Clonostachys itumiriensis, a novel species from the Brazilian Cerrado identified through matrix-assisted laser desorption ionization time-of-flight mass spectrometry and multilocus phylogeny

Species of Clonostachys and Sesquicillium are commonly found in soils and associated with plants as saprophytes or endophytes. Clonostachys also contains mycoparasitic species used as biocontrol agents. Thirty-three isolates of both genera, obtained from different substrates and locations in Brazil, were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and phylogenetic analysis based on acl1 gene sequences. Ex-type and reference strains of eight species were also included in the MALDI-TOF MS analyses. Multivariate cluster analysis of MALDI-TOF MS data grouped the reference strains in species-specific clusters and classified 26 isolates into clusters corresponding to seven known species, Clonostachys chloroleuca (n = 1), C. farinosa (n = 13), C. pseudochroleuca (n = 5), C. rhizophaga (n = 1), C. rogersoniana (n = 2), C. rosea (n = 2), and Sesquicillium lasiacidis (n = 2). Two additional clusters were composed of three and four isolates having morphological characteristics resembling C. compactiuscula. Multilocus phylogenetic analyses using five loci (acl1, tub2, tef1, rpb1, rpb2) grouped the seven strains in a single lineage consisting of two subclades and corresponding to a novel phylogenetic species, herein described as Clonostachys itumiriensis, sp. nov. This species belongs to subgenus Bionectria and is phylogenetically close to C. cylindrica, C. divergens, C. hongkongensis, C. rogersoniana, and C. samuelsii. Strains of this species were mostly obtained from leaf litter. Our results show the robustness of MALDI-TOF MS for delimiting known and novel species of Clonostachys and validate the use of this technique as a tool for classifying fungi from diverse substrates.