Genetic and functional characterization of a Bacillus sp. strain excreting surfactin and antifungal metabolites partially identified as iturin-like compounds

Abstract

Aims: A bacterial strain producing antifungal compounds active against the plant pathogenic fungi Fusarium, Rhizoctonia and Sclerotinia has been characterized and shown to control Rhizoctonia root rot of soya bean. Methods and Results: The metabolites excreted by Bacillus BNM 122 remained active after autoclaving, were resistant over a wide pH range and to hydrolytic enzymes. By 1 H-NMR and thin-layer chromatography analyses surfactin and iturin-like compounds were partially identified. Moreover, soya bean seeds bacterization with BNM 122 in a compost-based formulation was as effective controlling Rhizoctonia solani as pentachloronitrobenzene. According to its 16S rDNA sequence BNM 122 was closely related to Bacillus amyloliquefaciens and Bacillus subtilis. PCR analysis of the 16S-23S rRNA intergenic spacer region and repetitive sequence-based PCR (rep-PCR) genomic fingerprinting revealed a close genetic relationship to B. amyloliquefaciens. However, by physiological characterization using API tests, this strain resembled more B. subtilis. Conclusions: This is the first report describing the co-production of surfactin and iturin-like compounds by a putative strain of B. amyloliquefaciens. The synergistic effect of both lipopetides is a remarkable trait for a candidate biocontrol agent. Significance and Impact of the Study: This kind of research has relevance in order to minimize the use of synthetic fungicides and surfactants, contributing to the preservation of the environment.

Isolation, screening and growth optimization of antagonistic Bacillus subtilis MS21 from Thengapattanam estuary against plant fungal pathogens

“…alone (kumari et al, 2017). Many B. subtilis strains have been reported for their effective biocontrol activity by producing antifungal compounds (Silo-Suh et al, 1994;Souto et al, 2004;Cazorla et al, 2007;Islam et al, 2012 andMardanova et al, 2017).…”

Purification and partial characterization of an antimicrobial peptide produced by Bacillus sp. strain P45, a bacterium from the Amazon basin fish Piaractus mesopotamicus

“…Interestingly, Bacillus sp. BNM 122 was characterized as a strain secreting surfactin-like and iturin-like compounds (Souto et al, 2004), which are antimicrobial lipopeptides produced by B. subtilis and Bacillus amyloliquefaciens, respectively (Stein, 2005;Yu et al, 2002).…”

AISLAMIENTO E IDENTIFICACIÓN DE BACILLUS subtilis Y EVALUACIÓN DEL ANTAGONISMO IN VITRO FRENTE HONGOS FITOPATÓGENOS

“…Varios autores han informado la actividad antagónica del género Bacillus contra diferentes hongos fitopatógenos (Reinoso Pozo et al, 2007), lo que se atribuye a la producción de compuestos de naturaleza peptídica y lipopeptídica como las micobacilinas, iturinas, bacilomicinas, fungistatinas y micosubtilinas (Souto et al, 2004); compuestos que han demostrado ser efectivos en suprimir el crecimiento de patógenos in vitro o in situ (Badía et al, 2011;Sosa et al, 2005;Corrales et al, 2011). Entre los mecanismos de acción implicados en el control biológico están el parasitismo directo y muerte del patógeno, competencia por nutrientes, inducción de resistencia sistémica en la planta, disminuyendo el efecto dañino de los fitopatógenos (Orietta & Larrea, 2001).…”