Analysis of Protein Content and Genetic Diversity in Pea Germplasm in Tibet

To grasp protein content and composition of pea resource in Tibet Plateau, 54 pea materials from different eco-geographical environments of Tibet were collected and arranged in this paper. Based on SDS-PAGE, electrophoresis and genetic diversity analysis of water-solubility and salt-solubility proteins from 54 pea materials were conducted, and the relationship between geographical ecological factors（longitude, latitude and altitude）and total protein content was studied. The research results showed that total protein contents of 54 pea materials were between 17.58% and 28.67%, in which water-solubility protein accounted for 86.12%-91.40%, while salt-solubility protein accounted for 4.76-8.29%. Total protein content of Tibet pea showed significantly positive correlation with longitude, certain positive correlation with latitude and certain negative correlation with altitude. SDS-PAGE of water-solubility and salt-solubility proteins from 54 pea materials respectively detected 1588 and 699 protein bands. Based on different mobility ratios, there were 43 kinds of water-solubility protein bands, and diversity index was between 0 and 0.5. Its relative molecular weight was between 24.87 and 149.54 ku, showing the low molecular weight region of 24.71-50.41 ku and high molecular weight region of 56.34-88.08 ku. There were 24 salt-solubility protein bands based on different mobility ratios, with the diversity index of 0-0.5, and relative molecular weight was between 24.85 and 91.24 ku. According to the altitude, 54 pea resources were divided into 4 geographical groups. Gene diversity indexes of each group were respectively 0.23, 0.18, 0.35 and 0.31, and Shannon information indexes were respectively 0.33, 0.41, 0.52 and 0.46. It showed that the variation of pea protein was related to altitude. In clustering analysis, the tested resources were divided into seven classes, showing that water-solubility and salt-solubility proteins could reflect genetic relationship among germplasm resources at certain degree. The research could provide theoretical basis for the development of Tibet pea resources and selection of good parents.