| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1145-2 | ||||
Resumo:The recently described fungus Diaporthe vochysiae was originally isolated as an endophyte from the medicinal plants Vochysia divergens and Styphnodendron adstringens of the Pantanal and Cerrado biomes, respectively. In bioprospecting studies, D. vochysiae isolates likely represent promising sources of novel and bioactive compounds, since the type-strain of this species (LGMF1583 / CMRP3911) was described to produce two novel carboxamides (vochysiamides A and B). D. vochysiae is a genetically and macro-morphologically diverse species with 56 known isolates housed at the NAPI CMRP/Taxonline collection, and this genetic and morphological diversity could be correlated with a potential diversity in the bioactivity profile of the compounds produced by the isolates. In this sense, a detailed investigation of the genetic diversity and proper delimitation of species boundaries is an important step to better understand D. vochysiae species and guide further bioprospecting approaches. Multigene phylogenetic analyses were performed using a concatenated alignment including TEF (translation elongation factor), TUB (&beta tubulin) CAL (calmodulin) and HIS (histone 3) sequences, under both maximum likelihood (bootstrap values) and Bayesian inference (posterior probability values) methods, for better confidence and robustness in the delimitation of the Diaporthe species. Analyses also included representative strains from the closest sister species to D. vochysiae, which all belong to the recently proposed monophyletic Diaporthe sojae clade, with Diaporthe ganjae as outgroup. As Diaporthe is described as a highly diverse genus, working with species complexes or ingroup clades (such as Diaporthe sojae clade) instead of the whole genus is usually recommended for better species delimitation, as analyses including only closer taxa are thought to facilitate the resolution of intraspecific relations and relationships among very closely related taxa. The results so far indicate that there are likely five groups within the larger monophyletic D. vochysiae sensu lato group, which could indicate the existence of more than one species. The first group, which contains the type strain (LGMF1583 /CMRP3911) is apparently the largest, polytomic and not very diverse, while the second group appears to be smaller and more genetically diverse, the other three groups appear to be progressively removed from the other two, not forming larger groups among themselves and contain only two isolates each. Coalescent analysis was performed to assess whether the groupings found within D. vochysiae sensu lato are real and the results so far seem to corroborate the groups observed in the phylogenetic analysis. In order to assess if the status of such groups as different species or subspecies, further analyses combining haplotype evaluation, metabolite profiling, and bioactivity assays will be performed. Moreover, representative isolates from the four new ingroups observed in D. vochysiae sensu lato will have their genome sequenced for the characterization of biosynthetic gene clusters and comparative genomics analyses, which will enable further comparisons and a better evaluation of their bioactive potential.
Palavras-chave: Phylogeny, Diaporthe, Bayesian Inference, Maximum Likelihood, Coalescent analysis Agência de fomento:CAPES | |||||