Garzón Carla D, Geiser David M, Moorman Gary W
Pennsylvania State University, University Park 16802.
Plant Dis. 2005 Jan;89(1):81-89. doi: 10.1094/PD-89-0081.
Accurate identification of Pythium species, the causal agents of Pythium root rot and dampingoff of seedlings, and characterization of populations within the species would greatly assist in selecting and implementing control strategies for these pathogens. Several molecular techniques offer methods for accurate and rapid identification of species, but provide little information about their populations. In this study, amplified fragment length polymorphism (AFLP) fingerprinting was used to characterize plant-pathogenic Pythium species and intraspecific populations. Species-diagnostic AFLP fingerprints for Pythium aphanidermatum, P. irregulare, and P. ultimum, and tentative fingerprints for six other species, were identified. Intraspecific distance analyses of P. aphanidermatum, P. ultimum, and P. irregulare revealed distinct patterns of intraspecific variation among the three species. P. aphanidermatum showed the smallest mean distance among isolates (15%), followed by P. ultimum (37%). P. irregulare had the largest mean distance among isolates (64%), which were divided into two populations with great genetic differentiation (F = 0.2), suggesting the presence of a cryptic species boundary within this species.
准确鉴定引起瓜果腐霉菌根腐病和幼苗猝倒病的瓜果腐霉菌种，并对种内群体进行特征描述，将极大地有助于选择和实施针对这些病原菌的防治策略。几种分子技术提供了准确快速鉴定物种的方法，但关于其群体的信息却很少。在本研究中，扩增片段长度多态性（AFLP）指纹图谱技术被用于对植物病原性瓜果腐霉菌种和种内群体进行特征描述。已鉴定出瓜果腐霉菌、不规则腐霉菌和终极腐霉菌的种诊断AFLP指纹图谱，以及其他六个物种的初步指纹图谱。对瓜果腐霉菌、终极腐霉菌和不规则腐霉菌的种内距离分析揭示了这三个物种种内变异的不同模式。瓜果腐霉菌在分离株间显示出最小的平均距离（15%），其次是终极腐霉菌（37%）。不规则腐霉菌在分离株间具有最大的平均距离（64%），且被分为两个具有很大遗传分化的群体（F = 0.2），这表明该物种内存在一个隐存种界限。
