Comparative proteomic analysis of alfalfa revealed new salt and drought stress-related factors involved in seed germination

Mol Biol Rep. 2017 Jul;44(3):261-272. doi: 10.1007/s11033-017-4104-5. Epub 2017 Jun 9.

Abstract

Salinity and drought are two major environmental factors that limit the growth and yield of many forage crops in semi-arid and arid regions. Alfalfa (Medicago sativa L.) is one of the most important forage crops in many countries. We aim to investigate the molecular mechanisms of alfalfa in response to salt and drought stresses in this study. Physiological and proteomic analyses were applied to examine the Zhongmu NO.3 alfalfa seed germination stage with 200 mM NaCl and 180 g·L-1 polyethylene glycol (PEG) treatments. The germination ability of the seed and the accumulation of osmotic solutes were quite different between the NaCl and PEG treatments. More than 800 protein spots were detected by proteomics technology on two-dimensional electrophoresis (2-DE) gels. The abundance of twenty-eight proteins were decreased or increased after salt and drought stress. Seventeen of these proteins were identified and classified into six functional categories through mass spectrometry (MS). The six groups involved in salt- and PEG-mediated stress included defense response, energy metabolism, protein synthesis and degradation, oxidative stress, carbohydrate metabolism-associated proteins, and unknown proteins. We discovered that some proteins related to carbohydrate metabolism and energy production increased in abundance under salt- and PEG-mediated drought stress. This demonstrates a common mechanism of energy consumption during abiotic stresses. Further study of these proteins with unknown function will provide insights into the molecular mechanisms of abiotic stress and the discovery of new candidate markers.

Keywords: Alfalfa; Drought stress; Proteomics; Salt stress; Seed germination.

MeSH terms

  • Carbohydrate Metabolism
  • Droughts
  • Energy Metabolism
  • Germination*
  • Medicago sativa / metabolism*
  • Medicago sativa / physiology
  • Oxidative Stress
  • Plant Proteins / metabolism
  • Plant Proteins / physiology*
  • Protein Biosynthesis
  • Proteomics
  • Seeds / metabolism*
  • Sodium Chloride
  • Stress, Physiological*

Substances

  • Plant Proteins
  • Sodium Chloride