Crude oligosaccharides mediated resistance and histo-chemical changes in Capsicum annuum against anthracnose disease caused by Colletotrichum capsici

Abstract

Enhancing the host resistance using biotic elicitors is one of the eco-friendly approaches developed for plant disease management. The Crude Oligosaccharides (CO) extracted from Colletotrichum capsici (Syd.) Butler & Bisby was evaluated for their efficiency to elicit resistance in chilli against anthracnose disease. Among the different concentrations tested, CO treatment at 2.5 mg/ml concentration for 3 h duration significantly enhanced seed germination (90.5%) and seedling vigor (986.7), compared to control which offered 78% of seed germination and 712.5 of seedling vigor. Application of CO at 2.5 mg/ml concentration also reduced the disease severity with a highest anthracnose disease protection of 68% under greenhouse conditions and enhanced the vegetative growth parameters compared to control. The induction of resistance was evident with higher expression of primary defense responses like hypersensitive response, deposition of lignin, callose, hydrogen peroxide and phenol when compared to control plants. There was a one fold increase in defense enzyme activities phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and lipoxygenase in crude oligosaccharide-treated inoculated seedlings when compared to susceptible inoculated seedlings which were similar to that of resistant inoculated seedlings where a maximum of 1.5-fold increase in enzyme activity was observed.

Keywords:

• Anthracnose disease
• crude oligosaccharides
• Capsicum annuum
• Defense-related enzymes
• histochemical changes
• induction of resistance

Acknowledgments

The first author is thankful to the University of Mysore for awarding fellowship (Special Cell for SC/ST) and UGC, New Delhi for awarding Rajiv Gandhi National Fellowship for undertaking Ph.D. Program. MCT is thankful to CSIR, Govt. of India, New Delhi for Research Associate Fellowship. The authors are also thankful to Institution of Excellence (IOE) Project Authorities, University of Mysore, DST, DST-FIST and UGC for financial assistance.