title: Abiotic elicitors mediated elicitation of innate immunity in tomato: an ex vivo comparison.
abstract: Improvement of the host resistance by using hazard free chemical elicitors is emerging as an alternative approach in the field of plant disease management. In our present work, we have screened the efficacy and possible mechanism of abiogenic elicitors like Dipotassium hydrogen orthophosphate(K2HPO4), Oxalic acid (OA), Isonicotinic acid (INA), Salicylic acid (SA), Acetylsalicylate (AS), Arachidonic acid (AA) and Calcium chloride (CaCl2) to stimulate innate immune responses inLycopersicum esculentumMill. Excised tomato leaves, treated with elicitors at three different concentrations, were found to stimulate defense and antioxidative enzymes, total phenol and flavonoid content after 24 h of incubation. CaCl2(0.5 %) followed by INA (2.5 mM) were found most effective in activation of all such defense molecules in tomato leaves. Furthermore, nitric oxide (NO), a key gaseous mediator in plant defense signaling, was also measured after subsequent elicitor application. Higher doses of elicitors showed an elevated level of reactive oxygen species (ROS) generation, enhanced lipid peroxidation rate and proline content, which indicates the extent of abiotic stress generation on the leaves. However, ROS production, lipid peroxidation rate and proline concentration remain significantly reduced as a result of CaCl2(0.5 %) and INA (2.5 mM) application. A sharp increase of total chlorophyll content was also recorded due to treatment of CaCl2(0.5 %). These results demonstrate the effects of different abiogenic elicitors to regulate the production of defense molecules. Results also suggest that among all such chemicals, CaCl2(0.5 %) and INA (2.5 mM) can be used as a potential elicitor in organic farming of tomato.
authors.affiliation: Molecular and Applied Mycology and Plant Pathology Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019 India ; Department of Botany, Scottish Church College, Kolkata, 700006 India.
authors.forename: Nilanjan
authors.initials: N
authors.lastname: Chakraborty
authors.affiliation: Department of Botany, Scottish Church College, Kolkata, 700006 India.
authors.forename: Sudeepa
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Molecular and Applied Mycology and Plant Pathology Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019 India.
authors.forename: Swarnendu
authors.initials: S
authors.lastname: Chandra
authors.affiliation: Molecular and Applied Mycology and Plant Pathology Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019 India.
authors.forename: Sarban
authors.initials: S
authors.lastname: Sengupta
authors.affiliation: Molecular and Applied Mycology and Plant Pathology Laboratory, Department of Botany, University of Calcutta, Kolkata, 700019 India.
authors.forename: Krishnendu
authors.initials: K
authors.lastname: Acharya
keywords: Antioxidative enzymes; Calcium chloride; Defense molecules; Nitric oxide; Reactive oxygen species; Total chlorophyll