Yeast Microbiome of Avicennia officinalis: Differences in Its Taxonomic and Functional Composition Within Plant Compartments

Mangrove ecosystems are renowned for their rich fungal diversity, housing a plethora of multicellular fungi and yeasts. In this investigation, we examined the yeast diversity associated with various compartments (rhizospheric soil, stems, roots, leaves, barks, and flowers) of the widely distributed mangrove tree, <i>Avicennia officinalis</i>, from the Kumbalam and Puthuvype mangroves in central Kerala, India. Our study revealed that the yeast strains were not uniformly distributed in various compartments. The highest abundance of yeasts was found in leaves (42%), followed by sediment (21%), and the lowest in flowers (5%). Among the 45 isolates, 27% comprised red yeasts. Dominant genera included <i>Rhodotorula</i> (27.5%), <i>Debaryomyces</i> (17.6%), <i>Kluyveromyces</i> (5.9%), <i>Cryptococcus</i> (9.8%), and <i>Candida</i> (7.8%), while genera such as <i>Geotrichum</i>, <i>Lodderomyces</i>, <i>Ogataea</i>, <i>Galactomyces</i>, and <i>Saitozyma</i> were represented by single isolates. Certain yeast species, such as <i>C. tropicalis</i> and <i>Rhodotorula paludegina</i>, exhibited a cosmopolitan distribution in various plant compartments of <i>A. officinalis</i>. An analysis of the proximate composition of different plant compartments of <i>A. officinalis</i> revealed variations in C, N, S, H, Ca, K, and the C/N ratio. Interestingly, these variations were positively correlated with the yeast community composition, suggesting a potential role of the elemental composition of plants in shaping the yeast biome of <i>A. officinalis</i>. However, our understanding of the inter-relationships among yeast communities in different plant compartments remains limited, highlighting the need for further comprehensive investigations in this field.