Comparing methods for identifying Bacillus strains capable of producing the antifungal lipopeptide iturin A.
Lipopeptides represent a unique class of bioactive microbial secondary metabolites, and iturin A shows attractive antibiotic properties among them. This study compares three methods, such as yeast/fungal growth inhibition assay, quantitative high-performance liquid chromatography (HPLC) and polymerase chain reaction (PCR) for identifying a number of Bacillus species that produce iturin A. We examined the feasibility of screening iturin A-producing Bacillus strains by PCR using specific primers for ituD and lpa-14 amplification. Twenty standard strains and 120 field-collected Bacillus spp. isolates were tested in this study. Four B. subtilis and one B. circulan strains from ATCC, and B. amyloliquefaciens B128, a known iturin A producer, exhibited positive results. Of the 120 field-collected isolates, 42 strains were positive. The potential of producing iturin A by these PCR-positive strains were then confirmed by conventional methods such as fungal growth inhibition assay and HPLC analysis. The consistency between results of PCR, HPLC, and fungal growth inhibition assay suggests that the PCR method could be used as an alternative tool for fast screening of iturin A-producing Bacillus strains from the environment. This is the first report of detecting iturin A production from B. circulans.
Hsieh
Feng-Chia
FC
Biopesticides Division, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, 11 Kuang Ming Road, Wufeng, Taichung Hsien 413, Taiwan.
Lin
Tsung-Chun
TC
Meng
Menghsiao
M
Kao
Suey-Sheng
SS
D051080:Acyl-Carrier Protein S-Malonyltransferase / Q000235:genetics; D000935:Antifungal Agents / Q000302:isolation & purification / Q000378:metabolism*; D001407:Bacillus / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics; D008826:Microbial Sensitivity Tests / Q000379:methods; D010456:Peptides, Cyclic / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods*; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics
D000935:Antifungal Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010456:Peptides, Cyclic; C082662:phosphopantetheinyl transferase; C013579:iturin A; D051080:Acyl-Carrier Protein S-Malonyltransferase; D017855:Transferases (Other Substituted Phosphate Groups)