Island Cotton <em>Gbve1</em> Gene Encoding A Receptor-Like Protein Confers Resistance to Both Defoliating and Non-Defoliating Isolates of <em>Verticillium dahliae</em>

Verticillium wilt caused by soilborne fungus Verticillium dahliae could significantly reduce cotton yield. Here, we cloned a tomato Ve homologous gene, Gbve1, from an island cotton cultivar that is resistant to Verticillium wilt. We found that the Gbve1 gene was induced by V. dahliae and by phytohormones salicylic acid, jasmonic acid, and ethylene, but not by abscisic acid. The induction of Gbve1 in resistant cotton was quicker and stronger than in Verticillium-susceptible upland cotton following V. dahliae inoculation. Gbve1 promoter-driving GUS activity was found exclusively in the vascular bundles of roots and stems of transgenic Arabidopsis. Virus-induced silencing of endogenous genes in resistant cotton via targeting a fragment of the Gbve1 gene compromised cotton resistance to V. dahliae. Furthermore, we transformed the Gbve1 gene into Arabidopsis and upland cotton through Agrobacterium-mediated transformation. Overexpression of the Gbve1 gene endowed transgenic Arabidopsis and upland cotton with resistance to high aggressive defoliating and non-defoliating isolates of V. dahliae. And HR-mimic cell death was observed in the transgenic Arabidopsis. Our results demonstrate that the Gbve1 gene is responsible for resistance to V. dahliae in island cotton and can be used for breeding cotton varieties that are resistant to Verticillium wilt.由土传真菌大丽轮枝菌（Verticillium dahliae）引发的棉花黄萎病（Verticillium wilt）可显著降低棉花产量。本研究从抗黄萎病的海岛棉品种中克隆得到番茄Ve基因的同源基因Gbve1。研究发现，Gbve1基因可被大丽轮枝菌以及植物激素水杨酸（salicylic acid）、茉莉酸（jasmonic acid）和乙烯（ethylene）诱导表达，但不受脱落酸（abscisic acid）诱导。接种大丽轮枝菌后，抗病海岛棉中Gbve1的诱导表达速度更快、强度更高，显著优于感黄萎病的陆地棉。在转基因拟南芥的根与茎的维管束组织中，仅能检测到以Gbve1启动子驱动的GUS（β-葡萄糖醛酸苷酶）活性。通过靶向Gbve1基因片段对抗病棉花进行病毒诱导的内源基因沉默，会削弱棉花对大丽轮枝菌的抗性。此外，本研究通过农杆菌介导的遗传转化方法，将Gbve1基因分别转化至拟南芥与陆地棉中。过量表达Gbve1基因可使转基因拟南芥和陆地棉获得对高致病力落叶型与非落叶型大丽轮枝菌菌株的抗性。在转基因拟南芥中还观察到了类超敏反应（HR，Hypersensitive response）样细胞死亡现象。本研究结果证实，Gbve1基因是海岛棉抗大丽轮枝菌的核心抗病基因，可用于培育抗黄萎病的棉花新品种。