Biocontrol Science and Technology (2015) 25, 444-459

Vahid Keshavarz Tohid and Parissa Taheri (2015)
Investigating binucleate Rhizoctonia induced defence responses in kidney bean against Rhizoctonia solani
Biocontrol Science and Technology 25 (4), 444-459
Abstract: Four isolates of binucleate Rhizoctonia spp. (BNR), including AG-Bb, AG-Ba, AG-G and AG-A, were evaluated for pathogenicity on kidney beans. AG-Bb was the least virulent on kidney bean, and it was used as biocontrol agent against damping-off caused by Rhizoctonia solani AG-4 HG-II. The inoculation of the bean seedlings with BNR (AG-Bb) reduced disease symptoms in the following treatments: seedlings inoculated with BNR and R. solani simultaneously and also in seedlings inoculated with BNR and R. solani with a one-week interval. An investigation into different time points showed that BNR-induced resistance gradually decreased and disappeared after two weeks. Enzyme assays showed that the peroxidase (POX) and catalase (CAT) activities of bean seedlings increased after R. solani inoculation. The greatest activity of POX and CAT was discovered in seedlings inoculated with BNR and R. solani simultaneously. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed a correlation between the expression of bean POX and CAT genes and the activity of the corresponding enzymes. The inoculation of leaf discs with BNR revealed the induction of resistance to R. solani. The leaf discs pretreated with sodium azide (NaN₃) as POX and CAT inhibitors had less resistance to R. solani compared to the control. These results showed the importance of the former enzymes to induce resistance in bean plants. BNR inoculation leads to H₂O₂ accumulation in leaf discs which is the main reactive oxygen species (ROS). H₂O₂ can act as a defence signal and also lead to an increase in the solidity of cell walls. BNR stimulates bean seedlings to produce antioxidant enzymes and ROS which can increase bean resistance to R. solani.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Parissa Taheri

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Rhizoctonia solani	Beans (Phaseolus)
Binucleate Rhizoctonia (antagonist)	Rhizoctonia solani	Beans (Phaseolus)