Research Article Silicon Mitigates Salinity Stress by Regulating the Physiology, Antioxidant Enzyme Activities, and Protein Expression in Capsicum annuum ‘Bugwang’ Abinaya Manivannan, 1 Prabhakaran Soundararajan, 1 Sowbiya Muneer, 1 Chung Ho Ko, 1 and Byoung Ryong Jeong 1,2,3 1 Division of Applied Life Science (BK21 Plus), Graduate School, Gyeongsang National University, Jinju 660-701, Republic of Korea 2 Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea 3 Research Institute of Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea Correspondence should be addressed to Byoung Ryong Jeong; brjeong@gmail.com Received 18 December 2015; Accepted 22 February 2016 Academic Editor: Pengjun Shi Copyright © 2016 Abinaya Manivannan et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Silicon- (Si-) induced salinity stress resistance was demonstrated at physiological and proteomic levels in Capsicum annuum for the frst time. Seedlings of C. annuum were hydroponically treated with NaCl (50 mM) with or without Si (1.8 mM) for 15 days. Te results illustrated that saline conditions signifcantly reduced plant growth and biomass and photosynthetic parameters and increased the electrolyte leakage potential, lipid peroxidation, and hydrogen peroxide level. However, supplementation of Si allowed the plants to recover from salinity stress by improving their physiology and photosynthesis. During salinity stress, Si prevented oxidative damage by increasing the activities of antioxidant enzymes. Furthermore, Si supplementation recovered the nutrient imbalance that had occurred during salinity stress. Additionally, proteomic analysis by two-dimensional gel electrophoresis (2DE) followed by matrix-assisted laser desorption/ionization time-of-fight mass spectrometry (MALDI-TOF-MS) revealed that Si treatment upregulated the accumulation of proteins involved in several metabolic processes, particularly those associated with nucleotide binding and transferase activity. Moreover, Si modulated the expression of vital proteins involved in ubiquitin-mediated nucleosome pathway and carbohydrate metabolism. Overall, the results illustrate that Si application induced resistance against salinity stress in C. annuum by regulating the physiology, antioxidant metabolism, and protein expression. 1. Introduction Salinity is a major abiotic stress that limits the growth and yield of agricultural and horticultural crops worldwide. Primarily, salinity hampers the osmotic balance in plants by afecting the electrochemical gradients and vascular trans- portation of solutes [1]. In higher plants, salt stress leads to several physiological and metabolic modulations such as retardation of photosynthesis, ion toxicity, oxidative burst, and nutrient imbalance [2–5]. In addition, higher accumu- lation of Na + and Cl − ions during saline conditions hinders the uptake of essential nutrients [6]. Furthermore, salinity accelerates the production of harmful reactive oxygen species (ROS) that cause oxidative damage to proteins, lipids, and nucleic acids by afecting normal cellular metabolism [7]. Hence, an alternative strategy of silicon (Si) supplementation to overcome the negative efects of salinity in plants can be considered as a valuable approach. Silicon is the second most abundant element in the Earth’s crust, covering 27.70% of the lithosphere. Te essential roles of Si in plant systems have been extensively studied by numerous plant biologists for several years, but by defnition Si is considered as a “quasi-essential” or nonessential element for plants, because most plant species can complete their life cycle without it [8]. However, there are several hypotheses concerning the physiological functions of Si in monocots Hindawi Publishing Corporation BioMed Research International Volume 2016, Article ID 3076357, 14 pages http://dx.doi.org/10.1155/2016/3076357