Reduced chemodiversity suppresses rhizosphere microbiome functioning in the mono-cropped agroecosystems

Area of Science:

• Soil Science
• Microbiology
• Plant Science

Background:

• Rhizodeposits are crucial for soil health, regulating plant-microbe interactions and nutrient cycling.
• The impact of altered belowground carbon allocation and rhizodeposit chemodiversity on rhizosphere microbiome functioning remains poorly understood.

Purpose of the Study:

• To investigate the relationship between rhizosphere carbon allocation, rhizodeposit chemodiversity, and microbiome biodiversity and functioning in peanut (Arachis hypogaea) continuous mono-cropping systems.
• To elucidate the mechanisms driving rhizosphere microbiome changes under long-term mono-cropping.

Main Methods:

• Utilized ¹³CO₂ labeling to trace carbon allocation in peanut plants.
• Analyzed rhizodeposit chemodiversity and composition using metabolomics.
• Assessed rhizosphere microbiome composition and diversity via amplicon and shotgun metagenomic sequencing coupled with DNA stable-isotope probing (DNA-SIP).

Main Results:

• Continuous mono-cropping led to decreased rhizosphere carbon allocation, rhizodeposit chemodiversity, and microbial biodiversity.
• Plant-beneficial microbial taxa and key functional gene pathways declined with increasing years of mono-cropping.
• Rhizodeposit characteristics and microbial communities were significantly correlated, influenced by deterministic and stochastic ecological processes, respectively.

Conclusions:

• Reduced carbon deposition and rhizodeposit chemodiversity under peanut mono-cropping suppress rhizosphere microbial biodiversity and function.
• This study provides mechanistic insights into rhizosphere microbiome malfunctioning in mono-cropped systems.
• Findings offer guidance for future research aimed at improving soil ecosystem functioning through microbiome management.