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Pseudogymnoascus destructans is the causative agent of an emerging infectious disease that threatens populations of several North American bat species. The fungal disease was first observed in 2006 and has since caused the death of nearly six million bats. The disease, commonly known as white-nose syndrome, is characterized by a cutaneous infection with P. destructans causing erosions and ulcers in the skin of nose, ears and/or wings of bats. Previous studies based on sequences from eight loci have found that isolates of P. destructans from bats in the US all belong to one multilocus genotype. Using the same multilocus sequence typing method, we found that isolates from eastern and central Canada also had the same genotype as those from the US, consistent with the clonal expansion of P. destructans into Canada. However, our PCR fingerprinting revealed that among the 112 North American isolates we analyzed, three, all from Canada, showed minor genetic variation. Furthermore, we found significant variations among isolates in mycelial growth rate; the production of mycelial exudates; and pigment production and diffusion into agar media. These phenotypic differences were influenced by culture medium and incubation temperature, indicating significant variation in environmental condition - dependent phenotypic expression among isolates of the clonal P. destructans genotype in North America. [ABSTRACT FROM AUTHOR]

Mushrooms that are morphologically indistinguishable from Russula virescens (Schaeff.) Fr. are among the most popular wild edible mushrooms in Yunnan province, southwestern China. However, almost nothing is known about their biology. This study investigated the diversity and population genetics of a R. virescens ally from Yunnan. A total of 210 samples were collected from 13 geographical locations throughout the main distribution range in Yunnan. The patterns of genetic variation within and among these geographic populations were analyzed using sequences from three nuclear and two mitochondrial DNA fragments. Analysis of the ITS sequences revealed that samples from Yunnan showed 3–6% sequence difference from R. virescens samples from North America and Europe and formed a distinct clade. Our multilocus population genetic analyses suggested frequent gene flow among geographic populations of the R. virescens ally in Yunnan. Interestingly, the nuclear and mitochondrial genes exhibited different levels of gene flow and recombination. We discuss the implications of our results for understanding speciation, reproduction and conservation of this important biological resource. [ABSTRACT FROM AUTHOR]