From Strain Characterization to Field Authorization: Highlights on Bacillus velezensis Strain B25 Beneficial Properties for Plants and Its Activities on Phytopathogenic Fungi

Abstract

Agriculture is in need of alternative products to conventional phytopharmaceutical treatments from chemical industry. One solution is the use of natural microorganisms with beneficial properties to ensure crop yields and plant health. In the present study, we focused our analyses on a bacterium referred as strain B25 and belonging to the species Bacillus velezensis (synonym B. amyloliquefaciens subsp. plantarum or B. methylotrophicus), a promising plant growth promoting rhizobacterium (PGPR) and an inhibitor of pathogenic fungi inducing crops diseases. B25 strain activities were investigated. Its genes are well preserved, with their majority being common with other Bacillus spp. strains and responsible for the biosynthesis of secondary metabolites known to be involved in biocontrol and plant growth-promoting activities. No antibiotic resistance genes were found in the B25 strain plasmid. In vitro and in planta tests were conducted to confirm these PGPR and biocontrol properties, showing its efficiency against 13 different pathogenic fungi through antibiosis mechanism. B25 strain also showed good capacities to quickly colonize its environment, to solubilize phosphorus and to produce siderophores and little amounts of auxin-type phytohormones (around 13,051 µg/mL after 32 h). All these findings combined to the fact that B25 demonstrated good properties for industrialization of the production and an environmental-friendly profile, led to its commercialization under market authorization since 2018 in several biostimulant preparations and opened its potential use as a biocontrol agent.

Comparative Genome Analysis Reveals Phylogenetic Identity of Bacillus velezensis HNA3 and Genomic Insights into Its Plant Growth Promotion and Biocontrol Effects

“…The existence of carbohydrate active enzymes in the genetic material of B. velezensis strains is significant in numerous ways, including the strain’s capacity to suppress the pathogen and its absorption of various nutrients ( 48 ). Enzymes of interest can also be isolated and used industrially ( 52 ).…”

Control of Fungal Diseases and Fruit Yield Improvement of Strawberry Using Bacillus velezensis CE 100

“…Bacillus spp. are a versatile group of PGPB that have exhibited strong biocontrol activity against various fungal, bacterial, and viral plant pathogens [41,42,[47][48][49]. Specifically, Bacillus spp.…”

“…These include M. phaseolina which causes charcoal rot, F. oxysporum f. sp. fragariae that cause fusarium wilt, and Botrytis cinerea, which causes grey mold in strawberries [6,9,41,42]. The biocontrol and bio-stimulation potential of Bacillus spp.…”

“…The biocontrol and bio-stimulation potential of Bacillus spp. are attributed to their functional properties, such as the production of antibiotics, lytic enzymes, IAA, ammonia-N, and phosphate solubilization [29,41,42].…”

Biocontrol activity and action mechanism of Bacillus velezensis strain SDTB038 against Fusarium crown and root rot of tomato

“…Fusarium crown and root rot of tomato are mainly controlled by biological control, which had proven the best method and received increasing attention from the agricultural industry in recent years. Plant growth-promoting rhizobacteria (PGPR) are bacteria that are good for crops and can stabilize the soil, promote plant growth and inhibit or reduce plant damage caused by disease (Joly et al, 2021). PGPR are considered promising biocontrol agents and utilize the plant rhizosphere and other areas as attachment points; these organisms have a control effect on pathogens, which could reduce the incidence of diseases (Riaz et al, 2021).…”