Antimicrobial Activity of Culture Filtrate of Bacillus amyloliquefaciens RC-2 Isolated from Mulberry Leaves

Abstract

A potential antagonist, Bacillus amyloliquefaciens strain RC-2, against Colletotrichum dematium, mulberry anthracnose fungus, was obtained from healthy mulberry leaves by in vitro and in vivo screening techniques. Application of culture filtrate of RC-2 inhibited disease on mulberry leaves, indicating that suppression was due to antifungal compounds in the filtrate. Development of mulberry anthracnose on mulberry leaves was inhibited only when the culture filtrate was applied before fungal inoculation, and it was not inhibited by application after inoculation. These results suggest that the antifungal compounds in the filtrate exhibit a preventive effect on the disease. Peptone significantly increased production of the antifungal compounds. The culture filtrate of RC-2 also inhibited the growth of several other phytopathogenic fungi and bacteria, such as Rosellinia necatrix, Pyricularia oryzae, Agrobacterium tumefaciens, and Xanthomonas campestris pv. campestris, in vitro. From the culture filtrate of RC-2, seven kinds of antifungal compounds were isolated by high performance liquid chromatography analysis, and one of the compounds was determined as iturin A2, a cyclic peptide, by nuclear magnetic resonance and fast atom bombardment mass analysis.

Isolation and characterization of endophytic bacteria fromPlectranthus tenuiflorusmedicinal plant in Saudi Arabia desert and their antimicrobial activities

“…The bacterial strain was inoculated into medium A broth (100 mL) in a 250-mL Erlenmeyer flask and incubated in a rotary shaker (150 rpm) at 30 o C for 48 h. Cell-free supernatant was obtained by centrifugation (10,000 )g, 15 min) and filtered on a 0.45 lm Millipore filter. The antimicrobial activity of the culture filtrate was detected by the method of stainless steel cylinders (Yoshida et al 2001). The suspension of each indicator strain (0.5 mL) was mixed with 10 mL of suitable agar media at 558C, and the mixture was immediately poured in a 9 cm diameter petri dish.…”

In vitro effect of Bacillus thuringiensis strains and Cry proteins in phytopathogenic fungi of paddy rice-field

“…A paper by Oshida et al (28) showed that Bacillus amyloliquefaciens RC-2 filtrate culture has inhibited the growth of the Colletotrichum dematium (Persoon: Fries) fungus, besides other phytopathogens and bacteria, such as Rosellinia mecatrix, P. oryzae, Agrobacterium tumefaciens and Xanthomonas campestris pv. campestris.…”

Screening for antimicrobial activity among bacteria isolated from the Amazon Basin

“…Bacteriocin-like substances have been related to Bacillus spp. isolated from soil (4,18) and vegetal tissues (2,27). Isocoumarin antibiotics are produced by Bacillus spp., as demonstrated for B. subtilis strains from different habitats and geographic origins (19).…”