Induction of bacterial blight (Xanthomonas oryzae pv. oryzae) resistance in rice by using systemic acquired resistance (SAR) and induced resistance (IR) on selected genotype.

Ashwarya L. Tandon; S.D. Chaliganjewar; N. Khare

Volume : V, Issue : II, February - 2016

Induction of bacterial blight (Xanthomonas oryzae pv. oryzae) resistance in rice by using systemic acquired resistance (SAR) and induced resistance (IR) on selected genotype.

Ashwarya L. Tandon, S. D. Chaliganjewar, N. Khare

Abstract :

 Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae is a common and destructive disease of rice (Oryza sativa). The disease can cause yield losses of 20 to 60 per cent (Adhikari et al., 1994; Exconde et al., 1971 and Ou, 1985). It is the most extensively studied disease with particular emphasis on resistant cultivars, their nature of resistance, explicitly of gene pyramiding for resistance, incorporation of wild source of resistance etc. Systemic acquired resistance (SAR) is the phenomenon whereby a plant’s own defense mechanisms are induced by prior treatment with either a biological or chemical agent. The use of SAR as part of a disease management strategy in relation to received little scientific investigation despite offering some potential for pathogen control. Whereas, Induced resistance (IR) is a physiological state of enhanced defensive capacity elicited by specific environmental stimuli, whereby the plant�s innate defens are potentiated against subsequent biotic challenges. The efficacy of salicylic acid, oxalloacetic acid (Chemical agent) and biological agents in enhancing systemic acquired resistance and induced resistance against bacterial blight development was studied in pyramid variety IRBB-60 possessing 4 resistance genes (i.e. Xa 4 + xa 5 + xa 13 + Xa 21) and IRBB-59 (possessing three resistance genes i.e. Xa 5 + xa 13 + Xa 21) respectively. Salicylic acid (100 ppm.), Salicylic acid (150 ppm), Salicylic acid (200 ppm), Oxalloacetic acid (100 ppm), Oxalloacetic acid (150 ppm), Oxalloacetic acid (200 ppm) and Control (only Water) were taken as treatments for SAR and Pseudomonas fluorescenes (2g/ liters); Pseudomonas fluorescenes (3g/ liters); Bacillus subtilis (2g/ liters); Bacillus subtilis (3g/ liters); Trichoderma harzianum (T4) (2g/ liters); Trichoderma viride (T12) (2g/ liters) and Control (only Water) for IR, respectively. Chemical agents and biological agents both could able to induce resistance in rice plants which was reflected in the forms of suppressed bacterial leaf blight severity / incidence as well as higher yield and yield components. Amongst chemical agents and their concentrations, Salicylic acid at 200ppm concentration could induce more resistance and thus effectively suppress disease severity as well as enhancing the yield and yield components i.e. bundle weight, grain weight etc. followed by oxalloacetic acid. Induced resistance was investigated taking into the consideration of microbial antagonism of Pseudomonas fluorescence and Bacillus subtilis as possible methods for control of bacterial blight of rice. Amongst biological agents, Pseudomonas fluorescence was found more effective in suppressing the disease severity as well as increasing yield and yield components than Bacillus subtilis. Present study therefore revealed that bacterial leaf blight severity can be suppressed up to certain level by inducing systemic acquired resistance and induced resistance using chemical and biological agents. Dempsley and Klessing (1995) also reported that salicylic acid induced resistance by signal mechanism inducing the biochemical activity.