Yeast microbiome of Avicennia officinalis: Differences in its taxonomic and functional composition among the plant compartments

Introduction: Mangrove ecosystems are renowned for their rich fungal diversity, housing a plethora of multicellular fungi and yeasts.

Methods: 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, Avicennia officinalis, from the Kumbalam and Puthuvype mangroves.

Results: Our survey revealed a diverse distribution of yeast strains, with the highest abundance found in leaves (42%), followed by sediment (21%), and the lowest in flowers (5%). Among the 45 isolates identified, approximately 27% comprised red yeasts. Dominant genera included Rhodotorula (27.5%), Debaryomyces (17.6%), Kluyveromyces (5.9%), Cryptococcus (9.8%), and Candida (7.8%), while genera such as Geotrichum, Lodderomyces, Ogataea, Galactomyces, and Saitozyma were represented by single isolates. Certain yeast species, such as C. tropicalis and Rhodotorula paludegina, exhibited cosmopolitan distribution across various plant compartments of A. officinalis. Analysis of the proximate composition of different plant compartments of A. officinalis revealed variations in C, Na, and Ca content and in C/N and C/K ratios. 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 A. officinalis. Furthermore, we observed substantial variation in the hydrolytic potentials of yeast isolates from rhizospheric soil samples and plant compartments, indicating it to be a possible basis of this interaction.

Conclusion: 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.