Effect of salinity on growth and proteomic changes in two cultivars of mulberry (Morus alba L.) with contrasting salt tolerance

Abstract

The effect of salinity on growth and proteomic changes was studied in two cultivars of mulberry (Morus alba L.) with contrasting salt tolerance. Three-month-old mulberry plants were subjected to 0.0 (control), 1.0, 1.5 and 2.0% NaCl stress for 7 d. Salt treatment did affect the growth, dry matter and leaf area in both the cultivars. The cultivar S1 showed a lesser rate of decrease in growth, dry matter and leaf area than cultivar ATP which indicated that cultivar S1 is better tolerant than cultivar ATP to salt stress. Soluble proteins extracted from leaves were analyzed by two-dimensional electrophoresis in order to detect salt stress induced changes in the polypeptide patterns. Salt stress resulted in differential changes in protein level qualitatively and quantitatively in both the cultivars. More than 150 protein spots that were detected in leaves of both cultivars showed reproducible abundance within replications and significant response to salt treatment compared to unstressed. In cultivar S1, 33 proteins increased and 21 proteins decreased by different salt stress levels. Among these, protein spot # 10, 32, 33, 46 to 48 and 53 were specifically induced by NaCl treatments in S1 cultivar. In ATP cultivar, eight proteins increased and 43 proteins decreased and one protein spot (# 55) found to be specific to this cultivar. In general, salt stress resulted a much decrease in growth and total polypeptide profiles in the susceptible cultivar ATP, than tolerant cultivar S1.