Universal Journal of Plant Science 2(1): 14-18, 2014 http://www.hrpub.org DOI: 10.13189/ujps.2014.020102 Foliar Application of Salicylic Acid Stimulates Flowering and Induce Defense Related Proteins in Finger Millet Plants Manikandan Appu, Sathiyabama Muthukrishnan * Department of Plant Science, Bharathidasan University, Tiruchirappalli-620024, TamilNadu, India *Corresponding Author: sathiyabamam@yahoo.com Copyright © 2014 Horizon Research Publishing All rights reserved. Abstract Induction of defense related proteins, such as chitinase, protease inhibitor, peroxidase, polyphenol oxidase was studied in finger millet plants treated with salicylic acid. Treated plants showed changes in the isoform pattern with new isoformsof chitinase,protease inhibitor, peroxidase, and polyphenol oxidase. Salicylic acid (SA) treatment stimulates flowering and grain set. Induction of defense related proteins in salicylic acid treated finger millet plants may play a role in disease resistance. Keywords Finger Millet, Salicylic Acid, Chitinase, Protease Inhibitor, Peroxidase, Polyphenol Oxidase 1. Introduction Finger millet (Eleusine coracana L.) is an important cereal in East Africa and India [1]. Nutritionally, finger millet is equal or superior to other staple cereals, especially in minerals [2]. Finger millet is susceptible to more than twenty pathogens [3] and results in yield loss. SA treatment is known to activate plant systemic resistance commonly associated with activation of defense genes [4, 5,6,7]. We have reported earlier that SA treatment to groundnut leaves induced defense proteins in intercellular washing fluid [8] and promotes resistance towards Puccinia arachidis. Hence, an attempt has been made to induce antifungal hydrolases such as chitinase, protease inhibitor, peroxidase, polyphenol oxidase in finger millet plants by spraying with SA. The primary objective of this study was to characterize the effects of SA spray on induction of defense proteins such as chitinase, protease inhibitor, peroxidase, polyphenol oxidase in finger millet plants. 2. Materials and Methods 2.1. Plant Material Seeds of susceptible (IE 2572) cultivar of ragi were obtained from ICRISAT, and hrapradesh, India. 2.2. Salicylic Acid Preparation Different concentrations of SA (0.1mM, 0.5mM, 0.75mm) were prepared as described earlier [8]. 2.3. InVitro Seed Germination Test Seeds were imbibed (50 seeds/ 5ml) in different concentration of SA (0.1mM, 0.5mM, 0.75mm) and kept in a rocker overnight. Seeds immersed in water served as control. The seeds were then kept on a petri plate and allowed to germinate under moist condition. The percentage of germination was measured at 12, 24h. 2.4. Application of Salicylic Acid to Finger Millet Plants Finger millet seeds were washed thoroughly in distilled water and placed in an earthen pot (5seeds/pot) containing soil and manure. They were grown under glass house condition. To 35day old finger millet plants 0.1mM of SA was applied as a foliar spray. Water sprayed plants served as control. For each experiment, 20 plants were used in replicates and the experiments were repeated twice. Leaves from treated and control plants were removed after 10, 20 days and used for protein extraction. 2.5. Protein Extraction and Estimation Proteins were extracted using 0.01M Tris- HCl buffer, pH 6.8 (1g/2ml). They were centrifuged at 10,000G for 10 minutes and soluble fraction was used for estimation of protein and further enzyme localization. Protein present in the soluble fraction was estimated by Bradford’s method [9].