Control Efficacy of Bacillus velezensis AFB2-2 against Potato Late Blight Caused by Phytophthora infestans in Organic Potato Cultivation

Abstract

Although late blight is an important disease in eco-friendly potato cultivation in Korea, it is highly dependent on the use of eco-friendly agricultural materials and the development of biological control technology is low. It is a necessary to develop an effective biocontrol agent to inactivate late blight in the field. AFB2-2 strain is a gram-positive with peritrichous flagella. It can utilize 20 types of carbon sources, like L-arabinose, and D-trehalose at 35°C. The optimal growth temperature of the strain is 37°C. It can survive at 20-50°C in tryptic soy broth. The maximum salt concentration tolerated by AFB2-2 strain is 7.5% NaCl. AFB2-2 strain inhibited the mycelial growth of seven plant pathogens by an average inhibitory zone of 10.2 mm or more. Among the concentrations of AFB2-2, 107 cfu/ml showed the highest control value of 85.7% in the greenhouse. Among the three concentrations of AFB2-2, the disease incidence and severity of potato late blight at 107 cfu/ml was lowest at 0.07 and 6.7, respectively. The nucleotide sequences of AFB2-2 strain were searched in the NCBI GenBank; Bacillus siamensis strain KCTC 13613, Bacillus velezensis strain CR-502, and Bacillus amyloliquefaciens strain DSM7 were found to have a genetic similarity of 99.7%, 99.7%, and 99.5%, respectively. The AFB2-2 strain was found to harbor the biosynthetic genes for bacillomycin D, iturin, and surfactin. Obtained data recommended that the B. velezensis AFB2-2 strain could be considered as a promising biocontrol agent for P. infestans in the field.

Isolation and Screening of Antagonistic Endophytes against Phytophthora infestans and Preliminary Exploration on Anti-oomycete Mechanism of Bacillus velezensis 6-5

“…Endophytes 6-5 were speculated as B. velezensis , a Gram-positive bacterium with strong stress tolerance. B. velezensis has been reported to exhibit antagonistic activity against a wide range of phytopathogens, considered one of the most common biocontrol bacteria [ 39 , 40 , 41 , 42 ]. For example, B. velezensis OEE1, isolated from root tissues of olive trees, can significantly suppress Verticillium wilt of olive [ 43 ].…”

A New Biocontrol Tool to Fight Potato Late Blight Based on Willaertia magna C2c Maky Lysate

“…Fungicidal activity was also observed with ethyl-acetate extracts from strains belonging to the fungal genus Chaetomium [ 25 ]. Living microorganisms, such as bacterial strains of Streptomyces , Pseudomonas , Saccharothrix, Bacillus , and Nocardiopsis , are also able to act as biological control agents against PLB [ 26 , 27 , 28 , 29 ]. However, these molecules and strains have not been tested under field conditions.…”

Complete Genome Sequence of Antibiotic-Producing Bacillus velezensis H208, Isolated from Ginger Rhizosphere in Laifeng County, China

“… Bacillus velezensis was reported as an antagonistic bacterium against various plant diseases ( 1 , 2 ) and also promotes plant growth ( 3 , 4 ). It produces multiple antimicrobial secondary metabolites, including antifungal peptides ( 5 ), ketone metabolites, and volatile organic compounds ( 6 ).…”