Snow mold fungi cause serious damage to the seedlings of some coniferous species in the boreal region where deep snow covers the seedlings in winter. Racodium therryanum is one of the fungi causing such damage in Japan. Neither sexual nor asexual spores of R. therryanum have been found in the field, and thus, the taxonomy and life cycle of this fungus is unclear. In this study, we developed seven microsatellite markers for population studies such as population structure, recombination and genetic diversity of R. therryanum through de novo genome assembly. Seven microsatellite markers were developed and applied for 133 R. therryanum isolates from Picea glehnii, P. jezoensis and Abies sachalinensis in a nursery and two planted sites in forests (forest sites) situating 10–20 km apart. Little genetic differentiation between the two forest sites suggests that gene flow had occurred between the forest sites. The nursery population was characterized by low genetic diversity compared to the two forest sites. Discriminant analysis of principal components (DAPC) indicated three genetically differentiated clusters of R. therryanum which occurred sympatrically in each site. No dominant clusters were observed in the three host species, and no genetic differentiation was observed among the host species. The observed not significant linkage disequilibrium suggested the genetic recombination of R. therryanum. Microsatellite markers developed in this study can be useful for the further population studies of R. therryanum.

中文翻译：

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新的微卫星标记，用于日本雪枯病的病原体the桐（Racodium theryanum）的种群研究

雪霉菌严重损害了北部地区一些针叶树种的幼苗，而冬季则深雪覆盖了这些树苗。菊苣是在日本引起这种破坏的真菌之一。在野外没有发现有毒的R. therryanum的有性或无性孢子，因此，这种真菌的分类学和生命周期尚不清楚。在这项研究中，我们开发了七个用于群体研究的微卫星标记，例如通过从头基因组组装实现了红斑蛙的种群结构，重组和遗传多样性。7颗微卫星标记开发和应用为133 R. therryanum从株云杉glehnii，P.鱼鳞和Sachalinensis的一个苗圃和两个森林中的人工林（林地）之间的距离为10–20 km。两个森林地点之间几乎没有遗传分化，这表明森林地点之间已经发生了基因流动。与两个森林地点相比，苗圃种群的遗传多样性较低。主成分的判别分析（DAPC）表明，在每个位点上均同胞出现了三个遗传分化的红斑蔷薇。在三个寄主物种中未观察到优势簇，并且在寄主物种之间未观察到遗传分化。观察到的不显着的连锁不平衡表明拟南芥的遗传重组。本研究中开发的微卫星标记物可用于进一步的R. therryanum种群研究。