Bacillus spp. isolated from pepper leaves and their function and inhibition of the fungal plant pathogen Colletotrichum scovillei

Abstract

Background Pepper is a popular ingredient in many Chinese households; however, anthracnose caused by Colletotrichum spp. has greatly decreased pepper production. The genus Bacillus is widely known for its important role in the development and protection of plants from phytopathogenic fungi. Results Fifty-eight endophytic strains were isolated from pepper leaves and tested for antifungal activity in this study. Specifically, L1-7 and L3-5 displayed growth inhibition rates of 79 and 80% against C. scovillei mycelium, respectively, while 25 of these strains all had growth inhibition rates of greater than 60%. Bacillus amyloliquefaciens and B. velezensis, based on culture and morphological identification with 16S rDNA and gyrB gene sequence analyses, were determined to be the respective species L1-7 and L3-5. Additionally, it was discovered that these two antagonistic endophytic bacteria could fix nitrogen, produce indoleacetic acid (IAA) and have a high salt tolerance. Pot experiments again showed excellent control of the pathogen C. scovillei by L1-7 and L3-5, with 80.64 and 73.39% control, respectively. Therefore, B. amyloliquefaciens (L1-7) and B. velezensis (L3-5) can be applied as biological control agents to protect peppers against C. scovillei-caused anthracnose. Conclusion Bacillus amyloliquefaciens (L1-7) and B. velezensis (L3-5) can be applied as biological control agents to protect peppers against C. scovillei-caused anthracnose. Thus, they can serve as promising biocontrol agents and plant growth promoters, and future research on the pertinent bacteria will serve as a useful guide for the creation of microbial resources.

Isolation of bacteria displaying potent antagonistic activity against fungi causes anthracnose disease in chili

“…(Table 4). For example, Bacillus amyloliquefaciens and B. velezensis isolated from pepper leaves displayed growth inhibition rates of 79 and 80% against C. scovillei mycelium (Wei et al 2023). According to Kwon et al (2022), B. tequilensis GYUN-300 was used for antagonization of the chili anthracnose fungus caused by C. acutatum in Korea.…”

“…Biological control of chili anthracnose with antagonistic organisms offers an effective method of managing pathogens in chili crop. Several reports show that bateria was already used as an anthrace pathogen for fungal antagonism caused by Colletotrichum spp., for instances, Bacillus amyloliquefaciens and B. velezensis inhibition C. scovillei (Wei et al 2023) (Kim et al 2016). In vitro research has proven that exposure of certain phytopathogenic fungi to antibiotics and fungal hydrolyzing enzymes such as chitinases, proteases, cellulases, or glucanases, peroxidase, and phenylalanine ammonia lyase can inhibit the fungal pathogens by degrading most fungal cell walls (Gomaa 2012).…”