Understanding the Diversity of Pestalotiopsis sensu lato Fungi Associated with Entomopathogenic Fungi in Taiwan
Sheng-Yu Hsu1, Yuan-Cheng Xu1, Yu-Chen Lin1, Wei-Yu Chuang1, Shiou-Ruei Lin2 and Hiran A. Ariyawansa1*
1Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
2Section of Tea Agronomy, Tea Research and Extension Station, Council of Agriculture, Taoyuan City, Taiwan
Pestalotiopsis sensu lato fungi are widely distributed and often occur as endophytes, saprobes, and pathogens of many plants. Taxa contained in Pestalotiopsis sensu lato are classified into three genera viz. Pestalotiopsis, Pseudopestalotiopsis, and Neopestalotiopsis based on the conidial colour of their median cells and multi-locus molecular phylogenies. During a biodiversity investigation of entomopathogenic fungi, 12 Pestalotiopsis sensu lato strains were identified to be associated with fruiting bodies of Beauveria, Ophiocordyceps, and Tolypocladium in different regions of Taiwan between 2018 and 2021. These strains were evaluated morphologically, and multi-locus phylogenetic analyses of the ITS (internal transcribed spacer), tef1-α (translation elongation factor 1-α), and tub2 (beta-tubulin) gene regions were conducted for genotyping. The results revealed three well-classified taxa and five tentative clades in Pestalotiopsis and Neopestalotiopsis. One novel species, Pestalotiopsis manyueyuanani, and one new record, P. hispanica, were reported for the first time in Taiwan. Additionally, P. formosana and unclassified strains of Pestalotiopsis and Neopestalotiopsis were identified based on similarities in phylogeny and morphology. However, the data obtained in the present study suggest that the currently recommended loci for species delimitation of Pestalotiopsis sensu lato do not deliver reliable or adequate resolution of tree topologies. The in-vitro mycelial growth rates of selected strains from these taxa had an optimum temperature of 25 ℃, but growth ceased at 5 ℃ and 35 ℃ while all the strains grew faster under alkaline than acidic or neutral pH conditions. This study provides the first assessment of Pestalotiopsis sensu lato fungi associated with entomopathogenic taxa.