New endophytic Toxicocladosporium species from cacti in Brazil, and description of Neocladosporium gen. nov.

Brazil harbours a unique ecosystem, the Caatinga, which belongs to the tropical dry forest biome. This region has an important diversity of organisms, and recently several new fungal species have been described from different hosts and substrates within it. During a survey of fungal endophyte diversity from cacti in this forest, we isolated cladosporium-like fungi that were subjected to morphological and multigene phylogenetic analyses including <i>actA</i>, ITS, LSU, <i>rpb2</i> and <i>tub2</i> gene sequences. Based on these analyses we identified two new species belonging to the genus <i>Toxicocladosporium</i>, described here as <i>T. cacti</i> and <i>T. immaculatum</i> spp. nov., isolated from <i>Pilosocereus gounellei</i> subsp. <i>gounellei</i> and <i>Melocactus zehntneri</i>, respectively. To improve the species recognition and assess species diversity in <i>Toxicocladosporium</i> we studied all ex-type strains of the genus, for which <i>actA</i>, <i>rpb2</i> and <i>tub2</i> barcodes were also generated. After phylogenetic reconstruction using five loci, we differentiated 13 species in the genus. <i>Toxicocladosporium velox</i> and <i>T. chlamydosporum</i> are synonymized based on their phylogenetic position and limited number of unique nucleotide differences. Six strains previously assigned to <i>T. leucadendri</i>, including the ex-type strain (CBS 131317) of that species, were found to belong to an undescribed genus here named as <i>Neocladosporium</i> gen. nov., with <i>N. leucadendri</i> comb. nov. as type species. Furthermore, this study proposes the <i>actA</i>, ITS, <i>rpb2</i> and <i>tub2</i> as main phylogenetic loci to recognise <i>Toxicocladosporium</i> species.