青枯雷尔氏菌脂肪酸型与致病性的关系

 【目的】分析青枯雷尔氏菌脂肪酸种类变化与致病性指标-弱化指数和回接发病率的相互关系，提出青枯雷尔氏菌脂肪酸型种下分化的分类方法。【方法】青枯雷尔氏菌脂肪酸型分为：脂肪酸Ⅰ型，弱化指数＞0.8，回接发病率0%，属无致病力型;脂肪酸Ⅱ型，弱化指数为0.6～0.8，回接发病率为6.7%～100%，属过渡型，脂肪酸Ⅲ型，弱化指数＜0.6，回接发病率100%，属强致病力型。利用聚类分析、主成分分析、判别分析，分层筛选与脂肪酸型有关的脂肪酸种类.【结果】筛选出十四碳脂肪酸（X1）、十七碳脂肪酸（X9），十八碳脂肪酸（X13）为主要因子，组建数据矩阵，建立脂肪酸型判别模型：Y1=-16.3353 + 0.0012X1 + 0.0056X9 - 0.0016X13，Y2= -3.4928 + 0.0002X1 + 0.0003X9 + 0.0025X13，Y3= -9.1550 - 0.0003X1 + 0.0039X9 + 0.0042X13，对于一个未知脂肪酸型的青枯雷尔氏菌菌株，首先测定脂肪酸图谱，取出X1（十四碳脂肪酸）、X9（十七碳脂肪酸）、X13（十八碳脂肪酸），代入方程，计算Yi，当1≤Yi≤2时，归为脂肪酸型Ⅰ，当2≤Yi≤3时,归为脂肪酸型Ⅱ，当Yi＞3时,归为脂肪酸型Ⅲ，模型的判别准确率达90.00%。【结论】青枯雷尔氏菌脂肪酸型的研究，为其种下分化建模的标准化和计算机自动分析方法的建立，提供可靠的基础。脂肪酸型的模型建立也为其他植物病原菌的致病性研究提供了思路和方法。

Fatty Acid Type of Ralstonia solanacearum Strains and the Relationship with Pathogenicity

【Objective】 The objective of the study was to analyze the relationship between the fatty acid and pathogenicity of Ralstonia solanacearum. 【Method】 The fatty acid types were divided into 3 groups, FAT Ⅰ, Ⅱ, Ⅲ. FAT Ⅰ was characterized with＞0.8 avirulent index, 0% infected mortality, belonging to the non-pathogenicity type, FAT Ⅱ with 0.6-0.8 avirulent index, 6.7%-100% infected mortality, belonging to Transition-virulent type in which the pathogenicity was changeable to cause high and low mortalities to the tomato plantlets, FAT Ⅲ with ＜0.6 avirulent index, 100% stable infected mortality. 【Result】 Using cluster analysis to group the fatty acid, principle component analysis was used to select key factors of fatty acid, discrimination analysis was used to build up the discrimination model, three fatty acid of 14:0(X1), 17:0(X9), 18:0(X13) were put into the model set as follow: Y1=-16.3353 + 0.0012X1 + 0.0056X9 - 0.0016X13，Y2=-3.4928 + 0.0002X1 + 0.0003X9 + 0.0025X13，Y3= -9.1550 - 0.0003X1 + 0.0039X9 + 0.0042X13. 【Conclusion】 The accurate rate for discrimination was up to 90.00%. The model of fatty acid type for R. solanacearum was built to provide experiences for computer-based standardized analysis of the pathogen evolution under species level, furthermore with the new idea for other pathogen differentiation.