Multi-Gene Phylogeny and Morphology Reveal Haplohelminthosporium gen. nov. and Helminthosporiella gen. nov. Associated with Palms in Thailand and A Checklist for Helminthosporium Reported Worldwide

Abstract

Palms (Arecaceae) are substrates for a highly diverse range of fungi. Many species are known as saprobes and many are important plant pathogens. Over the course of our studies of micro-fungi from palms in Thailand, two new taxa were discovered. Morphological characteristics and phylogenetic analyses of combined ITS, LSU, SSU, and tef1-α sequence data revealed their taxonomic positions within Massarinaceae. There are currently ten genera identified and accepted in Massarinaceae, with the addition of the two new genera of Haplohelminthosporium and Helminthosporiella, that are introduced in this paper. Each new genus is provided with a full description and notes, and each new taxon is provided with an illustration for the holotype. A list of identified and accepted species of Helminthosporium with morphology, host information, locality, sequence data, and related references of Helminthosporium reported worldwide is provided based on records in Species Fungorum 2021. This work provides a micro-fungi database of Haplohelminthosporium, Helminthosporiella, and Helminthosporium which can be modified and validated as new data come to light.

Synhelminthosporium gen. et sp. nov. and Two New Species of Helminthosporium (Massarinaceae, Pleosporales) from Sichuan Province, China

“…For instance, H. cynodontis was reassigned to the genus Bipolaris (Pleosporaceae, Pleosporales) due to the production of sympodial conidiogenous cells and by having darkly pigmented conidiogenous loci [46]. Recently, Konta et al [7] accepted 216 Helminthosporium species, however many species are identified only based on morphological studies, and only 25 species have sequence data. The lack of a large amount of molecular data is mainly because most species were introduced before the advent of Sanger sequencing.…”

“…In addition, H. hispanicum is fungicolous and grows on old conidiomata of Juglanconis juglandina [8], whereas H. chengduense (UESTCC 22.0024) is saprobic on decaying wood in damp environments. Konta et al [7] summarized the morphological characteristics of 216 Helminthosporium species. Among them, only H. asterinum, H. longisinuatum, and H. makilingense produce larger conidia than H. chengduense UESTCC 22.0024.…”

“…In addition to Helminthosporium, ten other genera are accepted in the family Massarinaceae (Pleosporales, Dothideomycetes), i.e., Byssothecium, Haplohelminthosporium, Helminthosporiella, Massarina, Mirohelminthosporium, Pseudodidymosphaeria, Pseudosplanchnonema, Semifissispora, Stagonospora, and Suttonomyces [5,6]. Based on multi-locus phylogenetic analysis, Konta et al [7] confirmed that Helminthosporium is polyphyletic, where members were mixed with other taxa of Byssothecium, Helminthosporiella, and Pseudosplanchnonema. Most Helminthosporium species are saprobes feeding on dead or decaying woods [7,8].…”

“…Based on multi-locus phylogenetic analysis, Konta et al [7] confirmed that Helminthosporium is polyphyletic, where members were mixed with other taxa of Byssothecium, Helminthosporiella, and Pseudosplanchnonema. Most Helminthosporium species are saprobes feeding on dead or decaying woods [7,8]. However, one species, H. solani is an economically important pathogen causing silver scurf disease in potatoes worldwide [9,10].…”

“…However, one species, H. solani is an economically important pathogen causing silver scurf disease in potatoes worldwide [9,10]. Helminthosporium species are commonly collected from leaves and decaying wood in terrestrial habitats [7,8,11] and rarely reported in freshwater habitats [12].…”