Biological Control of Fusarium Stalk Rot of Maize Using Bacillus spp.

Abstract

Maize (Zea mays L.) is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08) were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

Biological Control of Fusarium oxysporum, the Causal Agent of Fusarium Basal Rot in Onion by Bacillus spp.

“…However, excessive and repeated use of chemical pesticides in agriculture have led to environmental pollution, reducing biodiversity, increased development of resistant pests and pathogens, and toxicity in animals including humans (Hassaan and El Nemr, 2020;Mesnage et al, 2014). The adoption of biological control is an important technique to reduce chemical pesticides, and genus Bacillus is among the most exploited microbial groups due to its high abundance, diversity, survival ability, and production of various bioactive compounds with direct and indirect antagonistic effects (Caulier et al, 2018;Han et al, 2015a;Saxena et al, 2020). Currently, several commercial Bacillus-based biological control agents are used in agriculture, including Bacillus amyloliquefaciens, Bacillus subtilis, B. thuringiensis, and Bacillus velezensis (Fira et al, 2018).…”