Islam Md-Sajedul, Callicott Kenneth A, Mutegi Charity, Bandyopadhyay Ranajit, Cotty Peter J
Agricultural Research Service, United States Department of Agriculture, School of Plant Sciences, University of Arizona, Tucson, AZ, USA.
International Institute of Tropical Agriculture, Nairobi, Kenya.
Fungal Ecol. 2018 Oct;35:20-33. doi: 10.1016/j.funeco.2018.05.012.
has long been considered to be an asexual species. Although a sexual stage was recently reported for this species from studies, the amount of recombination ongoing in natural populations and the genetic distance across which meiosis occurs is largely unknown. In the current study, genetic diversity, reproduction and evolution of natural populations endemic to Kenya were examined. A total of 2744 isolates recovered from 629 maize-field soils across southern Kenya in two consecutive seasons were characterized at 17 SSR loci, revealing high genetic diversity (9-72 alleles/locus and 2140 haplotypes). Clonal reproduction and persistence of clonal lineages predominated, with many identical haplotypes occurring in multiple soil samples and both seasons. Genetic analyses predicted three distinct lineages with linkage disequilibrium and evolutionary relationships among haplotypes within each lineage suggesting mutation-driven evolution followed by clonal reproduction. Low genetic differentiation among adjacent communities reflected frequent short distance dispersal.
长期以来，该物种一直被认为是无性繁殖物种。尽管最近的研究报道了该物种存在有性阶段，但自然种群中正在进行的重组量以及减数分裂发生的遗传距离在很大程度上尚不清楚。在当前的研究中，对肯尼亚特有的自然种群的遗传多样性、繁殖和进化进行了研究。在两个连续季节中，从肯尼亚南部629块玉米田土壤中总共分离出2744个菌株，对其17个SSR位点进行了特征分析，结果显示出高遗传多样性（每个位点9 - 72个等位基因和2140个单倍型）。克隆繁殖和克隆谱系的持续性占主导地位，许多相同的单倍型出现在多个土壤样本以及两个季节中。遗传分析预测出三个不同的谱系，各谱系内单倍型之间存在连锁不平衡和进化关系，表明是由突变驱动进化，随后是克隆繁殖。相邻群落之间较低的遗传分化反映出频繁的短距离扩散。
