Isolation and characterization of siderophore producing antagonistic rhizobacteria against Rhizoctonia solani

Abstract

Plant protection through siderophore producing rhizobacteria (SPR) has emerged as a sustainable approach for crop health management. In present study, 220 bacteria isolated from tomato rhizosphere were screened for in vitro antagonistic activity against Rhizoctonia solani AG-4. Nine potent antagonistic strains viz., Alcaligenes sp. (MUN1, MB21, and MPF37), Enterobacter sp. (MPM1), Pseudomonas sp. (M10A and MB65), P. aeruginosa (MPF14 and MB123) and P. fluorescens (MPF47) were identified on the basis of physiological characters and 16S rDNA sequencing. These strains were able to produce hydrolytic enzymes, hydrogen cyanide, indole acetic acid, although, only few strains were able to solubilize phosphate. Two strains (MB123 and MPF47) showed significant disease reduction in glasshouse conditions were further evaluated under field conditions using three different application methods. Application of P. fluorescens (MPF47) in nursery as soil mix + seedling root treatments prior to transplantation resulted in significant disease reduction compared to control. Total chlorophyll and available iron were significantly higher in the MPF47 treated plants in contrast to infected control. In conclusion, siderophore producing bacteria MPF47 have strong biocontrol abilities and its application as soil mix + seedling root treatments provided strong shield to plant roots against R. solani and could be used for effective bio-management of pathogen.

Streptomyces globosus UAE1, a Potential Effective Biocontrol Agent for Black Scorch Disease in Date Palm Plantations

“…The identity of the BCA (isolate #7) was further confirmed by the ribosomal gene (16 S rRNA) sequence analysis, and the isolate revealed 100% sequence similarity with S. globosus (Krassilnikov, 1941) Waksman in Waksman and Lechevalier (1953) and Streptomyces toxytricini (Preobrazhenskaya and Sveshnikova, 1957; Pridham et al, 1958). The 16 S rRNA sequencing has been used as a basic approach for the identification of microbial communities as well as for assessing microbial diversity in natural environments (Solanki et al, 2014). Based on morphological, cultural and physiological characterizations, our results confirmed that the selected species was S. globosus (Strain UAE1).…”

Characterization of antagonistic‐potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato

“…Disease sick plots were artificially prepared by mixing actively grown wheat bran culture of R. solani in natural soil according to Solanki et al . . Seedlings were treated with antagonistic bacterial strains as described in pot experiment.…”

“…Field plots (3 Â 3 m 2 ) comprised five rows and five plants row À1 laid in a randomized block design with five treatments: T1-MB14 (10 À8 cfu ml À1 ), T2-MB101 (10 À8 cfu ml À1 ), T3-Carbendazim 50 wettable powder (0.1%), T4-healthy control (without pathogen and antagonist) and T5-R. solani infested control. Disease sick plots were artificially prepared by mixing actively grown wheat bran culture of R. solani in natural soil according to Solanki et al [2]. Seedlings were treated with antagonistic bacterial strains as described in pot experiment.…”

Virulence and molecular characterization of Costa Rican isolates of Rhizoctonia solani from common bean

“…Chemical and cultural control are the most common management techniques (Beebe et al, 1991;Godoy-Lutz et al, 1996a;Polanco et al, 1996), but during the last decades the biocontrol using different bacterial genus has been adopted as a sustainable approach for crop health management. However, they are not sufficient to avoid production losses (Solanki et al, 2013;Kanini et al, 2013).…”