Study of protein changes in alfalfa (Medicago sativa L.) in normal conditions and under the tension from alfalfa weevil (Hypera postica Gyll.) feeding

The use of resistant cultivars is one of the safest and most profitable methods of controlling post including alfalfa weevil. After farm and greenhouse evaluating, Tafresh 42 genotype for molecular studies selected and evaluated to examine the pattern of protein expression in stress and non-stress conditions to alfalfa weevil. The Changes in protein expression were investigated using two-dimensional electrophoresis gels. Clustering analysis, principal component analysis and discriminant analysis were used in statistic studies. The results showed that 11 protein spots had expression changes among 218 protein spots. The most expression pattern of proteins with a similar increase in Tafresh 42, was related to a specific group of proteins which had 45.46% variations in the expression response to the stress. From the point of protein expression, cluster analysis caused a dividing of proteins into three main clusters indicating the presence of proteins with a similar performance in each cluster. Therefore, the presence of these proteins in a common biologic pathway is confirmed. The analysis of discriminant function confirmed 100% the results from clustering that indicated protein conformity with the conditions of the experiment. It is concluded that by using statistical analysis and software, it is possible to evaluate significant expression changes induced damage alfalfa weevil in proteome level and determine the index changes, and after that genetic engineering is utilized for enhancing the level of resistance in the plant under studying.