Systematic studies on the heterobasidiomycetes (Agaricomycotina, Basidiomycota, Fungi) of Kerala

Abstract

Heterobasidiomycetes are a polyphyletic group of fungi having jelly-like basidiocarp, complex dolipore septum with parenthesomes, septate basidia, and basidiospores capable of producing secondary spores and/or yeast-like cells. Heterobasidiomycetes (Agaricomycotina) generally called as jelly fungi are distributed in the following classes: Agaricomycetes, Dacrymycetes, and Tremellomycetes. Heterobasidiomycetous fungi exhibit diversity in basidiocarp shape, size, colour and utilize various substrata. Ecological features of heterobasidiomycetes like habitat, mode of nutrition and associating organisms vary significantly in different classes and orders. Heterobasidiomycetes include economically important taxa with edibility and proven bioactivity. From Kerala, Rangaswami et al. (1970) reported one species and Mohanan (2011) reported ten species of heterobasidiomycetes. Comprehensive studies of this group are lacking in Kerala State. Hence, a systematic study of the heterobasidiomycetes fungi of Kerala was attempted. Specimens used in the study were collected from different localities of Kerala State during 2018-2024. Morphological and molecular characterizations were done. The newly generated sequences were deposited in GenBank (www.ncbi.nlm.nih.gov) database. Phylogenetic analysis to elucidate the relationships of taxa collected in the study was done. Pure cultures of 20 species were generated and maintained at Fungal Diversity laboratory of the Zamorin’s Guruvayurappan College. All the collections (including holotype materials) have been deposited at the Zamorin’s Guruvayurappan College herbarium (ZGC), Kozhikode. The present systematic study on heterobasidiomycete documented 47 species belonging to 11 genera, 7 families, 4 orders. Detailed morphological descriptions, comprehensive taxonomic accounts, macroscopic and microscopic photographs, and keys to the heterobasidiomycetes group were prepared. Three species collected during the study have been formally proposed as new to science. Seven species were found as hitherto undescribedand may represent species new to science (Sebacina species, Dacrymyces species 1, Dacrymyces species 2, Tremella species 1, Tremella species 2 and Tremella species 3 and Vishniacozyma species). Two taxa were identified only up to family level and belonged to Auriculariaceae, and Cryptococcaceae. These two taxa could not place in a genus because they exhibited phylogenetic distinction from all the heterobasidiomycete genera described so far. Fifty five molecular sequences were newly generated and phylogenetic analysis of Auriculariales, Sebacinales, Dacrymycetes, and Tremellomycetes were conducted for accurate identification of species. This study forms the first phylogenetically supported comprehensive treatment of heterobasidiomycetes from India.