Biocontrol activities of bacteria from cowdung against the rice sheath blight pathogen

Abstract

To discover bacteria with potential biocontrol activity against the rice sheath blight (RSB) pathogen, Rhizoctonia solani, cowdung (CD) associated bacteria were screened for antifungal activity a dual-culture method. Five potential biocontrol bacteria were identified to species-level based on their colony morphology, physiology, biochemical characteristics, utilization of carbon sources, micromorphology and 16S rRNA sequences. The ability of two selected strains to inhibit RSB was evaluated in vivo and in vitro. The median effective concentration (EC 50 ) of crude extract from Streptomyces cochorusii strain NF0919 (NF0919) culture filtrate was 1.3 lg ml -1 , lower than the EC 50 of Jinggangmycin (a commercial antifungal agent widely used in China). At a concentration of 25.0 lg ml -1 , the crude extract completely inhibited mycelial growth of R. solani. The field biocontrol efficacy after spraying 7 days in 2013 and in 2014 was 78.4 and 98.1% with crude extract from NF0919 culture filtrate and 71.1 and 94.2% with fresh cells of Bacillus amyloliquefaciens strain SB177 (SB177). Results from the 2-year field experiment suggested that the crude extract from NF0919 culture filtrate or fresh cells of SB177 provided better disease control than other fungicides (Jinggangmycin and/ or Kresoxim-methyl). S. cochorusii strain NF0919 and B. amyloliquefaciens strain SB177 have good potential for field application and commercial use against the RSB pathogen.

Bacillus atrophaeus HAB-5 secretion metabolites preventing occurrence of systemic diseases in tobacco plant

“…As previously reported, except for root drenching, foliar application is one of the efficient methods for foliar disease control. Studies have focused on harvesting these compounds from the culture suspension, culture supernatant and crude extract sprayed on plants for disease control (Lo et al 1997;Ji et al 2013;Yang et al 2017). The present study provides evidence that crude extract metabolites of efficacy from the PGPR strain HAB-5 in reducing the virulence of TMV on tobacco plant.…”

“…The foliar spray treatment of Streptomyces spp. was reported efficiently to control rice sheath blight pathogen (Yang et al 2017). The crude extract metabolites from different strains of B. amyloliquefaciens were capable of reducing the severity of different diseases on plant (Ji et al 2013).…”

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“…These NILs allowed for the discovery of new resistance genes, namely, Pi1, Pi2 (=Piz5), Pi3, and Pi4b (Yu et al, 1991;Mackill and Bonman, 1992;Inukai et al, 1994). [75][76][77][78][79][80] Some upland cultivars such as the traditional African cultivars Moroberekan and OS6 have been cultivated for many years in large areas in West Africa without high losses from blast (Notteghem, 1985;Bonman and Mackill, 1988). Five resistance genes have been identified in African cultivar, Moroberekan (Wang et al, 1994;Inukai et al, 1996;Naqvi and Chattoo, 1996;Chen et al, 1999).…”

“…(Shanmugam et al, 2001;Tang et al, 2002), and antifungal metabolites produced by Streptomyces spp. (Liao et al, 2009;Prabavathy, 2006) (Yang et al, 2017). Several rhizobacteria are known to detoxify the toxins produced by fungal pathogens and they have been developed as biocontrol agents to control fungal diseases of crop (Nagarajkumar et al, 2004).…”

Preliminary study on inhibitory activity of Enterobacter sp. strain KD111 isolated from the Cow feces

“…Various microorganisms such as Lactobacillus plantarum, Lactobacillus casei, Lactobacillus acidophilus, Bacillus subtilis, Enterococcus diacetylactis have been reported earlier from lower part of the gut of the cows (Ware et al, 1998). Other than these, Bacillus, Bifidobacterium and yeasts are also present in the rumen of the cow for better rumen fermentation (Kung, 2004;Yang et al, 2017). Antifungal substances isolated from cow dung inhibit the growth of coprophilous fungi (Dhama et al, 2005;Joseph and Sankarganesh, 2011;Dhama et al, 2013).…”