BLB8, an antiviral protein from Brevibacillus laterosporus strain B8, inhibits Tobacco mosaic virus infection by triggering immune response in tobacco

Abstract

BACKGROUND Tobacco mosaic virus (TMV) is one of destructive plant viruses, causing serious economic losses in the world. Using antiviral proteins or elicitors to inhibit viral infection or promote plant immunity is one of the efficient strategies against TMV. Our previous study identified that the fermentation broth of Brevibacillus laterosporus strain B8 showed strong antiviral activity against TMV. However, the active antiviral ingredient is still unclear. RESULTS Here, BLB8 (B. laterosporus strain B8 protein, BLB8), an antiviral protein from B. laterosporus strain B8 was isolated and characterized. BLB8 showed protective, inactive and curative effects against TMV, and the inhibition rate reached up to 63%, 83% and 55%, respectively. BLB8 infiltrated around the infection site of the recombinant virus TMV‐GFP inhibited the systemic extend and movement of TMV. Pretreatment of the bottom leaves with BLB8 inhibited the spread and accumulation of TMV in upper systemic leaves. Furthermore, BLB8 caused hypersensitive response (HR) in a dose‐dependent way, promoted H2O2 accumulation, and induced the expression of defense‐relative genes in Nicotiana benthamiana. CONCLUSION The antiviral protein BLB8 from B. laterosporus strain B8 effectively inhibits TMV infection in inactivation, protective and curative effects through triggering plant immunity in tobacco. Therefore, the present study provides a new antiviral agent for prevention and control of viral disease. © 2021 Society of Chemical Industry.

Leaf Bacteriome in Sugar Beet Shows Differential Response against Beet curly top virus during Resistant and Susceptible Interactions

“…The role of Brevibacillus in host plant resistance against viral pathogen has been reported in earlier studies. The antiviral protein BLB8 derived from the Brevibacillus laterosporus Laubach strain B8, when co-inoculated, effectively, reduced TMV infection through its direct antiviral properties, along with modulating the expression of host defense-related genes [ 27 ]. Tobacco leaf infiltration with pure BLB8 protein, in the absence of the virus, elicited a hypersensitive response (HR) through the production of H 2 O 2 in a dose-dependent manner.…”

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