源激素的应用，包括SA,MeJA,和ABA。CaMAPK1的瞬时表达表明，CaMAPK1可以靶向遍及烟草的整个细胞，并引发辣椒叶片的萎黄和超敏反应样细胞死亡。伴随着H2O2的积累，以及激素和H2O2相关标记基因的上调。CaMAPK1的敲低部分通过下调激素和H2O2相关基因的表达而增强了对青枯菌的易感性，并可能通过减弱CaHSFA2和CaHSP70-1转录本而损害了辣椒的耐热性。一起来看,我们的结果表明，CaMAPK1受SA调节，JA,和ABA信号传导，并协调辣椒对青枯菌感染和HS的反应。
