Salt‐resistant and salt‐sensitive wheat genotypes show similar biochemical reaction at protein level in the first phase of salt stress

Abstract

Salinity has a two-phase effect on plant growth, an osmotic effect due to salts in the outside solution and ion toxicity in a second phase due to salt build-up in transpiring leaves. To elucidate salt-resistance mechanisms in the first phase of salt stress, we studied the biochemical reaction of salt-resistant and salt-sensitive wheat (Triticum aestivum L.) genotypes at protein level after 10 d exposure to 125 mM-NaCl salinity (first phase of salt stress) and the variation of salt resistance among the genotypes after 30 d exposure to 125 mM-NaCl salinity (second phase of salt stress) in solution culture experiments in a growth chamber. The three genotypes differed significantly in absolute and relative shoot and root dry weights after 30 d exposure to NaCl salinity. SARC-1 produced the maximum and 7-Cerros the minimum shoot dry weights under salinity relative to control. A highly significant negative correlation (r 2 = -0.99) was observed between salt resistance (% shoot dry weight under salinity relative to control) and shoot Na + concentration of the wheat genotypes studied. However, the salt-resistant and salt-sensitive genotypes showed a similar biochemical reaction at the level of proteins after 10 d exposure to 125 mM NaCl. In both genotypes, the expression of more than 50% proteins was changed, but the difference between the genotypes in various categories of protein change (up-regulated, down-regulated, disappeared, and new-appeared) was only 1%-8%. It is concluded that the initial biochemical reaction to salinity at protein level in wheat is an unspecific response and not a specific adaptation to salinity.

Proteome analysis of sugar beet (Beta vulgaris L.) elucidates constitutive adaptation during the first phase of salt stress

“…Moreover, a dramatic change in protein pattern under low salt concentration does not necessarily affect biomass production and ion concentration. Similar conclusions were drawn by Saqib et al (2006) for salt-resistant and salt-sensitive genotypes of wheat. On the other hand, only a limited change in the proteomes of Oryza sativa and Nicotiana tobaccum were found under salt stress (Abbasi and Komatsu, 2004;Razavizadeh et al, 2009).…”

“…They concluded that this was a relatively non-specific proteomic response of maize to salt stress, which may indicate disorder of cytoplasmic enzymes due to higher Na + concentration in the cytoplasm. Under identical salt concentrations as those used in this study, the proteome of two wheat genotypes also showed a change of 60% and 79%, respectively (Saqib et al, 2006). Later, proteomic studies on halophytes showed that proteomic alterations under salt stress were specific and less pronounced compared to salt-sensitive plants.…”

Evaluation of Rice and Wheat Cultivars for Tolerance to Salinity and Sodicity in Soil

“…However, the varietal differences, in general, varied with various EC/SAR ratios. Earlier variations among different wheat genotypes for tolerance to salinity have been reported by Davenport et al (2005), Saqib, Zö rb, andSchubert (2006), and Saqib et al (2005). Qureshi, Hanif, and Sandhu (1976) reported a lower green-matter yield of wheat irrigated with unamended saline-sodic tube-well water than with gypsum-amended saline-sodic water.…”

Investigation of Plant Abiotic Stress Tolerance by Proteomics and Phosphoproteomics

“…A few proteins and signaling pathways were found to be commonly regulated among various stress stimuli, including metabolic proteins (carbohydrate, energy, nitrogen metabolism), compatible solutes, and stress-responsive proteins; protein synthesis, protein degradation, and protein turnover as well as reactive oxygen species formation and reactive oxygen species scavenging, including superoxide dismutase, ascorbate peroxidase, and glutathione reductase; and the phenylpropanoid pathway (Kosova et al 2011 ;Suzuki et al 2012 ;Böhmer and Schroeder 2011 ). In wheat, the fi rst response to salt stress is a nonspecifi c response that becomes more specifi c over the course of weeks (Saqib et al 2006 ). Also the initial responses to salt and water stress appear identical, and specifi city develops over a period of time (Munns 2002 ).…”