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.

Gene co-expression network analysis identifies hub genes associated with different tolerance under calcium deficiency in two peanut cultivars

“…Li et al found that both embryo and red skin of peanut seed need to absorb Ca 2+ that's excreted from the shell to ensure pod growth and development, and that peanut seed development was regulated by the collaboration of Ca 2+ signal transduction and hormone regulation pathway [8]. Zhang et al also found that calcium application could improve disease resistance to soil-borne pathogens by enriching them with speci c dominant bacteria [9]. Chen et al identi ed that multiple signal pathways involved in embryo abortion under calcium de ciency, which induced increased IAA and ethylene but decreased ABA, gibberellin, cytokinin and brassinosteroid levels [10].…”

“…Despite the global view of peanut transcriptome under calcium de ciency, previous studies only reported differentially expressed genes (DEGs) between calcium de cient and su cient conditions in the same cultivar [4,6,[8][9][10], and few of them made comparisons between different cultivars with different seed size, which showed tolerance inconsistency under calcium de ciency. The pod fullness was reported to be in uenced by seed calcium concentration, which is affected by seed size, absorption ability of cultivars and soil calcium fertility during seed development stage [16].…”