Elicitors are the synthetic or naturally occurring molecules, which capable of trigger the plant defense mechanism against the plant pathogens and environmental hazards. Plants deploy a number of defense mechanism against the phytopathogens and elicitors can able to induce the production of secondary metabolites to facilitate the biochemical defense mechanism, which eventually leads to plant resistance. Biotic elicitors are the type of elicitors that have the biological origin and derived from the pathogen or from the plant itself. To induce the plant resistant, initially biotic elicitors need to go through with microbial-associated molecular patterns (MAMPs, also called PAMPs). As well, the plants have evolved other receptors to detect the elicitors and leads to gene mediate resistance mechanism against the pathogens. This review discusses such biotic elicitors and their way to induce the disease resistance.

The effect of Pseudomonas syringae on morphological and antioxidant enzyme of Lablab purpureus L. (Sweet) was studied. Jasmonic acid are important endogenous chemical signals that play a key role in enhancing plant defense response Pseudomonas syringae cultures were injected into the stem region of 15 days old Lablab purpureus seedlings. Manual injection was found to be successful in inducing brown spot of Pseudomonas syringae. Post treatment of JA given as foliar spray resulted in enhance in the plant defense response. It was found that the level of Peroxidase, Polyphenol oxidase, Catalase and SOD was affected to a level of 85%, 35%, 44% and 60% respectively. Post treatment of JA at 0.5 µM, 1 µM, 2 µM and 5 µM each for 3 days resulted in enhanced resistance to brown spot disease. JA caused alleviation of responses induced by the pathogen in all aspects. Thus, JA treatment was found out to be considerably beneficial in reducing symptoms protecting the Lablab against the pathogen.

Anthracnose is a major and most common fungal disease of different angiospermic plants throughout the world. In the present study Colletotrichum lindemuthianum (COL) culture obtained from MTCC, Chandigarh were subcultured in PCA medium and the broth was inoculated into healthy 45-d-old cotton seedlings.

In this study, changes in some enzymatic activities in different tuber parts of "Florido" and "Bètè-bètè" cultivars belonging to Dioscorea alata species were investigated during post-harvest storage. Indeed, the studied enzymatic activities were those of acid phosphatase and pNP-glycosidases (α-glucosidase, α-fucosidase, α- galactosidase, β-glucosidase and β-galactosidase, α-mannosidase) and polysaccharidases (amylase, cellulase and inulinase). The results showed that the different tuber parts of both cultivars contained acid phosphatase and α-mannosidase activities. Besides, "Bètè-bètè" cultivar also possessed α-galactosidase. As for the polysaccharidases activities, the different parts of both cultivars had amylase and cellulase activities. Otherwise, the detected acid phosphatase, α-mannosidase and α- galactosidase activities in yam tuber part decreased with the storage time while the amylase and cellulase activities increased with the storage time. The enzymatic activities were found to be high in the distal tuber part for both cultivars. This work revealed that both cultivars didn’t contain α-glucosidase, α-fucosidase, α-galactosidase, β-glucosidase, β-galactosidase and inulinase activities. Our results could constitute an attractive biochemistry in the understanding of yams physiology during post-harvest storage.