Journal Article

Combined seed and foliar pre-treatments with exogenous methyl jasmonate and salicylic acid mitigate drought-induced stress in maize

Sajjad, Muhammad, Hassan, Muhammad Nadeem, Yasmin, Humaira, Nosheen, Asia, Tayyab, Nimrah, Roberts, Thomas H., Naz, Rabia, Keyani, Rumana

2020

Overview

Susceptibility of plants to abiotic stresses, including extreme temperatures, salinity and drought, poses an increasing threat to crop productivity worldwide. Here the drought-induced response of maize was modulated by applications of methyl jasmonate (MeJA) and salicylic acid (SA) to seeds prior to sowing and to leaves prior to stress treatment. Pot experiments were conducted to ascertain the effects of exogenous applications of these hormones on maize growth, physiology and biochemistry under drought stress and well-watered (control) conditions. Maize plants were subjected to single as well as combined pre-treatments of MeJA and SA. Drought stress severely affected maize morphology and reduced relative water content, above and below-ground biomass, rates of photosynthesis, and protein content. The prolonged water deficit also led to increased relative membrane permeability and oxidative stress induced by the production of malondialdehyde (from lipid peroxidation), lipoxygenase activity (LOX) and the production of H2O2. The single applications of MeJA and SA were not found to be effective in maize for drought tolerance while the combined pre-treatments with exogenous MeJA+SA mitigated the adverse effects of drought-induced oxidative stress, as reflected in lower levels of lipid peroxidation, LOX activity and H2O2. The same pre-treatment also maintained adequate water status of the plants under drought stress by increasing osmolytes including proline, total carbohydrate content and total soluble sugars. Furthermore, exogenous applications of MeJA+SA approximately doubled the activities of the antioxidant enzymes catalase, peroxidase and superoxide dismutase. Pre-treatment with MeJA alone gave the highest increase in drought-induced production of endogenous abscisic acid (ABA). Pre-treatment with MeJA+SA partially prevented drought-induced oxidative stress by modulating levels of osmolytes and endogenous ABA, as well as the activities of antioxidant enzymes. Taken together, the results show that seed and foliar pre-treatments with exogenous MeJA and/or SA can have positive effects on the responses of maize seedlings to drought.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Abiotic stress / Abscisic acid / Acetates - pharmacology / Agricultural production / Antioxidants / Antioxidants (Nutrients) / Antioxidants - metabolism / Biochemistry / Biology and Life Sciences / Carbohydrates / Carotenoids / Carotenoids - metabolism / Catalase / Chlorophyll - metabolism / Corn / Crop production / Cyclopentanes - pharmacology / Drought / Drought resistance / Droughts / Ecology and Environmental Sciences / EDTA / Enzymes / Extreme weather / Hormones / Hydrogen peroxide / Jasmonic acid / Leaves / Lipid peroxidation / Lipids / Lipoxygenase / Liquid oxygen / Loam soils / Malondialdehyde / Membrane permeability / Metabolism / Metabolites / Methods / Methyl jasmonate / Moisture content / Morphology / Osmolar Concentration / Oxidative stress / Oxidative Stress - drug effects / Oxylipins - pharmacology / Permeability / Peroxidase / Peroxidation / Phenols (Class of compounds) / Photosynthesis / Physiological aspects / Physiology / Plant biochemistry / Plant growth / Plant Growth Regulators - pharmacology / Plant hormones / Plant Proteins - metabolism / Povidone / Principal Component Analysis / Production management / Proline / Proteins / Research and Analysis Methods / Salicylic acid / Salicylic Acid - pharmacology / Salinity / Seedlings / Seeds / Seeds - drug effects / Soil / Stress, Physiological - drug effects / Sugar / Superoxide dismutase / Superoxides / Water / Water content / Water deficit / Zea mays - drug effects / Zea mays - growth & development / Zea mays - metabolism