RPW8(resistance to powdery mildew locus 8)是对植物多种病害,尤其白粉病具有抗性的广谱抗病基因位点,通过对橡胶树RPW8基因进行克隆及表达分析,为橡胶树抗白粉病机制解析和分子育种等方面打下基础。以橡胶树‘热研73397’为材料,采用...RPW8(resistance to powdery mildew locus 8)是对植物多种病害,尤其白粉病具有抗性的广谱抗病基因位点,通过对橡胶树RPW8基因进行克隆及表达分析,为橡胶树抗白粉病机制解析和分子育种等方面打下基础。以橡胶树‘热研73397’为材料,采用RT-PCR克隆HbRPW8基因编码区(CDS)序列;对其进行生物信息学分析,并利用qRT-PCR方法,测定7种激素和白粉菌侵染不同时间、不同病害等级处理后RPW8基因表达量。该基因cDNA全长570 bp,编码189个氨基酸,该蛋白的分子量为21.73 kDa,等电点为9.23,脂肪系数为86.30,总平均亲水性指数为-0.404,为亲水性蛋白,共有8个磷酸化位点,无跨膜域和信号肽,定位于细胞核,具有RPW8的保守结构域,α-螺旋和无规则卷曲是HbRPW8蛋白二级结构的主要元件,分别占氨基酸序列的70.90%和22.22%。亲缘关系显示,HbRPW8基因与木薯RPW8基因相似性最高。过氧化氢(H_(2)O_(2))、水杨酸(SA)、乙烯利(ETH)、赤霉素(GA)和脱落酸(ABA)能迅速诱导HbRPW8转录本的表达,并在处理后0.5 h达到最高水平,分别约为对照的14倍、6倍、75倍、2.5倍和4倍;茉莉酸甲酯(MeJA)处理后6h达到最高水平,是对照的10倍左右;生长素处理后HbRPW8转录本显著下调;随着白粉菌侵染时间和病害等级的增加,HbRPW8的表达量均呈现先上升后下降的趋势。研究结果初步表明,HbRPW8可能参与橡胶树的抗病反应机制,为橡胶树抗病育种的研究提供参考。展开更多
Many fungal and oomycete pathogens differentiate a feeding structure named the haustorium to extract nutrition from the plant epidermal cell. The atypical resistance （R） protein RPW8.2 activates salicylic acid （SA...Many fungal and oomycete pathogens differentiate a feeding structure named the haustorium to extract nutrition from the plant epidermal cell. The atypical resistance （R） protein RPW8.2 activates salicylic acid （SA）-dependent, haustorium-targeted defenses against Golovinomyces spp., the causal agents of powdery mildew diseases on multiple plant species. How RPW8.2 activates defense remains uncharacterized. Here, we report that RPWS.2 interacts with the phytochrome-associated protein phosphatase type 2C （PAPP2C） in yeast and in planta as evidenced by co- immunoprecipitation and bimolecular fluorescence complementation assays. Down-regulation of PAPP2C by RNA interfer- ence （RNAi） in Col-0 plants lacking RPWS.2 leads to leaf spontaneous cell death and enhanced disease resistance to powdery mildew via the SA-dependent signaling pathway. Moreover, down-regulation of PAPP2C by RNAi in the RPW8.2 background results in strong HR-like cell death, which correlates with elevated RPWS.2 expression. We further demonstrate that hemagglutinin （HA）-tagged PAPP2C prepared from tobacco leaf cells transiently transformed with HA-PAPP2C possesses phosphatase activity. In addition, silencing a rice gene （Os04g0452000） homologous to PAPP2C also results in spontaneous cell death in rice. Combined, our results suggest that RPW8.2 is functionally connected with PAPP2C and that PAPP2C negatively regulates SA-dependent basal defense against powdery mildew in Arabidopsis.展开更多
文摘RPW8(resistance to powdery mildew locus 8)是对植物多种病害,尤其白粉病具有抗性的广谱抗病基因位点,通过对橡胶树RPW8基因进行克隆及表达分析,为橡胶树抗白粉病机制解析和分子育种等方面打下基础。以橡胶树‘热研73397’为材料,采用RT-PCR克隆HbRPW8基因编码区(CDS)序列;对其进行生物信息学分析,并利用qRT-PCR方法,测定7种激素和白粉菌侵染不同时间、不同病害等级处理后RPW8基因表达量。该基因cDNA全长570 bp,编码189个氨基酸,该蛋白的分子量为21.73 kDa,等电点为9.23,脂肪系数为86.30,总平均亲水性指数为-0.404,为亲水性蛋白,共有8个磷酸化位点,无跨膜域和信号肽,定位于细胞核,具有RPW8的保守结构域,α-螺旋和无规则卷曲是HbRPW8蛋白二级结构的主要元件,分别占氨基酸序列的70.90%和22.22%。亲缘关系显示,HbRPW8基因与木薯RPW8基因相似性最高。过氧化氢(H_(2)O_(2))、水杨酸(SA)、乙烯利(ETH)、赤霉素(GA)和脱落酸(ABA)能迅速诱导HbRPW8转录本的表达,并在处理后0.5 h达到最高水平,分别约为对照的14倍、6倍、75倍、2.5倍和4倍;茉莉酸甲酯(MeJA)处理后6h达到最高水平,是对照的10倍左右;生长素处理后HbRPW8转录本显著下调;随着白粉菌侵染时间和病害等级的增加,HbRPW8的表达量均呈现先上升后下降的趋势。研究结果初步表明,HbRPW8可能参与橡胶树的抗病反应机制,为橡胶树抗病育种的研究提供参考。
基金grants from the National Research Initiative of the USDA Cooperative State Research,Education and Extension Service to S.X.，G.L.W.，a grant from the National Science Foundation (grant number IOS-0842877) to S.X
文摘Many fungal and oomycete pathogens differentiate a feeding structure named the haustorium to extract nutrition from the plant epidermal cell. The atypical resistance （R） protein RPW8.2 activates salicylic acid （SA）-dependent, haustorium-targeted defenses against Golovinomyces spp., the causal agents of powdery mildew diseases on multiple plant species. How RPW8.2 activates defense remains uncharacterized. Here, we report that RPWS.2 interacts with the phytochrome-associated protein phosphatase type 2C （PAPP2C） in yeast and in planta as evidenced by co- immunoprecipitation and bimolecular fluorescence complementation assays. Down-regulation of PAPP2C by RNA interfer- ence （RNAi） in Col-0 plants lacking RPWS.2 leads to leaf spontaneous cell death and enhanced disease resistance to powdery mildew via the SA-dependent signaling pathway. Moreover, down-regulation of PAPP2C by RNAi in the RPW8.2 background results in strong HR-like cell death, which correlates with elevated RPWS.2 expression. We further demonstrate that hemagglutinin （HA）-tagged PAPP2C prepared from tobacco leaf cells transiently transformed with HA-PAPP2C possesses phosphatase activity. In addition, silencing a rice gene （Os04g0452000） homologous to PAPP2C also results in spontaneous cell death in rice. Combined, our results suggest that RPW8.2 is functionally connected with PAPP2C and that PAPP2C negatively regulates SA-dependent basal defense against powdery mildew in Arabidopsis.
