Four new species of Trichoderma (Hypocreaceae, Hypocreales) discovered in the staple food bamboo of pandas

<i>Trichoderma</i> fungi are significant saprophytic resources in nature, with only a minority of species documented as pathogenic fungi. Due to their widespread distribution, this genus of fungi has attracted considerable attention in recent years. During an investigation of fungal resources within the staple food bamboo species for giant pandas in China conducted from 2023 to 2024, a high diversity of <i>Trichoderma</i> species was observed. In this study, eight collected specimens were compared morphologically with known species, and DNA sequence analysis was performed using a multi-gene (ITS, <i>tef</i>1-α, and <i>rpb</i>2) dataset to establish phylogenetic relationships, ultimately leading to the identification of four <i>Trichoderma</i> species. The research uncovered four novel <i>Trichoderma</i> species: <i>Trichoderma bashania</i>, <i>T. fargesia</i>, <i>T. mianyangensis</i> and <i>T. yaanensis</i>. Phylogenetic analysis revealed that each of these new species forms a distinct lineage, with <i>Trichoderma bashania</i>, <i>T. fargesia</i>, <i>T. mianyangensis</i> and <i>T. yaanensis</i> all belonging to the Koningii section. All these newly identified species were isolated from the litter of the staple food bamboo species for giant pandas. This study provides morphological descriptions and illustrations of these four new species, along with DNA phylogenetic relationships based on the analysis of the multi-gene dataset. The findings indicate that <i>Trichoderma</i> fungi are widely present in the ecosystem of the staple food bamboo species for giant pandas and warrant close attention.