Cournoyer B, Sharp J D, Astuto A, Gibbon M J, Taylor J D, Vivian A
Department of Biological Sciences, University of the West of England, Bristol, United Kingdom.
Mol Plant Microbe Interact. 1995 Sep-Oct;8(5):700-8. doi: 10.1094/mpmi-8-0700.
An avirulence gene (designated avrPpiB) from race 3 of Pseudomonas syringae pv. pisi was cloned and sequenced. The gene corresponded to a single open reading frame of 831 nt identified by transposon mutagenesis and subcloning. This ORF encodes a predicted hydrophilic protein of 276 amino acids (MW 31,300). It effects the expression of a resistance mechanism governed by a single genetic locus in pea. Cosegregation of resistance at the R3 locus of pea was observed towards race 3 and a transconjugant carrying the cloned avrPpiB gene according to the predicted 3:1 ratio of resistant:susceptible F2 progeny from a cross between Jade (R3 R3) and Kelvedon Wonder (rr) cultivars. DNA hybridization studies showed avrPpiB to be plasmid-borne in race 3 and suggested the presence of other alleles on one of the endogenous plasmids of races 1 and 7. Disruption of the avrPpiB allele of race 1 and its complementation confirmed its behavior towards pea cultivars expressing the R3 locus. Homologs of avrPpiB were detected in P. syringae pv. phaseolicola, P. syringae pv. maculicola, and P. syringae pv. tomato. The presence of avrPpiB homologs in P. syringae pv. phaseolicola does not match any gene-for-gene pattern of interaction with bean cultivars.
克隆并测序了来自豌豆丁香假单胞菌3号小种的一个无毒基因（命名为avrPpiB）。该基因对应于一个由转座子诱变和亚克隆鉴定的831个核苷酸的单一开放阅读框。这个开放阅读框编码一个预测的由276个氨基酸组成的亲水性蛋白（分子量31,300）。它影响豌豆中由单个基因座控制的抗性机制的表达。根据来自Jade（R3 R3）和Kelvedon Wonder（rr）品种杂交后代中抗性:敏感F2子代预测的3:1比例，观察到豌豆R3基因座对3号小种和携带克隆的avrPpiB基因的转接合子的抗性共分离。DNA杂交研究表明avrPpiB在3号小种中是质粒携带的，并提示在1号和7号小种的一个内源质粒上存在其他等位基因。1号小种的avrPpiB等位基因的破坏及其互补作用证实了它对表达R3基因座的豌豆品种的作用。在菜豆丁香假单胞菌、斑点丁香假单胞菌和番茄丁香假单胞菌中检测到了avrPpiB的同源物。菜豆丁香假单胞菌中avrPpiB同源物的存在与菜豆品种的任何基因对基因互作模式都不匹配。
