Pine trees play a crucial role in the forests of Sichuan Province, boasting rich species diversity and a lengthy evolutionary history. However, research and investigation on fungi associated with pine trees are insufficient. This study investigated the diversity of hyphomycetes fungi associated with pine trees in Sichuan Province, China. During the survey, we collected five specimens of hyphomycetes from branches and bark of species of Pinus. Five barcodes were selected for study and sequenced, including ITS, SSU, LSU, TEF1, and RPB2. Morphological examination and multi-locus phylogenetic analyses revealed three new species, viz. Catenulostroma pini sp. nov. within Teratosphaeriaceae, Kirschsteiniothelia longisporum sp. nov. within Kirschsteiniotheliaceae, Sporidesmiella sichuanensis sp. nov. within Junewangiaceae, and two known species, Paradictyoarthrinium diffractum and P. hydei within Paradictyoarthriniaceae, which are the new host records from Pinus species. Catenulostroma pini, distinguished from other species in the genus by its unique morphology, has three conidial morphologies: small terminal helicoconidia, scolecoconidia with many septa, and phragmoconidia conidia. Kirschsteiniothelia longisporum has longer spores when compared to the other species in the genus. According to phylogenetic analysis, Sporidesmiella sichuanensis formed an independent clade sister to S. aquatica and S. juncicola, distinguished by differences in conidial size.

The present study explored the potential role of cold-regulated plasma membrane protein COR413PM1 isolated from Saussurea involucrata (Matsum. & Koidz)(SikCOR413PM1), in enhancing cotton (Gossypium hirsutum) tolerance to cold and drought stresses through transgenic methods. Under cold and drought stresses, the survival rate and the fresh and dry weights of the SikCOR413PM1-overexpressing lines were higher than those of the wild-type plants, and the degree of leaf withering was much lower. Besides, overexpressing SikCOR413PM1 overexpression increased the relative water content, reduced malondialdehyde content and relative conductivity, and elevated proline and soluble sugar levels in cotton seedlings. These findings suggest that SikCOR413PM1 minimizes cell membrane damage and boosts plant stability under challenging conditions. Additionally, overexpression of this gene upregulated antioxidant enzyme-related genes in cotton seedlings, resulting in enhanced antioxidant enzyme activity, lowered peroxide content, and reduced oxidative stress. SikCOR413PM1 overexpression also modulated the expression of stress-related genes (GhDREB1A, GhDREB1B, GhDREB1C, GhERF2, GhNAC3, and GhRD22). In field trials, the transgenic cotton plants overexpressing SikCOR413PM1 displayed high yields and increased environmental tolerance. Our study thus demonstrates the role of SikCOR413PM1 in regulating stress-related genes, osmotic adjustment factors, and peroxide content while preserving cell membrane stability and improving cold and drought tolerance in cotton.

Pleosporales is a highly diverse (and the largest) order in Dothideomycetes, and it is widespread in decaying plants in various environments around the world. During a survey of fungal diversity in Sichuan Province, China, specimens of hyphomycetous and Thyridaria-like fungi were collected from dead branches of pine trees and cherry trees. These taxa were initially identified as members of Massarinaceae and Thyridariaceae through morphological examination. Phylogenetic analyses of the Thyridariaceae, combining ITS, SSU, LSU, RPB2, and TEF1 sequence data, indicated a distinct clade sister to Pseudothyridariella and Thyridariella, distinct from any genus in the family. Thus, a new genus, Vaginospora, is proposed to accommodate the type species Vaginospora sichuanensis, which is characterized by semi-immersed globose to oblong ascomata with an ostiolar neck, cylindrical to clavate asci with an ocular chamber, and hyaline to dark brown, fusiform, 3–5-transversely septate ascospores with an inconspicuous mucilaginous sheath. Based on the morphological comparisons and multi-locus phylogenetic analyses (ITS, SSU, LSU, RPB2, and TEF1) of the Massarinaceae, we have identified three collections belonging to the genus Helminthosporium, leading us to propose H. filamentosa sp. nov., H. pini sp. nov., and H. velutinum as a new host record. According to Phylogenetic analysis, H. pini formed an independent clade sister to H. austriacum and H. yunnanense, and H. filamentosa represents the closest sister clade to H. quercinum. Helminthosporium pini is distinct from H. austriacum by the shorter conidiophores and H. yunnanense by the longer and wider conidia. The H. filamentosa differs from H. quercinum in having longer conidiophores and smaller conidia. This study extends our understanding of diversity within Thyridariaceae and Helminthosporium. Our findings underscore the rich biodiversity and potential for discovering novel fungal taxa within these groups.