Novel Endophytic Pestalotioid Species Associated with Itea in Thailand

Jutamart Monkai ¹ Rungtiwa Phookamsak ^2* Darbhe Jayarama Bhat ³ Toe Swe Zin Ei ¹ Jian Chu Xu ² Saisamorn Lumyong ^1*

• ¹ Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
• ² Centre for Mountain Futures (CMF), Kunming Institute of Botany, Kunming, China
• ³ Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia

Endophytic fungi are well-known as a fascinating host-associated fungal group that can enhance plant growth and fitness by producing various bioactive secondary metabolites. They constitute an excellent source of industrial enzymes and potential secondary metabolite synthesis, useful in green agriculture, biotechnology and pharmaceuticals. Itea is a valuable plant genus since it naturally contains rare sugar; however, endophytic fungi associated in this host have not yet been documented. In the present study, eleven strains of endophytic fungi were isolated and primarily identified as pestalotioid taxa based on morphological characteristics exhibited in vitro. Eleven strains of Pestalotiopsis-like taxa were isolated from the healthy leaves, stems and roots of Itea japonica and I. riparia from Chiang Mai Province, Thailand. Species delimitation was based on morphology, multiloci phylogeny of a concatenated ITS, tub2 and tef1-α sequence data, and nucleotide polymorphism analyses. Neopestalotiopsis iteae and Pseudopestalotiopsis iteae are proposed as new species on Itea japonica and I. riparia, respectively. Neopestalotiopsis chrysea, N. haikouensis and Pestalotiopsis jinchanghensis are described as new records on I. riparia. Due to the conspecific relationship based on multiloci phylogeny and identically nucleotide pairwise of sufficient gene regions, several species are synonymized including Neopestalotiopsis cercidicola and N. terricola as N. haikouensis, N. umbrinospora as N. chrysea, and Pestalotiopsis zhaoqingensis as P. jinchanghensis. The updated phylogenetic trees, nucleotide comparisons and morphological descriptions are herein provided and discussed for the taxonomic placements of these new species and records. This study is the first to investigate Itea endophytes in Thailand and it unveils intra- and inter-specific relationships of pestalotioid species, which need further reappraisal of ambiguous taxa.