Physiological and morphological plasticity in response to nitrogen availability of a yeast widely distributed in the open ocean

• Published in: FEMS Microbiology Ecology
• Main Authors: Diver, P, Ward, BA, Cunliffe, M
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2024
• Subjects: functional traits; marine fungi; marine yeast; nitrogen; plankton ecology; Seawater; Nitrates; Atlantic Ocean; Yeasts; Ammonium Compounds; Urea; North Atlantic
• Online Access: https://pearl.plymouth.ac.uk/handle/10026.1/22489; https://doi.org/10.1093/femsec/fiae053

<jats:title>Abstract</jats:title> <jats:p>Yeasts are prevalent in the open ocean, yet we have limited understanding of their ecophysiological adaptations, including their response to nitrogen availability, which can have a major role in determining the ecological potential of other planktonic microbes. In this study, we characterised the nitrogen uptake capabilities and growth responses of marine-occurring yeasts. Yeast isolates from the North Atlantic Ocean were screened for growth on diverse nitrogen substrates, and across a concentration gradient of three environmentally relevant nitrogen substrates: nitrate, ammonium, and urea. Three strains grew with enriched nitrate while two did not, demonstrating that nitrate utilisation is present but not universal in marine yeasts, consistent with existing knowledge of non-marine yeast strains. Naganishia diffluens MBA_F0213 modified the key functional trait of cell size in response to nitrogen concentration, suggesting yeast cell morphology changes along chemical gradients in the marine environment. Meta-analysis of the reference DNA barcode in public databases revealed that the genus Naganishia has a global ocean distribution, strengthening the environmental applicability of the culture-based observations. This study provides novel quantitative understanding of the ecophysiological and morphological responses of marine-derived yeasts to variable nitrogen availability in vitro, providing insight into the functional ecology of yeasts within pelagic open ocean environments.</jats:p>