School of Agriculture and Forestry, Hue University, 102 Phung Hung Street, Hue City, Viet Nam.
Fungal Biol. 2010 Feb-Mar;114(2-3):160-70. doi: 10.1016/j.funbio.2009.11.005.
Phytophthora foot rot of black pepper caused by Phytophthora capsici is a major disease of black pepper (Piper nigrum) throughout Vietnam. To understand the population structure of P. capsici, a large collection of P. capsici isolates from black pepper was studied on the basis of mating type, random amplified microsatellites (RAMS) and repetitive extragenic palindromic (REP) fingerprinting. Two mating types A1 and A2 were detected in four provinces in two climatic regions, with A1:A2 ratios ranging from 1:3 to 1:5. In several instances A1 and A2 mating types were found to co-exist in the same farm or black pepper pole, suggesting the potential for sexual reproduction of P. capsici in the field in Vietnam although its contribution to disease epidemics is uncertain. RAMS and REP DNA fingerprinting analysis of 118 isolates of P. capsici from black pepper showed that the population was genetically more diverse where two mating types were found, although the overall genetic diversity was low with most of the isolates belonging to one clonal group. The implication of these findings is discussed. The low diversity among isolates suggests that the P. capsici population may have originated from a single source. There was no genetic differentiation of isolates from different climatic regions. In addition to the large clonal group, several isolates with unique RAMS/REP phenotypes were also detected. Most of these unique phenotypes belonged to the minority A1 mating type. This may have significant implications for a gradual increase in overall genetic diversity.
胡椒疫霉引起的胡椒疫霉根腐病是越南胡椒（Piper nigrum）的主要病害。为了了解胡椒疫霉的种群结构，对来自胡椒的大量胡椒疫霉分离物进行了研究，依据交配型、随机扩增多态性微卫星（RAMS）和重复外回文（REP）指纹分析。在两个气候区的四个省中检测到了两个交配型 A1 和 A2，A1:A2 比值范围从 1:3 到 1:5。在某些情况下，在同一个农场或胡椒杆上发现 A1 和 A2 交配型共存，表明尽管其对病害流行的贡献不确定，但越南田间胡椒疫霉存在有性繁殖的潜力。对来自胡椒的 118 个胡椒疫霉分离物的 RAMS 和 REP DNA 指纹分析表明，存在两种交配型的地区种群遗传多样性更高，尽管总体遗传多样性较低，大多数分离物属于一个克隆群。讨论了这些发现的意义。分离物之间的低多样性表明，胡椒疫霉种群可能起源于单一来源。来自不同气候区的分离物没有遗传分化。除了大的克隆群外，还检测到了几个具有独特 RAMS/REP 表型的分离物。这些独特表型中的大多数属于少数的 A1 交配型。这可能对整体遗传多样性的逐渐增加有重要意义。
