Enhancing soil citrulline degrading function to mitigate soil-borne Fusarium wilt.

Area of Science:

• * Soil microbiology and plant pathology.
• * Molecular plant-microbe interactions.
• * Agricultural sustainability and biocontrol.

Background:

• * Continuous cropping intensifies soil-borne diseases like Fusarium wilt.
• * The interplay between plant metabolites, pathogens, and microbial functions in the rhizosphere is not well understood.
• * Citrulline accumulation is linked to increased Fusarium wilt severity.

Purpose of the Study:

• * To elucidate the role of citrulline in Fusarium wilt development under continuous cropping.
• * To identify microbial functions involved in citrulline metabolism in the rhizosphere.
• * To develop a biocontrol strategy targeting citrulline degradation.

Main Methods:

• * Correlation analysis between citrulline levels and disease severity.
• * Metagenomic sequencing to analyze microbial functions in different soil types.
• * Gene knockout experiments to identify key enzymes in citrulline degradation.
• * Inoculation experiments with engineered microbial consortia.

Main Results:

• * Citrulline accumulation positively correlates with Fusarium wilt severity by boosting pathogen fusaric acid production.
• * Citrulline turnover functions are reduced in soils prone to Fusarium wilt.
• * The gene arcB in Pseudomonas putida YDTA3 is crucial for citrulline degradation.
• * Inoculating an arcB-expressing Escherichia consortium (EO-arcB) mitigated Fusarium wilt in cucurbit crops.

Conclusions:

• * Soil citrulline metabolism significantly influences Fusarium wilt.
• * Enhancing soil citrulline-degrading functions offers a viable biocontrol strategy against Fusarium wilt.
• * This study provides insights into rhizosphere dynamics and promotes sustainable agriculture.