RESUMO

Caves are unique environments characterized by spatial limitations, partial or total absence of direct light, and scarcity of organic carbon and nutrients. Caves are shelters for a variety of adapted animals and microorganisms such as fungi, many of which are still unknown. Amphichorda is a fungal genus belonging to the family Bionectriaceae, which includes cave-dwelling and entomopathogenic species with biotechnological applications. In this study, a new fungal species was identified using morphological and multi-locus phylogenetic analyses of the ITS, LSU, and TEF loci, in the Gruta Velha Nova limestone cave located in the Southern Espinhaço Range, Monjolos, Minas Gerais, Brazil. During the exposure of potato dextrose agar plates to the cave environment, an insect from the family Rhaphidophoridae passed by and fed on the culture medium, resulting in three fungal isolates. Phylogenetic analyses showed that these isolates formed a clade distinct from all known species, leading us to introduce a new species, Amphichorda monjolensis, which may be associated with this insect. Here, we also proposed two new combinations for species of acremonium-like fungi in the Bionectriaceae: Bulbithecium globosisporum (synonym: Acremonium globosisporum) and Hapsidospora curva (synonym: Acremonium curvum). The discovery of A. monjolensis highlights the potential of caves as shelters for new species with significant biotechnological importance.

Assuntos

Cavernas , DNA Fúngico , Filogenia , Cavernas/microbiologia , Brasil , DNA Fúngico/genética , Animais , Carbonato de Cálcio , Acremonium/genética , Acremonium/classificação , Acremonium/isolamento & purificação

RESUMO

Caves are underground and natural environments mainly found in rocky terrain. Caves have a very specific microclimate, which benefits the occurrence of specific fungi. In recent studies, researchers have observed that caves harbour a great diversity of fungi. However, studies on fungal diversity in Brazilian caves are still incipient. In September 2019, airborne spore and soil samples were collected from the Monte Cristo cave, in the Southern Espinhaço Range, Diamantina, Minas Gerais state, Brazil. Two Cladosporium single-spore isolates, among other genera, were obtained from these samples. This study aimed to characterise these two fungal isolates based on their DNA sequence data and morphology. Phylogenetic analyses of the rDNA-ITS, ACT and TEF1-α loci revealed that the isolates belonged to the Cladosporium cladosporioides species complex. Both isolates did not cluster with any known species and were formally described and named herein as C. diamantinense and C. speluncae. This study presents taxonomic novelties and contributes to the knowledge about the fungal diversity in Brazilian caves.

Assuntos

Cladosporium , Brasil , Cladosporium/genética , Filogenia , DNA Ribossômico

RESUMO

Coconut palm (Cocos nucifera L.) is one of the most important perennial tropical crops. Stem-end rot is the major postharvest disease of coconut in Brazil. The fungus Lasiodiplodia theobromae is the only species that has been reported to be associated with this disease. However, a comprehensive study elucidating the true identity of this pathogen with molecular tools has never been conducted. In recent years, new species of Lasiodiplodia have been proposed after molecular studies were performed, indicating the existence of a species complex. The aims of this research were to study the etiology of the postharvest stem-end rot of immature coconut based on a combination of morphological and phylogenetic analyses, to establish the phylogenetic position of such taxa, and to assess the pathogenicity of each taxon. Four species were identified: L. brasiliense, L. egyptiacae, L. pseudotheobromae, and L. theobromae. All of the species were distinguished morphologically and phylogenetically and were proven to be pathogenic to coconut following artificial inoculation. L. theobromae was the most common and the most aggressive species. This study represents the first report of three additional species of Lasiodiplodia as causal agents of postharvest stem-end rot of immature coconut in Brazil.