Putative palm pathogens: Novel species and new host records of leaf disease-associated microfungi (Ascomycota) on Nypa fruticans in Thailand

Abstract

Nypa fruticans is a true mangrove species that provides numerous economic and ecological contributions to the mangrove ecosystem. Various studies have dealt with fungi associated with mangrove palms; however, most of these are saprobes, and few studies have explored disease-associated microfungi. In this study, fungi were isolated from symptomatic leaves of Nypa fruticans collected in mangrove estuaries in Prachuap Khiri Khan, Thailand.

From the 17 isolates obtained, four species were identified using combined morpho-cultural characteristics and molecular phylogenetic analyses; different subsets of loci (from ITS, LSU, ACT, CAL, CHS - 1, GAPDH, HIS 3, RPB 2, TEF 1 - α, and TUB 2) were used per species. Two new species, Brunswickiella nypae and Pestalotiopsis nypae, are described, and two new host records of Colletotrichum siamense and Diaporthe arecae are given.

We also provide an updated worldwide list of reported microfungi on N. fruticans. This study addresses a gap in the leaf disease-associated microfungi on N. fruticans and provides a comprehensive overview of the diversity of fungal species on this brackish water palm. By documenting fungal diversity and potential pathogens, our findings support biodiversity conservation and sustainable ecosystem management, directly contributing to SDG 14 (Life Below Water) and SDG 15 (Life on Land) and indirectly to SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action) through the protection of mangrove health and resilience.