Novel Hypocrealean Fungi from Rhizophoraceae, Neocosmospora mangrovei sp. nov. and Neocosmospora ceriopis sp. nov., and their Antifungal Activity against Anthracnose Pathogen Colletotrichum spp.

Abstract

Neocosmospora is a fungus genus that contains saprobes, endophytes, and pathogens in the family Nectriaceae. Prior to this study, 113 morphological species belonging to this genus have been described and published. In this study, we reported two new species of fungus, Neocosmospora mangrovei (MFLUCC 17–0253; MFLUCC 17–0257) and N. ceriopis (MFLUCC 17–0259) that were isolated from the mangrove habitats in the Southern part of Thailand. Phylogenetic analyses of the combined ITS, EF-1α, RPB2, and LSU regions showed that the new species clustered within the Neocosmospora clade with strong statistical support. Detailed descriptions and illustrations, pairwise homoplasy index (PHI) test, and a phylogenetic tree showing the position of both new species are provided. In addition, both new species showed the potential to be used as biocontrol agents against Colletotrichum spp. The N. mangrovei, MFLUCC 17–0253 exhibited strong antifungal activity against C. truncatum, MFLUCC CG-0064 e.g., 100% of mycelium growth inhibition, 90.83% inhibition of spore germination, and 100% reduction hyphae expansion. The N. ceriopis MFLUCC 17–0259 exhibited antifungal activity against C. acutatum, MFLUCC CC-0036 e.g., 69.39% of mycelium growth inhibition, 79.39% inhibition of spore germination, and 96.42% reduction hyphae expansion. Overall, these findings suggested novel species of Neocosmospora that had the capacity to produce various classes of biometabolites including 2,3-hydro-5-hydroxy-8-methoxy-2,4-dimethylnapthol-[1,2-b]-furan-6,9-dione, 2-methoxy-6-methyl-7-acetonyl-8-hydroxy-1,4-maphthalenedione, 5,8-dihydroxy-7-acetonyl-1,4-naphthalenedione, anhydrojavanicin, and fusarnaphthoquinones that can provide an antimicrobial activity that could have the potential in playing a big role in treating anthracnose disease.