Soil microbial community structure dynamics shape the rhizosphere priming effect patterns in the paddy soil

Area of Science:

• Soil Science
• Microbiology
• Ecology

Background:

• Soil organic carbon (SOC) decomposition and rhizosphere priming effects (RPEs) are influenced by microbial communities.
• Understanding how bacterial community structure regulates RPEs and responds to plant growth is crucial.

Purpose of the Study:

• To investigate RPE response to maize growth and nitrogen addition.
• To explore the role of bacterial community structure and keystone taxa in regulating RPEs.

Main Methods:

• Utilized the 13C natural abundance method in a C3 soil-C4 plant (maize) system.
• Employed 16S rRNA sequencing to analyze bacterial community structure.
• Constructed networks to identify keystone taxa and their correlation with C decomposition.

Main Results:

• RPEs shifted from negative to positive during maize growth (Day 30 to Day 75).
• Bacterial community structure shifted from r-strategists to K-strategists, influenced by C:N stoichiometry and soil pH.
• Distinct keystone taxa (e.g., Caulobacteraceae, Bacillus, Gemmatimonas) were identified at different growth stages and linked to RPE patterns.

Conclusions:

• Bacterial community structure and keystone taxa dynamics are key regulators of RPE variation during plant growth.
• Nitrogen addition and plant development significantly impact microbial community structure and function.
• This study offers insights into microbial mechanisms governing soil carbon cycling and RPEs.