ROLE OF DEFENCE ENZYMES ACTIVITY IN RICE AS INDUCED BY IDM FORMULATIONS AGAINST SHEATH BLIGHT CAUSED BY RHIZOCTONIA SOLANI

Publication Date : 17/04/2016


Author(s) :

T. SUTHIN RAJ , P. ANNA JOICE , D. ANANDEESWARI , H. ANN SUJI.


Volume/Issue :
Volume 2
,
Issue 4
(04 - 2016)



Abstract :

Integrated disease management (IDM) of rice sheath blight is gaining momentum and encompasses all the available control methods with each method compensating the deficiencies of others. Among the available IDM practices, combined use of chemical, cultural, biological and host plant resistance is a common phenomenon.Combined applications of bio agent with chemical fungicides are an important IDM package against sheath blight disease. The use of fungal bioagents in controlling rice sheath blight in an IDM is gaining more importance.The combination of seaweeds, Annamalai mixture with P. fluorescens was used for the Integrated Disease Management.Induction of defence enzymes in crop plants treated with bio-control agents and challenged with the pathogen. Defense reaction occurs due to accumulation of peroxidase, phenylalanine ammonia lyase and PR-protein like -1, 3-glucanase etc. by estimating theses enzyme activity helpful to study the role of these enzymes in defence against the plant pathogen. Among the various treatment, the plants treated with S. wightii, P. fluorescens and Annamalai mixture (seed, prophylactic spraying at 20, 35 and 50 DAT) followed by challenge inoculated with R. solani (T6) recorded a maximum induction of β -1,3-glucanase activity 76.2 µg of Glucose released/min/g of fresh tissue on 7th day after pathogen inoculation. Among the various treatment, the plants treated with S. wightii, P. fluorescens and Annamalai mixture (seed, prophylactic spraying at 20, 35 and 50 DAT) followed by challenge inoculated with R. solani (T6) recorded maximum induction of Peroxidase activity (61.11 changes in absorbance/min/g of fresh tissue) at 7th day after pathogen inoculation. Application of S. wightii, P. fluorescens and Annamalai mixture (seed,prophylactic spraying at 20, 35 and 50 DAT) followed by challenge inoculated with R. solani (T6) recorded maximum induction of PPO activity(3.50 changes in absorbance/min/g of fresh tissue) at 7th day, which decreased further. PAL activity was found to increase significantly in plants treated with S. wightii, P. fluorescens and Annamalai mixture (seed, prophylactic spraying at 20, 35 and 50 DAT) followed by challenge inoculated with R. solani (T6) recorded maximum induction of PAL activity (5.20 changes in absorbance/min/g of fresh tissue) at 7th day there after it decreased. In conclusion, prior treatment of combined application of S. wightii, P. fluorescens and Annamalai mixture (seed, prophylactic spraying at 20, 35 and 50 DAT) (T5) followed by challenge inoculation with R. solani triggered the plant mediated defense mechanism that in turn reduce the sheath blight incidence in rice.


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