Dunn A R, Milgroom M G, Meitz J C, McLeod A, Fry W E, McGrath M T, Dillard H R, Smart C D
Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456.
Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853.
Plant Dis. 2010 Dec;94(12):1461-1468. doi: 10.1094/PDIS-03-10-0221.
In 2006, 2007, and 2008, we sampled 257 isolates of Phytophthora capsici from vegetables at 22 sites in four regions of New York, to determine variation in mefenoxam resistance and population genetic structure. Isolates were assayed for mefenoxam resistance and genotyped for mating type and five microsatellite loci. We found mefenoxam-resistant isolates at a high frequency in the Capital District and Long Island, but none were found in western New York or central New York. Both A1 and A2 mating types were found at 12 of the 22 sites, and we detected 126 distinct multilocus genotypes, only nine of which were found at more than one site. Significant differentiation (F) was found in more than 98% of the pairwise comparisons between sites; approximately 24 and 16% of the variation in the population was attributed to differences among regions and sites, respectively. These results indicate that P. capsici in New York is highly diverse, but gene flow among regions and fields is restricted. Therefore, each field needs to be considered an independent population, and efforts to prevent movement of inoculum among fields need to be further emphasized to prevent the spread of this pathogen.
2006年、2007年和2008年，我们从纽约四个地区22个地点的蔬菜上采集了257株辣椒疫霉分离株，以确定甲霜灵抗性的变异情况和群体遗传结构。对分离株进行了甲霜灵抗性检测，并对交配型和五个微卫星位点进行了基因分型。我们在首都区和长岛发现了高频率的甲霜灵抗性分离株，但在纽约西部或纽约中部未发现。在22个地点中的12个地点发现了A1和A2两种交配型，我们检测到126种不同的多位点基因型，其中只有9种在多个地点被发现。在超过98%的地点间成对比较中发现了显著分化（F）；群体中约24%和16%的变异分别归因于地区间和地点间的差异。这些结果表明，纽约的辣椒疫霉具有高度多样性，但地区和田间之间的基因流动受到限制。因此，每个田间都应被视为一个独立的群体，需要进一步强调防止接种体在田间移动的措施，以防止这种病原菌的传播。
