Chitinase production byBacillus subtilisATCC 11774 and its effect on biocontrol ofRhizoctoniadiseases of potato

Abstract

Stem canker and black scurf of potato, caused by Rhizoctonia solani, can be serious diseases causing an economically significant damage. Biocontrol activity of Bacillus subtilis ATCC 11774 against the Rhizoctonia diseases of potato was investigated in this study. Chitinase enzyme was optimally produced by B. subtilis under batch fermentation conditions similar to those of the potato-growing soil. The maximum chitinase was obtained at initial pH 8 and 30 °C. In vitro, the lytic action of the B. subtilis chitinase was detected releasing 355 μg GlcNAc ml -1 from the cell wall extract of R. solani and suggesting the presence of various chitinase enzymes in the bacterial filtrate. In dual culture test, the antagonistic behavior of B. subtilis resulted in the inhibition of the radial growth of R. solani by 48.1% after 4 days. Moreover, the extracted B. subtilis chitinase reduced the growth of R. solani by 42.3% when incorporated with the PDA plates. Under greenhouse conditions, application of a bacterial suspension of B. subtilis at 10 9 cell mL -1 significantly reduced the disease incidence of stem canker and black scurf to 22.3 and 30%, respectively. In addition, it significantly improved some biochemical parameters, growth and tubers yield. Our findings indicate two points; firstly, B. subtilis possesses a good biocontrol activity against Rhizoctonia diseases of potato, secondly, the harmonization and suitability of the soil conditions to the growth and activity of B. subtilis guaranteed a high controlling capacity against the target pathogen.

The Significance of Bacillus spp. in Disease Suppression and Growth Promotion of Field and Vegetable Crops

“…Chitinases (EC 3.2.1.14) are glycoside hydrolases (GHs) which degrade the β-1,4-glycosidic bonds in chitin, the second most abundant naturally available polysaccharide after cellulose, and the main component of the fungal cell wall [ 54 ]. Bacteria primarily produce chitinases in order to degrade chitin for its utilization as an energy source, whereas some bacterial chitinases are prospective biological control agents against a variety of plant diseases caused by phytopathogenic fungi [ 47 , 55 ]. Chitosanases (E.C.…”

Isolates of Bacillus sp. from garlic: effect on corn development and plant growth-promoting mechanisms

“…No transparent halos were observed around the bacterial colonies for chitinase and protease tests, indicating absence of enzymes or activity by the isolates. However, many reports described the genus Bacillus efficiency in producing such enzymes (Costa et al, 2010;Saber et al, 2015;Rais et al, 2017).…”

Overexpression of Chitinase A Gene from Serratia marcescens in Bacillus subtilis and Characterization of Enhanced Chitinolytic Activity

“…Therefore, the optimum temperature for chitinase activity in B. subtilis 168 carrying chiA from S. marcescens was determined as 60 o C. The optimum temperature for chitinase activity in S. marcescens was reported as 45 o C [18] and 50 o C [19,20]. The chitinase activity in different strains of B. subtilis showed highest activity at 30 o C [15], 50 o C [14,34] or 60 o C [4]. Optimum temperature for chitinase from B. subtilis expressed in E. coli was reported as 40 o C [13].…”

“…Chitinases of B. subtilis TV-125 isolated from plants were characterized and their antifungal activity against F. culmorum was reported [14]. Biocontrol capacity of B. subtilis ATCC 11774 against the Rhizoctonia solani was shown by Saber and coauthors [15]. There are some studies on the production of recombinant chitinase as well.…”