Sphingomonas clade and functional distribution with simulated climate change

Area of Science:

• Microbial Ecology
• Environmental Microbiology
• Bacterial Adaptation

Background:

• Microbes are vital ecosystem components threatened by climate change and pollution.
• Understanding microbial responses to environmental shifts is critical for ecosystem health.
• Sphingomonas, a prevalent gram-negative bacteria, plays a key role in litter decomposition across diverse ecosystems.

Purpose of the Study:

• To investigate the climate response of the bacterial genus Sphingomonas.
• To determine if Sphingomonas clade and functional composition align with site-specific climate conditions.
• To assess Sphingomonas' response to climate change relative to native communities.

Main Methods:

• Conducted an 18-month microbial community reciprocal transplant experiment across a Southern California climate gradient.
• Extracted Sphingomonas sequences from metagenomic data.
• Assessed Sphingomonas clade and functional gene composition using bioinformatics and statistical analyses (PERMANOVA).

Main Results:

• Significant shifts in Sphingomonas clade and functional composition were observed after 18 months, correlating with site conditions (PERMANOVA; P < 0.001).
• Climate and substrate were identified as key drivers determining Sphingomonas composition.
• Transplanted Sphingomonas communities showed a directional shift towards the native composition of the grassland site.

Conclusions:

• Sphingomonas bacterial communities, encompassing both clade and functional diversity, are significantly influenced by climate and substrate.
• These findings support the hypothesis that microbial communities respond to climate change across different scales of genetic variation.
• Understanding these responses is essential for predicting microbial community dynamics and ecosystem functions under future climate scenarios.