CLONAL DIVERSITY AND GENETIC DIFFERENTIATION OF PHYTOPHTHORA-INFESTANS POPULATIONS IN NORTHERN AND CENTRAL MEXICO
CLONAL DIVERSITY AND GENETIC DIFFERENTIATION OF PHYTOPHTHORA-INFESTANS POPULATIONS IN NORTHERN AND CENTRAL MEXICO
复制标题
DOI：
10.1094/phyto-82-955
复制
发表时间：
1992-09-01
期刊：
影响因子：
3.2
通讯作者：
FRY, WE
中科院分区：
文献类型：
--
作者：
GOODWIN, SB;SPIELMAN, LJ;FRY, WE
两个致病疫霉种群在北方墨西哥（西北和东北）的遗传变异进行了分析，通过使用交配型，两个等位酶位点，和两个DNA指纹探针，并进行了比较，从墨西哥中部的两个种群。种群的遗传结构差异很大，即使这两种交配类型发生在所有采样地点。墨西哥西北部的遗传多样性很少;在测试的88个分离株中检测到四种基因型，其中只有两种是常见的。在这个群体中的所有A2菌株似乎代表一个单一的克隆，并专门在马铃薯，而A1菌株主要是在番茄。由于A2交配型以前在墨西哥西北部不为人知，这个克隆可能代表了它的范围最近的扩张。与墨西哥西北部的低多样性相反，墨西哥东北部和中部的分离物非常多样化。在墨西哥中部，几乎每个分离株都有一个独特的基因型，这与该地区有性生殖频繁的假设一致。有一个中等程度的遗传分化种群从所有四个地点（内的G（ST）= 0。12个等位酶，0. 14为DNA），表明对基因流动的一些限制。虽然DNA指纹探针提供了更高程度的分辨率，等位酶是令人惊讶的强大的估计许多致病疫霉种群的遗传多样性。在墨西哥西北部和东北部发现了Gpi基因座111的一个先前未报告的等位基因，但在墨西哥中部的样本中没有发现。该等位基因最常出现在五带等位酶表型中，该表型被证明可归因于同一个体中不同染色体上的三个等位基因，因此，为致病疫霉倍性升高提供了第一个遗传证据。
Two Phytophthora infestans populations in northern Mexico (northwestern and northeastern) were analyzed for genetic variation by use of mating type, two allozyme loci, and two DNA fingerprinting probes, and were compared to two populations from central Mexico. The genetic structure of the populations varied widely, even though both mating types occurred in all locations sampled. There was very little genetic diversity in northwestern Mexico; four genotypes were detected among 88 isolates tested, and only two of these were common. All A2 isolates in this population appeared to represent a single clone and were exclusively on potatoes, whereas the A1 isolates were primarily on tomatoes. As the A2 mating type was not known previously in northwestern Mexico, this clone probably represents a recent expansion in its range. In contrast to the low diversity in northwestern Mexico, isolates from northeastern and central Mexico were very diverse. In central Mexico, almost every isolate had a unique genotype, consistent with the hypothesis that sexual reproduction is frequent in this area. There was a moderate degree of genetic differentiation among populations from all four locations (Nei's G(ST) = 0. 12 for allozymes and 0. 14 for DNA), indicating some restriction on gene flow. Although the DNA fingerprinting probes provided a higher degree of resolution, allozymes were surprisingly robust for estimating genetic diversity in many P. infestans populations. A previously unreported allele at the Gpi locus, 111, was found in northwestern and northeastern Mexico, but not in the samples from central Mexico. This allele occurred most often in a five-banded allozyme phenotype that was shown to be attributable to three alleles on different chromosomes in the same individual and, thus, provides the first genetic evidence for elevated ploidy in P. infestans.