Department of Plant Pathology and Microbiology, University of California, Riverside, CA, USA.
Phytopathology. 2012 May;102(5):528-38. doi: 10.1094/PHYTO-05-11-0156.
A growth assay in lemon juice and polymerase chain reaction amplifications using newly designed species-specific primers from endopolygalacturonase and β-tubulin genes rapidly differentiated isolates of the morphologically similar fruit sour rot pathogens Galactomyces citriaurantii and G. geotrichum. Isolates of both species were collected from agricultural soils and decaying fruit at locations within and outside California, including worldwide locations, and were used in population genetic studies based on amplified fragment length polymorphic (AFLP) DNA markers. For all four geographically defined subpopulations (three counties of California and locations outside California) among 97 isolates of G. citri-aurantii and for the two subpopulations (origin within or outside California) among 35 isolates of G. geotrichum, the proportion of polymorphic loci and haplotypic diversity was high. In total, 82 unique haplotypes were identified for G. citri-aurantii for the four subpopulations and, of these, 80 haplotypes were unique among subpopulations. For G. geotrichum, 25 unique haplotypes were identified among the two subpopulations and no haplotype was shared. Indices of genetic differences (F(ST)) between subpopulations within each species were all low (e.g., 0.038 for G. geotrichum and 0.085 to 0.226 for G. citriaurantii), indicating a low level of genetic differentiation. Following clone correction, mating type segregation ratios for G. citri-aurantii did not significantly (P > 0.1) deviate from a 1:1 ratio for all four subpopulations or the entire population. Tests of the index of association (I(A)) and parsimony tree-length permutation tests (PTLPT) supported a random mating structure for clone-corrected data for the Kern, Tulare, and Ventura County subpopulations and the null hypothesis of random mating could not be rejected. Additionally, PTLPT also supported random mating for the "outside of California" population. For G. geotrichum, random mating was only tested using I(A) and PTLPT and the null hypothesis of random mating was not rejected (P > 0.05) using clone-corrected data. Further evidence that sexual recombination likely occurs in both species of Galactomyces was the lack of grouping consistency in the unweighted pair-group method with arithmetic mean clustering of AFLP data. A high confidence based on bootstrap values was obtained for only a few of the nodes in each of the two trees. A mixed reproduction system with an out-crossing sexual mating system and a prolific asexual phase is proposed for both species.
在柠檬汁中的生长测定和聚合酶链反应扩增中，使用新设计的内切多聚半乳糖醛酸酶和β-微管蛋白基因的种特异性引物，可快速区分形态相似的果实腐烂病原菌——柑橘酒囊霉和地霉。从加利福尼亚州内外的农业土壤和腐烂水果中收集到这两个种的分离物，并用于基于扩增片段长度多态性（AFLP）DNA 标记的种群遗传研究。在加利福尼亚州的三个县和加利福尼亚州以外的地点的四个地理定义的亚种群（加利福尼亚州的三个县和加利福尼亚州以外的地点）中，对 97 株柑橘酒囊霉和加利福尼亚州内外两个亚种群（起源于加利福尼亚州内外）的 35 株地霉进行了研究，多态性位点和单倍型多样性的比例很高。总共为四个亚种群的柑橘酒囊霉鉴定了 82 个独特的单倍型，其中 80 个单倍型在亚种群之间是独特的。对于地霉，在两个亚种群中鉴定了 25 个独特的单倍型，没有共享的单倍型。每个种内亚种群之间的遗传差异指数（F（ST））均较低（例如，地霉为 0.038，柑橘酒囊霉为 0.085 至 0.226），表明遗传分化程度较低。在进行克隆校正后，对于所有四个亚种群或整个种群，柑橘酒囊霉的交配型分离比均未显著（P > 0.1）偏离 1:1 比。关联指数（I（A））和简约树长置换检验（PTLPT）的检验支持了对 Kern、Tulare 和 Ventura 县亚种群和克隆校正数据的随机交配结构，并且不能拒绝随机交配的零假设。此外，PTLPT 还支持“加利福尼亚州以外”种群的随机交配。对于地霉，仅使用 I（A）和 PTLPT 测试了随机交配，并且使用克隆校正数据不能拒绝随机交配的零假设（P > 0.05）。另外，缺乏 AFLP 数据的未加权对群法算术平均值聚类的分组一致性，这进一步表明两性生殖在两个酒囊霉种中可能发生。仅获得了两棵树中每个树的几个节点的高置信度基于引导值。提出了一种混合繁殖系统，该系统具有异交的有性交配系统和丰富的无性阶段。
