Relative and Quantitative Rhizosphere Microbiome Profiling Results in Distinct Abundance Patterns

Area of Science:

• Microbiology
• Plant Science
• Environmental Science

Background:

• Next-generation sequencing (NGS) is widely used for microbiome characterization but typically yields relative abundance data.
• Relative abundance profiles may not accurately reflect the true microbial abundance in environmental samples.
• Understanding the quantitative dynamics of rhizosphere microbiomes is crucial for plant health and soil ecology.

Purpose of the Study:

• To compare relative and absolute abundance profiling of wheat rhizosphere microbiomes.
• To investigate the impact of soil water stress history on microbial community structure.
• To assess the correlation between microbial abundance and rhizosphere functional processes.

Main Methods:

• Combined 16S rRNA gene (bacteria) and ITS region (fungi) amplicon sequencing with real-time quantitative PCR (qPCR).
• Characterized the rhizosphere microbiome of wheat under varying soil water stress conditions.
• Analyzed both relative and estimated absolute abundances of microbial taxa.

Main Results:

• Changes in relative abundance of microbial phyla did not consistently match estimated absolute abundance patterns.
• Bacterial phyla in non-stressed soil showed enrichment in absolute abundance, contrasting with relative abundance data.
• Fungal groups (excluding Basidiomycota) showed largely unchanged absolute abundance regardless of water stress history.

Conclusions:

• Estimated absolute abundance provides a more realistic perspective of rhizosphere microbiome composition than relative abundance.
• Absolute quantification offers complementary insights into microbial community dynamics and ecological functions.
• This approach improves the understanding of plant-microbe interactions in the rhizosphere.