The Resistance of Peanut to Soil-Borne Pathogens Improved by Rhizosphere Probiotics Under Calcium Treatment

Abstract Background: Peanut (Arachis hypogaea L.) is an important oil and economic crop. Calcium can regulate plant autoimmunity, respond to biotic and abiotic stresses, and improve plant resistance to pathogens. The enrichment of beneficial microorganisms in the rhizosphere is related to plant disease resistance and soil development. The purpose was to analyze the differences of peanut rhizosphere microbial community structure between calcium treatment and control during two growth stages, and the reason that calcium application could improve peanut’s resistance to soil-borne pathogens.. Results: The 16S amplicon sequencing of rhizosphere microbiome showed that calcium application significantly enriched Serratia marcescens and other three dominant strains at the seedling stage. At the pod filling stage, ten dominant stains such as Sphingomonas changbaiensis and Novosphingobium panipatense were enriched by calcium. Serratia marcescens aseptic fermentation filtrate was mixed with PDA medium and inoculated with soil-borne pathogens, which could inhibit the growth of Fusarium solani and Aspergillus flavus at the seedling stage. The fermentation filtrate of Novosphingobium panipatense was mixed with PDA medium and inoculated with main pathogens, which could inhibit the growth of Sclerotium rolfsii and Leptosphaerulina arachidicola.Conclusions: Calcium application enhanced the ability of peanuts to resist pathogens by enriching specific dominant bacteria.