Potential of an endophytic bacteria Bacillus amyloliquefaciens 3–5 as biocontrol agent against potato scab. (February 2022) - Cui, Lingxiao
Abstract: To obtain a potential biocontrol agent for potato scab, 75 endophytic bacteria were isolated from the healthy potato tubers and strain 3-5 was selected as an optimal antagonistic bacterium against Streptomyces griseoplanus ( Streptacidiphilus griseoplanus ) causing potato scab. Strain 3-5 was identified as Bacillus amyloliquefaciens based on its morphological characteristics, 16S rDNA and gyrB gene sequence analysis. B. amyloliquefaciens 3–5 has biological functions of indole-3-acetic acid (IAA) production and nitrogen fixation. Polymerase chain reaction (PCR) detection revealed that B. amyloliquefaciens 3–5 had 6 diverse antibacterial substance synthesis genes, named bacD, bacAB, ituD, ituC, sfP and albF, which resulted in the production of bacilysin, iturin, surfactin and subtilosin. Field efficacy evaluation revealed that B. amyloliquefaciens 3–5 (solid fermentation) was successful in controlling potato scab with a 38.90 ± 3.2140% efficiency which is higher than other chemical bactericides except zhongshengmycin·oligosaccharins and kasugamycin·zhongshengmycin. The endophytic bacterium B. amyloliquefaciens 3–5 could be used as a biocontrol agent against potato scab due its control efficacy and environmental safety. Highlights: Strains 3–5, one of 75 potato endophytes, was identified as Bacillus amyloliquefaciens. It has the ability of IAA production and nitrogen fixation. 6 diverse antibacterial substance synthesis genes from Bacillus amyloliquefaciens 3–5 appear positive. It exhibits biocontrol activity against potato scab under the field. It could be a multifunctional biocontrol agent used to control potato diseases.