Proteomic changes in the grains of foxtail millet (Setaria italica (L.) Beau) under drought stress

Abstract

Drought has become a serious problem that threatens global food security. Foxtail millet (Setaria italica) can be used as a model crop for drought-resistant research because of its excellent performance in drought tolerance. In this study, the typical drought-tolerant foxtail millet landrace ‘Huangjinmiao’ was grown in a field under control and drought stress conditions to investigate its response to drought stress. The proteins in the harvested grains were analysed through two-dimensional electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization-tandem time-of-flight (MALDI-TOF/TOF) analysis to characterize the response of foxtail millet under drought stress at a proteomic level. A total of 104 differentially abundant protein spots (DAPs) were identified; among them, 57 were up-regulated and 47 were down-regulated under drought treatment. The identified proteins were involved in an extensive range of biological processes, including storage proteins, protein folding, starch and sucrose metabolism, glycolysis/gluconeogenesis, biosynthesis of amino acids, detoxification and defense, protein degradation, tricarboxylic acid (TCA) cycle, protein synthesis, energy metabolism, transporter, pentose phosphate pathway, and signal transduction. Post-translational protein modifications might also occur. Moreover, the albumin content greatly decreased under drought stress, whereas the gliadin content considerably increased (p<0.01). In conclusion, this study provides new information on the proteomic changes in foxtail millet under drought stress and a framework for further studies on the function of these identified proteins.