Temperature-Dependent Biofilm Development in Antarctic Endophytic Microbial Communities

Abstract

Climate change is reshaping Antarctic ecosystems, where the resilience of Deschampsia antarctica and Colobanthus quitensis is mediated by endophytic microbial communities assembled under strong abiotic drivers. This study explores the temperature-dependent biofilm development in two Antarctic endophytic microbial communities (ALS and LS). Multivariate analysis revealed a fundamental trade-off between planktonic expansion and biofilm matrix investment as a function of thermal cues. While moderate warming (15–25 °C) optimized cell viability and turbidity, extreme thermal stress at 37–42 °C in nutrient-rich conditions triggered a significant shift toward a matrix-rich signature, characterized by a synergistic increase in total DNA and cellulose. Crucially, at the thermal extreme of 42 °C, we observed a decoupling of optical density from culturable biomass, where high turbidity did not translate into viable cells, signaling a state of severe environmental stress. These results identify 25 °C as the quantitative threshold for optimal growth, while temperatures of 37–42 °C act as a specific trigger for protective matrix production. Such thermal plasticity suggests that Antarctic endophytes are evolutionarily primed for persistence not only in cold native niches but also during bird-mediated dispersal at endothermic host temperatures.

Key findings

• ▸Moderate warming between 15–25°C optimizes cell viability and turbidity in Antarctic endophytic communities.
• ▸Extreme thermal stress at 37–42°C induces a significant shift toward matrix-rich biofilms characterized by increased total DNA and cellulose.
• ▸At 42°C, optical density decouples from culturable biomass, indicating that high turbidity does not reflect viable cell counts under severe environmental stress.

Keywords

Identifiers

DOI

10.3390/microorganisms14030580

Journal

Microorganisms

Year

2026