Yeasts associated with flowers and fruits from a semi-arid region of northeastern Brazil

Yeast species on flowers and fruits from 4 trees (cashew, Anacardium occidentalis; caja, Spondia lutea; urnbu, Spondia sp.; and mango, Mangifera indica) of the Northeastern region of Brazil were studied in field and market samples. Vigorous shaking removed most yeasts from fruit surfaces, and blending suspended and disaggregated the more firmly attached ones. Ripe fruits were dissected asseptically to separate the surface and internal communities. Isolations were made on Glucose-Yeast Extract-Peptone medium and Vitamin Free Yeast Base, both adjusted to pH 3.7 and containing 200 mg/l of chloramphenicol. The yeast communities of flowers and green fruits were dominated by basidiomycetous anamorphs (especially Cryptococcus laurentii). and black yeasts, but there was a sucession on ripe fruits to a community dominated by diverse ascomycctous species and their anamorphs. Metschnikowia pulcherrima was frequently isolated from cashew flowers and associated bees and a Candida entomaea -like species was prevalent on Caja fruits in the field. The ascomycetous yeast community of ripe fruits consisted preferentially of fermentative species with low physiological profiles, including Issatchenkia orientalis and Kloeckera javanica as frequent isolates. A sequence of samples from different stages of flowering and fructification, vigorous pre-isolation treatments and different isolation media should be used to obtain an adequate description of these yeast communities.