Identification and analyses of the chemical composition of a naturally occurring albino mutant chanterelle

Genome resequencing and transcriptome analysis reveal the molecular mechanism of albinism in Cordyceps militaris

Light is an important regulator of most fungal life activities and transmits signals through certain photoreceptor proteins such as phytochromes and cryptochromes. However, the light response mechanism varies across different fungi. The WCC complex composed of white collar-1 (WC-1) and white collar-2 (WC-2) is considered to be the key factor regulating fungal albinism. The photoreceptor protein Vivid (VVD) is the negative regulator of the WCC complex. In this study, we discovered an albino mutant (Alb) generated by ⁶⁰Co-γ-ray irradiation from Cordyceps militaris (C. militaris). This mutant showed albinism of the mycelia and fruiting bodies under light, and the fruiting bodies developed normally. However, this phenotype in Alb differed from that in the CmWC-1 mutant. This suggests that CmWC1 may not be mutated in Alb. A mutated polyketide synthase (CmPKS) was found through genome resequencing analysis. CmPKS was significantly induced by a light signal, and its mutation reduced melanin accumulation in C. militaris. In addition, we found that a zinc-finger domain-containing protein (CmWC-3) was induced by a light signal and interacted with CmWC-1 and CmVVD. Moreover, CmWC-2 also interacted with CmWC-1 to form the WCC complex and was inhibited by CmVVD. In addition, CmWC-3 directly bound with the CmPKS promoter, but CmWC1 did not. These results suggest that albinism and fruiting body development are two independent processes; the WCC complex of CmWC-1 with CmWC-3 regulates CmPKS expression to regulate color change, whereas CmWC-1 with CmWC-2 affects fruiting body development via the carotenoid pathway. These findings will help us to better understand the albinism mechanism of C. militaris.

New reports, new species, and high diversity of Cantharellus in the southern Appalachians

Chanterelles (genus Cantharellus) are among the most popular wild edible mushrooms worldwide. Efforts to understand chanterelle diversity have yielded numerous new species in recent years, particularly in eastern North America. We constructed a multilocus phylogeny including all described temperate species of Cantharellus and newly collected specimens from the eastern United States with an emphasis on southern Appalachia. We describe a new species, Cantharellus vicinus, an oak-associated chanterelle known only from lower-elevation areas in east Tennessee, based on phylogenetic and morphological data. Cantharellus vicinus is characterized by a compact stature, bright yellow hymenophore that turns salmon when mature, white stipe, and pale yellow pileus with a whitish bloom. The southeastern Cantharellus minor f. intensissimus is elevated to species level based on morphological and molecular evidence. The taxon is epitypified due to the sterile state of the holotype and ambiguity concerning application of the name. Evaluation of genetic diversity and gene conflict within Cantharellus camphoratus shows that it is a widespread species with populations in Atlantic Canada, the southeastern United States, and Japan. Similarly, C. cibarius and C. tenuithrix form complexes and may be more geographically widespread than previously thought. Additionally, we report the first known instances of Cantharellus betularum, C. corallinus, and C. altipes from the southern Appalachian Mountains.

Genetic Analyses of Discrete Geographic Samples of a Golden Chanterelle in Canada Reveal Evidence for Recent Regional Differentiation

The wild edible mushroom Cantharellus enelensis is a recently described species of the golden chanterelles found in eastern North America. At present, the genetic diversity and population structure of C. enelensis are not known. In this study, we analyzed a total of 230 fruiting bodies of C. enelensis that were collected from three regions of Canada: near the east and west coasts of Newfoundland (NFLD), with 110 fruiting bodies each, and around Hamilton, Ontario (10 fruiting bodies). Among the 110 fruiting bodies from each coast in NFLD, 10 from 2009 were without specific site information, while 100 sampled in 2010 were from each of five patches separated by at least 100 m from each other. Each fruiting body was genotyped at three microsatellite loci. Among the total 28 multilocus genotypes (MLGs) identified, 2 were shared among all three regions, 4 were shared between 2 of the t3hree regions, and the remaining 22 were each found in only 1 region. Minimal spanning network analyses revealed several region-specific MLG clusters, consistent with geographic specific mutation and expansion. Though the most frequently observed MLGs were shared among local (patch) and regional populations, population genetic analyses revealed that both local and regional geographic separations contributed significantly to the observed genetic variation in the total sample. All three regional populations showed excess heterozygosity; for the eastern NFLD population, we reject the null hypothesis of Hardy–Weinberg equilibrium (HWE) at all three loci. However, the analyses of clone-corrected samples revealed that most loci were in HWE. Together, our results suggest that the three discrete regional populations of C. enelensis were likely colonized from a common refugium since the last ice age. However, the local and regional populations are diverging from each other through mutation, drift, and selection at least partly due to heterozygous advantage.