Proteome analysis of sesame leaves in response to waterlogging stress at vegetative and flowering stages

Waterlogging, a major environmental stress, impairs plant growth and development and induces synthesis of different proteins. To understand the molecular mechanisms coupled with morpho-physiological alterations underlying waterlogging tolerance, the LTQ-FTICR MS/MS technique was employed to map the proteomes of leaves of sesame grown under control and waterlogged conditions. The waterlogging treatment caused dramatic alterations in morphological and biochemical properties of the leaves of sesame. For proteome analysis, more than 75 reproducible protein spots were identified on 2-DE gels wherein 51 protein spots (≥ 1.5-fold change) were used for analysis by mass spectrometry. Among 51 differentially abundant proteins, 20 were specific to the 10-leaf stage and 31 were specific to the flowering stage. Most of the differentially abundant proteins were involved in group metabolism, and energy and stress defense. Oxygen-evolving enhancer protein 1, ATP synthase subunit, heat shock proteins, glutamine synthetase, glyceraldehyde-3-phosphate dehydrogenase, and superoxide dismutase were upregulated under waterlogging. However, the photosynthesis- and protein biosynthesis-related proteins (e.g., ribulose-1,5-bisphosphate carboxylase/oxygenase activase, and S-adenosylmethionine synthase 1) were down-regulated under waterlogging. The protein interaction network indicates that energy metabolism- and stress- and defense-related proteins were involved in the protein-protein interaction network, which could form an indispensable network in sesame leaves. To this end, physiological results highlighted the impairment of photosyntheis, which is consistent with results obtained at the proteome level. The upregulation of metabolism-, energy-, and stress defense-related proteins in response to waterlogging stress may provide new insights into the complex mechanisms underlying waterlogging tolerance in sesame.