Starmera pilosocereana sp. nov., a yeast isolated from necrotic tissue of cacti in a sandy coastal dune ecosystem

Abstract

Two strains of a novel cactophilic yeast species were isolated from the columnar cactus Pilosocereus arrabidae in a sand dune ecosystem in Rio de Janeiro, Brazil. Phylogenetic analysis of sequences of the large subunit rRNA gene D1/D2 domains showed that the strains represent a sister species to Starmera caribaea, from which it differs by 21 nt substitutions and two indels. The novel species is heterothallic and the asci are deliquescent with the formation of two to four hat-shaped ascospores. The name Starmera pilosocereana sp. nov. is proposed for the species. The type strain is UFMG-CM-Y316T ( = CBS 13266T) and the allotype is UFMG-CM-Y346a ( = CBS 13265). The Mycobank number is MB 810683. In addition, Candida stellimalicola belonging to the Starmera clade, is reassigned to Starmera as a new combination.

Starmera foglemanii sp. nov. and Starmera ilhagrandensis sp. nov., two novel yeast species isolated from ephemeral plant substrates

“…Starmera foglemanii was isolated from fruit and rotting tissues of two species of the genus Opuntia in the region of South Brazil. The species was not found in extensive collections of rotting tissues of several species of cacti, including members of the genus Opuntia , in other regions in Brazil, where the prevalent yeasts were P. cactophila, C. sonorensis, Clavispora opuntiae and species of the Sporopachidermia cereana complex [5; C. A. Rosa, unpublished data]. It would therefore seem that the species is restricted to cacti growing in Southern Brazil.…”

“…Cactophilic species of the genus Starmera occur as haploid or diploid strains [5]. UFMG-CM-Y6622 is self-sporulating.…”

“…The remaining species, Starmera stellimalicola, was isolated from a fruit of star apple ( Averrhoa carambola, Oxilidaceae) in Thailand. The cactophilic species require an organic source of sulfur for growth, but S. stellimalicola does not [4–6]. Species of the other subclade, Starmera quercuum, Starmera dryadoides, Candida berthetii and Candida dendrica , grow well in the absence of added l -methionine or l -cysteine [4, 6].…”

“…The Starmera clade contains five sexual species, S. amethionina, S. pachycereana, S. caribaea, S. pilosocereana, S. quercuum and S. dryadoides. C. berthetii , C. dendrica , C. laemsonensis, and the former Candida stellimalicola do not produce spores in conventional sporulation media [4, 5]. P. nongkratonensis produces one to three, usually two, hat-shaped ascospores.…”

“…Freitas et al . [5] transferred C. stellimalicola to the genus Starmera , but expressed the view that C. berthetii , C. dendrica , and closely related species of the genus Starmera , as indicated by Kurtzman [4], could eventually be reassigned to a separate genus.…”