Induction of pathogenesis-related proteins during biocontrol of Rhizoctonia solani with Pseudomonas aureofaciens in soybean (Glycine max L. Merr.) plants

Abstract

To investigate the biocontrol effectiveness of the antibiotic producing bacterium, Pseudomonas aureofaciens 63-28 against the phytopathogen Rhizoctonia solani AG-4 on Petri plates and in soybean roots, growth response and induction of PR-proteins were estimated after inoculation with P. aureofaciens 63-28 (P), with R. solani AG-4 (R), or with P. aureofaciens 63-28 + R. solani AG-4 (P + R). P. aureofaciens 63-28 showed strong antifungal activity against R. solani AG-4 pathogens in Petri plates. Treatment with P. aureofaciens 63-28 alone increased the emergence rate, shoot fresh weight, shoot dry weight and root fresh weight at 7 days after inoculation, when compared to R. solani AG-4; P + R treatment showed similar effects. Peroxidase (POD) and b-1,3-glucanase activity of P. aureofaciens 63-28 treated roots increased by 41.1 and 49.9%, respectively, compared to control roots. POD was 26% greater in P + R treated roots than R. solani treated roots. Two POD isozymes (59 and 27 kDa) were strongly induced in P + R treated roots. The apparent molecular weight of chitinase from treated roots, as determined through SDS-PAGE separation and comparison with standards, was about 29 kDa. Five b-1,3-glucanase isozymes (80, 70, 50, 46 and 19 kDa) were observed in all treatments. These results suggest that inoculation of soybean plants with P. aureofaciens 63-28 elevates plant growth inhibition by R. solani AG-4 and activates PR-proteins, potentially through induction of systemic resistance mechanisms.

Induction of Defense Response Against Rhizoctonia solani in Cucumber Plants by Endophytic Bacterium Bacillus thuringiensis GS1

“…The change in chitinase activity in plants in response to antagonist and/or phytopathogens has been well demonstrated in cases such as the control of R. solani by P. aureofaciens in soybean [23] and sheath blight caused by R. solani in rice cultivars [48]. In the present study, the highest chitinase activity was observed in RS-treated cucumber plants at 4 days after treatment (Fig.…”

“…In addition, the β-1,3-glucanase activity of GS1treated cucumber plants was increased 1.7-fold compared with the control. β-1,3-Glucanase activity in plants has been demonstrated in the control of Botrytis cinerea by selected grapevine-associated bacteria [33] and the control of R. solani by P. aureofaciens in soybean plants [23]. Furthermore, recent studies have provided evidence that β-1,3-glucanase plays a role in several developmental processes [49,55].…”

“…6B). Jung et al [23] reported that five β-1,3-glucanase isozymes (80, 70, 50, 46, and 19 kDa) were present in soybean plants. The accumulation of the 33 kDa β-1,3-glucanase isoform observed in the present study was correlated with an increase in its level of translatable mRNA that was observed in response to infection with the fungus Fusarium moniliforme [11].…”

Variable responses of soybean chitinases to arsenic and cadmium stress at the whole plant level

“…In previous reports the number of chitinases (identified using glycol chitin as a substrate) varied in soybean roots grown at normal conditions. Single isoform of 29 and 32 kDa were detected by Jung et al (2007) and Gijzen et al (2001) (respectively). Two isoforms of 31 and 46 kDa were detected by Xie et al (1999), and of undetermined size by Qiu et al (1997).…”

Induction of defense responses against Magnaporthe oryzae in rice seedling by a new potential biocontrol agent Streptomyces JD211

“…Leaf samples (0.5 g) were homogenized in 10 ml of 0.1 M sodium acetate buffer (pH 5.0) to obtain the crude enzyme. β‐1,3‐glucanase was estimated by incubating 1.5 ml laminarin (0.1% w/v) in sodium acetate buffer with 1.0 ml crude enzyme at 37 °C for 15 min . Then 1.5 ml 3‐amino‐5‐nitrosalicylicacid (DNS) was added, and the mixture heated in a boiling water bath for 5 min.…”