葡萄座腔菌候选效应子抑制了Bax诱导的PCD反应并促进烟草疫霉的侵染

Candidate effectors of Botryosphaeria dothidea inhibit Bax induced PCD in Nicotiana benthamiana and promote the infection of Phytophthora nicotianae

轮纹病是苹果生产中发生严重又难以防治的病害。为探究致病机理,本研究选择葡萄座腔菌的3个候选效应子进行研究。农杆菌介导的烟草瞬时表达显示,Bdo_01520、Bdo_11198、Bdo_11545都能够完全抑制Bax诱导的烟草PCD反应。酵母分泌系统测试表明3个候选效应子的信号肽都具有外泌活性。qRT-PCR测定候选效应子在葡萄座腔菌ZY7有伤接种苹果果实后的相对表达量,结果显示3个基因在病菌侵染36～72 h上调表达。在本生烟中瞬时表达Bdo_11198显著促进了烟草疫霉的侵染,并降低了疫霉菌侵染后本生烟中活性氧的积累。结果表明,葡萄座腔菌候选效应子可以通过影响植物的PCD反应和过氧化氢积累促进病原菌的侵染,研究结果为进一步研究葡萄座腔菌的致病机制提供了基础。

Candidate effectors of Botryosphaeria dothidea were transient expressed in the leaves of Nicotiana benthamiana and then challenged with Agrobacteria tumefaciens cells carrying Bax at 24 h after the initial inoculation.Three tested candidate effectors completely inhibited Bax induced programmed cell death(PCD)of N.benthamiana.The secretional signal peptides of these effectors showed secretory activity in yeast system(pSUC2 vector).Expression patterns of the three effectors analyzed by Reverse Transcript-quantitative PCR showed that they were all highly expressed from 36 to 72 h post inoculation in apple fruit.Infiltration of Bdo11198 could significantly increase the infection of Phytophthora nicotianae in N.benthamiana and the reactive oxygen accumulation was less than that of GFP.These results suggested that candidate effectors of B.dothidea might play important roles in the infection on apple.