水稻白叶枯病菌avrBs3/PthA家族基因的随机缺失及突变体PXO99Δavr功能的研究  

Studies on random deletion of avrBs3/PthA gene family and the function of mutant PXO99Δavr in Xanthomonas oryzae pv.oryzae

作　　者：段瑞旭[1] 张桂英[1,2] 王春平[1] 宋从凤[1] 王金生[1] 

机构地区：[1]南京农业大学植物保护学院/农业部病虫监测与治理重点开放实验室,江苏南京210095 [2]广西大学农学院,广西南宁530005

出　　处：《南京农业大学学报》2010年第1期59-64,共6页Journal of Nanjing Agricultural University

基　　金：国家973计划项目(2006CB101902);国家863计划项目(2006AA02Z180)

摘　　要：利用来源于水稻白叶枯菌株JXOⅢ的无毒基因avrXa3构建的同源序列突变转化单元,同源重组得到PXO99A菌株的1个缺失突变体PXO99△avr。PXO99A及其突变体基因组DNA以内切酶BamHⅠ完全消化后进行同源检测,发现突变体PXO99△avr中有3条杂交带消失,有2条带信号减弱。进一步以相同探针检测PXO99A的基因文库,限制性酶切分析和Southern杂交归类,共获得13个不同的阳性克隆。众多avrBs3/PthA基因在基因组中单独存在,或2个和2个以上串联排列。经比对,克隆p5所含条带与突变体缺失的5条带大小相同。因此认为随机交换产生的突变体中有5个基因被敲除。将此文库克隆（p5）分别导入PXO99A和突变体PXO99△avr中,苗期接种试验表明：p5互补突变体能使其毒性恢复接近PXO99A的致病表型,推测此克隆正是突变体缺失的基因。同时也表明：缺失的5个串联基因的综合作用主要表现为毒性功能。We used transform unit which covered the gene avrXa3 from JXOⅢ,produced an avirulence gene mutant PXO99△avr by homologous recombination in the strain PXO99~A.PXO99~A and PXO99△avr genomes were digested with BamHⅠcompletely and probed by gene avrXa3.The results demonstrated that PXO99△avr had three bands missing and two bands weakened compared to that of the wild-type strain.We used the same probe to screen PXO99~A genomic library.The results showed that there were 13 different clones in the pathogenic genome.The avrBs3/PthA genes occurred at isolated individual portions or in clusters.A cosmid p5 contained five bands that were identical in size with the bands lost in PXO99△avr.The p5 was transferred into the PXO99~A and the PXO99△avr.Pathogenicity tests in near isogenic lines of rice confirmed that p5 can partly restore the effect of the PXO99△avr, and the predicted p5 may be contain the deleted gene in the mutant.The results also indicate that the p5 plays a virulence role in PXO99~A.

关 键 词：白叶枯病菌 avrBs3/PthA家族基因 水稻近等基因系 致病性 

分 类 号：Q943.2[生物学—植物学]