Wang Jun, Zeng Xuan, Tian Dongsheng, Yang Xiaobei, Wang Lanlan, Yin Zhongchao
Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore.
Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
Mol Plant Pathol. 2018 Mar 30;19(8):2025-35. doi: 10.1111/mpp.12684.
Transcription activator-like effector (TALE)-dependent dominant disease resistance (R) genes in plants, also referred to as executor R genes, are induced on infection by phytopathogenic bacteria of the genus Xanthomonas harbouring the corresponding TALE genes. Unlike the traditional R proteins, the executor R proteins do not determine the resistance specificity and may function broadly in different plant species. The executor R gene Bs4C-R in the resistant genotype PI 235047 of the pepper species Capsicum pubescens (CpBs4C-R) confers disease resistance to Xanthomonas campestris pv. vesicatoria (Xcv) harbouring the TALE genes avrBsP/avrBs4. In this study, the synthetic genes of CpBs4C-R and two other Bs4C-like genes, the susceptible allele in the genotype PI585270 of C. pubescens (CpBs4C-S) and the CaBs4C-R homologue gene in the cultivar 'CM334' of Capsicum annum (CaBs4C), were characterized in tobacco (Nicotiana benthamiana) and rice (Oryza sativa). The Bs4C genes induced cell death in N. benthamiana. The functional Bs4C-eCFP fusion proteins were localized to the endoplasmic reticulum (ER) membrane in the leaf epidermal cells of N. benthamiana. The Xa10 promoter-Bs4C fusion genes in transgenic rice conferred strain-specific disease resistance to Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight in rice, and were specifically induced by the Xa10-incompatible Xoo strain PXO99 (pHM1avrXa10). The results indicate that the Bs4C proteins from pepper species function broadly in rice and the Bs4C protein-mediated cell death from the ER is conserved between dicotyledonous and monocotyledonous plants, which can be utilized to engineer novel and enhanced disease resistance in heterologous plants.
植物中依赖转录激活因子样效应物（TALE）的显性抗病（R）基因，也被称为执行R基因，在携带相应TALE基因的黄单胞菌属植物病原菌感染时被诱导。与传统的R蛋白不同，执行R蛋白不决定抗性特异性，可能在不同植物物种中广泛发挥作用。辣椒属植物毛辣椒（Cp）抗性基因型PI 235047中的执行R基因Bs4C-R（CpBs4C-R）赋予对携带TALE基因avrBsP/avrBs4的野油菜黄单胞菌辣椒斑点病致病变种（Xcv）的抗病性。在本研究中，对CpBs4C-R以及另外两个Bs4C样基因的合成基因进行了表征，这两个基因分别是毛辣椒基因型PI585270中的感病等位基因（CpBs4C-S）和辣椒栽培品种‘CM334’中的CaBs4C-R同源基因（CaBs4C），并在烟草（本氏烟草）和水稻（稻）中进行了研究。Bs4C基因在本氏烟草中诱导细胞死亡。功能性Bs4C-eCFP融合蛋白定位于本氏烟草叶片表皮细胞的内质网（ER）膜上。转基因水稻中的Xa10启动子-Bs4C融合基因赋予对水稻白叶枯病病原菌水稻黄单胞菌水稻致病变种（Xoo）的菌株特异性抗病性，并由Xa10不亲和的Xoo菌株PXO99（pHM1avrXa10）特异性诱导。结果表明，来自辣椒属植物的Bs4C蛋白在水稻中广泛发挥作用，并且内质网介导的Bs4C蛋白细胞死亡在双子叶植物和单子叶植物之间是保守的，这可用于在异源植物中设计新的和增强的抗病性。
