Drought and host selection influence bacterial community dynamics in the grass root microbiome

Area of Science:

• Microbial Ecology
• Plant Science
• Genomics

Background:

• Root endophytes influence plant health during drought.
• The impact of drought on root endosphere bacteria is poorly understood.

Purpose of the Study:

• To characterize bacterial communities in drought-stressed root and rhizosphere tissues of diverse Poaceae species.
• To investigate the effect of drought on the correlation between host phylogeny and root microbiome composition.

Main Methods:

• 16S rRNA gene profiling of root and rhizosphere bacterial communities.
• Analysis across two watering regimes and two developmental time points in 18 Poaceae species.
• Phylogenetic analysis of host plants and their associated microbiomes.

Main Results:

• Drought weakens the correlation between host phylogeny and root microbiome dissimilarity.
• A conserved shift in bacterial community composition was observed under drought.
• Significant enrichment of Actinobacteria was detected within plant roots during drought, independent of soil conditions.

Conclusions:

• Drought induces conserved bacterial community shifts in plant roots, favoring Actinobacteria.
• The observed Actinobacteria enrichment is an absolute increase in abundance within the root endosphere.
• Understanding these drought-induced microbiome changes is crucial for plant stress adaptation and crop improvement.