Seed‐borne endophytic Bacillus velezensis LHSB1 mediate the biocontrol of peanut stem rot caused by Sclerotium rolfsii

Abstract

Aims This study aimed to obtain an antagonistic endophyte against Sclerotium rolfsii from peanut seeds, evaluate the biocontrol efficacy towards peanut stem rot and explore its antifungal mechanism against S. rolfsii. Methods and Results Thirty‐seven endophytic bacteria were isolated from peanut seeds, six of which exhibited stronger antagonistic activities against S. rolfsii (inhibition rate, IR of hyphae growth ≥70%). Strain LHSB1, the strongest antagonistic strain, was identified as Bacillus velezensis. LHSB1 showed 93·8% of radial growth inhibition of S. rolfsii hyphae and exhibited obvious antagonistic activity against another six pathogenic fungi of peanut. Pot experiments showed two different LHSB1 treatments both significantly reduced the disease incidence and severity of stem rot (P < 0·05) compared to the controls, and the biocontrol efficacy reached 62·6–70·8%, significantly higher than that of Carbendazim control (P < 0·05). Further analyses revealed LHSB1 culture filtrate significantly inhibited sclerotia formation and germination, caused the abnormalities and membrane integrity damage of S. rolfsii hyphae, which might be the possible mode of action of LHSB1 against S. rolfsii. Three antifungal lipopeptides bacillomycin A, surfactin A and fengycin A, were detected in LHSB1 culture extracts by UPLC‐ESI‐MS, which could be responsible for the biocontrol activity of LHSB1 against S. rolfsii. Conclusion Our results suggested that the seed‐borne endophytic B. velezensis LHSB1 would be a tremendous potential agent for the biocontrol of peanut stem rot caused by S. rolfsii. Significance and Impact of the Study This comprehensive study provides a candidate endophytic biocontrol strain and reveals its antifungal mechanism against S. rolfsi. To the best of our knowledge, this is the first time that seed‐borne endophytic B. velezensis was used as the biocontrol agent to control peanut stem rot.

Crop Protection against Botrytis cinerea by Rhizhosphere Biological Control Agent Bacillus velezensis XT1

“…Antagonistic activity against the pathogens Monilinia fructicola [ 61 ] and B. cinerea (60%) reached maximum levels of > 80% and 60%, respectively, mainly due to the large amount of lipopeptides produced (10 g/L) [ 67 ]. Many studies of olive, tomato, corn, peanut, pepper, maize and rice crop yields have also described the biocontrol activity of B. velezensis strains against phytopathogens such as Verticillium dahliae , Fusarium graminerarum , Sclerotium rolfsii , Phytophthora and B. cinerea [ 68 , 69 , 70 , 71 , 72 , 73 , 74 ]. Our results are in line with the findings of Lee et al (2006) [ 75 ] who investigated the effect of radicular applications of B. subtilis WXCDD105 on B. cinerea in tomato plants.…”

Probiotic Endophytes for More Sustainable Banana Production

“…Many PGP endophytic microbes are widely accepted as biofertilizers, biostimulants, and biocontrol agents [ 11 , 13 , 49 ]. These microbes exert antagonistic effects by producing antibiotic compounds, lipopeptides, cell wall degrading enzymes, volatile compounds, hydrogen cyanide (HCN), and siderophores [ 50 , 51 , 52 , 53 ]. Some of these beneficial microbes aggregate the soil particles to improve the soil structure and secrete extracellular metabolites to augment the breakdown of complex organic material and insoluble nutrients into simple, more available forms [ 54 ].…”

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

“…Abo-Zaid et al [34] used a talc-based medium to ferment Streptomyces cellulosae Actino 48 with a high chitinase production which could effectively inhibit the mycelial growth of Sclerotium rolfsii. The rhizosphere growth-promoting bacteria Bacillus pumilus LX11 [14] and the seed endophytes Bacillus velezensis LHSB1 [35] can effectively antagonize Sclerotium rolfsii to signi cantly reduce the incidence of stem rot and can be used as potential biocontrol agents. The present research found that the high concentration fermentation solution of Novosphingobium panipatense, a dominant strain signi cantly enriched by calcium at the pod lling stage, could signi cantly inhibit the mycelial growth and nucleus formation of Sclerotium rolfsii.…”