Proteomic Analysis of Salt Tolerance in Sugar Beet Monosomic Addition Line M14

Understanding
the mechanisms of plant salinity tolerance can facilitate
plant engineering for enhanced salt stress tolerance. Sugar beet monosomic
addition line M14 obtained from the intercross between Beta vulgaris L. and Beta corolliflora Zoss exhibits tolerance
to salt stress. Here we report the salt-responsive characteristics
of the M14 plants under 0, 200, and 400 mM NaCl conditions using quantitative
proteomics approaches. Proteins from control and the salt treated
M14 plants were separated using 2D-DIGE. Eighty-six protein spots
representing 67 unique proteins in leaves and 22 protein spots representing
22 unique proteins in roots were identified. In addition, iTRAQ LC–MS/MS
was employed to identify and quantify differentially expressed proteins
under salt stress. Seventy-five differentially expressed proteins
in leaves and 43 differentially expressed proteins in roots were identified.
The proteins were mainly involved in photosynthesis, energy, metabolism,
protein folding and degradation, and stress and defense. Moreover,
gene transcription data obtained from the same samples were compared
to the corresponding protein data. Thirteen proteins in leaves and
12 in roots showed significant correlation in gene expression and
protein levels. These results suggest the important processes for
the M14 tolerance to salt stress include enhancement of photosynthesis
and energy metabolism, accumulation of osmolyte and antioxidant enzymes,
and regulation of methionine metabolism and ion uptake/exclusion.