Behind the nectar: the yeast community in bromeliads inflorescences after the exudate removal

Bromeliads are neotropical plants endowed with an extensive variety of floral structures, including inflorescences that combine elements of both leaves and flowers, making these organisms unique. However, studies that focus exclusively on yeast from the external surface of inflorescences as opposed to their exudates, such as nectar, are scarce. This study aimed to analyze the yeast community associated with bromeliad inflorescences after exudate removal with different types of predominant pollination syndrome, namely ornithophily (birds), and melittophily (bees) in the northeast Brazilian Atlantic Forests. Yeasts were isolated and identified by sequencing the D1/D2 domain of the nc 26S rDNA. We obtained 64 yeast isolates belonging to 27 species (67% Basidiomycota and 33% Ascomycota), of which six were possible new species. Papiliotrema flavescens , Candida intermedia , Aureobasidium thailandense , and Meyerozyma guilliermondii were the most frequent, with at least one of these species present in eight out of ten samples. Close to half of the yeast were singletons, and the highest richness was observed in ornithophilous bromeliads. The dissimilarity of yeast communities between different pollinator syndromes was greater than 85% ( p <0.05). As expected, traits such as flower length, nectar volume, and concentration were different between the syndromes. The results indicate a high diversity of described and undescribed yeast species associated with bromeliad inflorescences even after removal of the nectar, with prevalence of the phylum Basidiomycota. Graphical abstract