The antagonistic mechanism of Bacillus velezensis ZW10 against rice blast disease: Evaluation of ZW10 as a potential biopesticide

Abstract

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the three major diseases affecting rice production and quality; it reduces rice grain yield by nearly 30%. In the early stage of this study, a strain of Bacillus velezensis with strong inhibition of M. oryzae was isolated and named ZW10. In vitro assays indicated prolonged germination time of conidia of M. oryzae treated with the antifungal substances of ZW10, 78% of the conidia could not form appressorium, and the conidial tubes expanded to form vacuolar structure and then shrank. The results of FDA-PI composite dyes showed that the antifungal substances of ZW10 inhibited the normal activity of M. oryzae hyphae that were rarely able to infect the epidermal cells of rice leaf sheath in vivo tests. In addition, rice treated with the antifungal substances of ZW10 showed a variety of defense responses, including activation of defense-related enzymes, increased expression of the salicylic acid pathway genes, and accumulation of hydrogen peroxide (H2O2), which might function directly or indirectly in resistance to pathogen attack. The field experiment with rice blast infection in different periods showed that the antifungal substances of ZW10 had the same control effect as carbendazim. The significant biological control activity of ZW10 and its capacity to stimulate host defenses suggest that this B. velezensis strain has the potential to be developed into a biopesticide for the biocontrol of rice blast.

Characterization of a Bacillus velezensis strain isolated from Bolbostemmatis Rhizoma displaying strong antagonistic activities against a variety of rice pathogens

“…Although the antagonistic efficacies between the different biocontrol agents were not compliant to be quantitively compared when the individual tests were not conducted on the same conditions, from the comparative literature analysis, we might still evaluate B. velezensis BR-01 to have the potential being a strong and broad-spectrum biocontrol agent in rice disease control. Currently, there have been numerous reports about the antagonistic effects and biocontrol efficacies of B. velezensis strains on M. oryzae, some of which were registered as the bacterial pesticides used in rice production (Chen et al, 2021). From our dual culture tests, B. velezensis BR-01 has an 83.7% relative inhibition rate on M. oryzae, which is comparable to most of other B. velezensis strains on M. oryzae (Sha et al, 2020;Chakraborty et al, 2021).…”

“…Currently, there have been numerous reports about the antagonistic effects and biocontrol efficacies of B. velezensis strains on M . oryzae , some of which were registered as the bacterial pesticides used in rice production ( Chen et al, 2021 ). From our dual culture tests, B. velezensis BR-01 has an 83.7% relative inhibition rate on M .…”

“…B. velezensis JK23, a radiationresistant strain isolated from radioactive contaminated soil, had strong inhibition against F. moniliforme (Zhang et al, 2021). B. velezensis ZW10, isolated from Sichuan basin neutral purplish soil, was reported to have strong antagonistic on M. oryzae growth on plate and the capacity to stimulate rice defenses (Chen et al, 2021). B. velezensis J17-4, isolated from healthy and sterilized stems of rice stem, could significantly inhibit the growth of Dickeya zeae and could significantly reduce the inhibitory effect of D. zeae strain EC1 against rice seed germination under laboratory inoculation conditions (Shi et al, 2022).…”

Biological Control of Plant Pathogens: A Global Perspective

“…In a semi-commercial large-scale study, the efficacy of these strains was found to be comparable to that of two commercial BCAs, but slightly lower than that of a commercial synthetic fungicides [ 47 , 59 ]. The considerable biological control activity of a Bacillus velezensis strain named ZW10, as well as its ability to boost host defenses, make it a potential biopesticide for rice blast biocontrol caused by the fungus Magnaporthe oryzae [ 60 ]. The commercially available B. amyloliquefaciens FZB42 product has considerably decreased lettuce bottom rot caused by R. solani .…”

Overview of biofertilizers in crop production and stress management for sustainable agriculture

“…Streptomyces hydrogenans metabolites can be used as safe biocontrol agents against Meloidogyne incognita and plant growth promoters for Solanum lycopersicum (Sharma et al, 2020 ). Bacillus velezensis is a potential pesticide due to its strong biocontrol activity and ability to strengthen host defense against Magnaporthe oryzae fungi, which cause rice blast disease in plants (Chen et al, 2021 ). An isolate of Trichoderma asperellum increased the resistance in tomato seedling to the disease A. alternata leaf spot (Yu et al, 2021 ).…”