705-2Yeast community associated to Melipona quinquefasciata Lepeletier, a stingless bee.
Autores:Paula de Souza Sao Thiago Calaça (FUNED - Fundação Ezequiel Dias) ; Débora Gonçalves Chaves (UFMG - Universidade Federal de Minas Gerais) ; Laila Evangelista de Almeida Fernandes (FUNED - Fundação Ezequiel Dias) ; Esther Margarida Alves Ferreira Bastos (FUNED - Fundação Ezequiel Dias) ; Yasmine Antonini (UFOP - Universidade Federal de Ouro Preto) ; Carlos Augusto Rosa (UFMG - Universidade Federal de Minas Gerais)


Meliponins are social bees, which occur mainly in Neotropics and are important pollinators of native and cultivated plant species. Melipona quinquefasciata belongs to this group and build its nests underground. This study aimed to investigate the yeast community living associated to M. quinquefasciata nests. Collections were made in natural nests located in Parque Estadual Veredas do Peruaçú, with a Cerrado vegetation northern Minas Gerais State. Three aseptic collections of stored pollen (0.1g), ripened and unripened honey (0.1μl) were made in July, September of 2009 and January of 2010. Furthermore, adult bees were allowed to walk 15 to 30 minutes on yeast extract-malt extract (YM) plates before being released. Representative yeast colonies were isolated and purified. Based on morphological and physiological characteristics, representative yeast strains were chosen. A polymerase chain reaction (PCR) was performed according to methods described for the amplification of 26S rDNA D1/D2 domains. The amplified DNA was purified and sequenced. The average cell count in unripened honey was 8.4x103 CFU mL-1, in ripened honey was 6.0x102 CFU mL-1 and in stored pollen samples was 6.0x103 CFU g-1. The cell count in unripened honey was the highest in all collections. Twenty eight yeast species and 14 genera were identified associated with M. quinquefasciata. Species belonging to Starmerella clade represented 54.5% of total amount of isolates. Most of the described species in Starmerella clade are known to be associated with bees or related habitats. The prevalent species was Starmerella sp., a new yeast species. Some yeast isolates, phylogeneticly related to Candida haemulonii, Candida ranongensis and Sympodiomycopsis kandeliae are possibly new species. The abundance of yeasts and richness decrease along honey maturation process. Among the identified species, Cryptococcus spp. and Rhodotorula spp. were prevalent in the phylloplane of both leaves and flowers, and may represent a transient mycota vectored by bees. Zygosaccharomyces mellis might act as an agent of honey spoilage for bees. This study contributes to the knowledge of yeast community harbored by stingless bees, which seems to be specific for each bee species and for that, to discover new yeast species living on specific substrates such honey and pollen provisions.

Palavras-chave:  Stingless bees, Yeast, Honey, Pollen, Candida