Phoq介导甘蔗白条黄单胞菌致病力的机制初探  

Preliminary study on the phoq-mediated pathogenicity of Xanthomonas albilineans causing sugarcane leaf scald disease

作　　者：陈文浛 李美霖 吴登 杜金霞 熊丽娅 胡琴 张木清[1,2] CHEN Wenhan;LI Meilin;WU Deng;DU Jinxia;XIONG Liya;HU Qin;ZHANG Muqing(Guangxi Key Laboratory of Sugarcane Biology,Guangxi University,Nanning 530004,China;State Key Laboratory for the Protection and Utilization of Subtropical Agricultural Biological Resources,Nanning 530005,China)

机构地区：[1]广西甘蔗生物学重点实验室,广西大学,南宁530004 [2]亚热带农业生物资源保护与利用国家重点实验室,南宁530005

出　　处：《植物病理学报》2024年第5期985-994,共10页Acta Phytopathologica Sinica

基　　金：广西重大创新基地和人才项目(桂科AD20207020);国家糖料产业技术体系甘蔗抗病品种改良岗位科学家(CARS170109)。

摘　　要：甘蔗白条病是一种由白条黄单胞菌(Xanthomonas albilineans,Xa)引起的细菌性病害,明确Xa的致病机理对甘蔗白条病的防治具有重要意义。在以往的研究中,双组分系统中跨膜的组氨酸蛋白激酶Phoq通过感受外界信号,激活胞内激酶活性,进而调节下游基因的转录水平,是黄单胞菌中重要的信号传递因子。本研究收集了包括Xa在内的能引发植物病害的8种黄单胞菌的Phoq蛋白序列。经过系统发育分析、蛋白质保守基序预测等,发现这8种黄单胞菌中的Phoq蛋白质结构保守,且具有相似的理化性质。进一步采用同源重组双交换的方法对Xa-JG43菌株中的phoq基因进行敲除,发现Xa-phoq敲除突变体的游动性和致病性相比野生型菌株明显减弱,但涌动性和抗胁迫能力不变,而Xa-phoq基因回补菌株的这些性状又恢复至野生型水平,表明Xa-phoq基因是菌体维持运动性和致病性所必需的。研究结果为进一步确定Xa的致病机理奠定了基础。Leaf scald,caused by Xanthomonas albilineans(Xa),is a bacterial disease that seriously affects sugarcane production.Understanding the pathogenicity of this bacterial pathogen is crucial to preventing and controlling sugarcane leaf scald disease.Previous studies have shown that Phoq,a transmembrane histidine protein kinase in the two-component system of Xanthomonas,is a very important transduction factor,sensing extracellular signals,activating intracellular kinase activity,and subsequently regulating downstream gene expression.In this study,we collected Phoq protein sequences from eight pathogenic bacteria in the genus Xanthomonas,including Xa.The results of phylogenetic analysis and motif composition prediction showed that these Phoq proteins have conserved structure and similar physicochemical properties.To further investigate the biological role of phoq in Xa,we produced phoq knockout mutant in Xa-JG43 strain using the homologous recombination method.Compared with the wild-type strain Xa-JG43,the swimming ability and pathogenicity of the Xa-phoq knockout mutant were seriously weakened,but the swarming and stress response ability were not affected;In Xa-phoq complementary strain,the pathogenicity and swimming ability were restored to the level of the wild-type strain.This study provides a theoretical basis for further determination of the pathogenic mechanism of Xa.

关 键 词：甘蔗白条病 白条黄单胞菌 phoq基因 运动能力 致病性 

分 类 号：S435.661[农业科学—农业昆虫与害虫防治]