Comparative Study On Seed Protein Components Among Different Buckwheat Varieties

Buckwheat belong to plants of genus Fagopyrum in dicotyledon Polygonaceae,which is one of the inportant minorcrops with health care function,Among them,there are two cultivated species: the common buckwheat and the tartary buckwheat.Buckwheat seed protein is not only one of the important nutritional components,but also has a variety of medicinal value.The composition and content of protein subunits in buckwheat seeds were related to the species and growth environment.In order to analyze the relationship between the composition and content of buckwheat seed protein subunits and environment,the seeds of 10 tartary buckwheat varieties and 10 common buckwheat varieties were planted in four places for analyzing the content variation of four kinds of protein components(namely albumin,globulin,prolamin and glutelin)and the SDS-PAGE spectrum.Besides,the proteomics of rice tartary buckwheat seeds at differrent development stages were also studied,so as to provide the basis for buckwheat protein quality breeding.The main results are as follows:1.The variations of seed protein component content among different buckwheat varieties and among different growing places: The contents of four kinds of protein in the seeds of the 10 tartary buckwheat varieties and 10 common buckwheat varieties planted in four places with different altitude(Altitude : Tibet > Qinghai > Hebei > Inner Mongolia)were studied,and the results showed:(1)the protein component contents followed the pattern in all the common buckwheat cultivars: albumin > glutelin > globulin > prolamin.Among fourdifferent altitude areas,the highest protein component contents of common buckwheat seeds in average are 4.750% of albumin in Qinghai(alt.2620 m),1.081% of globulin in Inner Mongolia,0.393% of prolamin in Shigatse,Tibet,and 2.805%of glutelin in Zhangjiakou,Hebei,respectively.(2)The glutenin is the most abundant in all the tartary buckwheat varieties,then followed by albumin.All the tartary buckwheat varieties contain less content of prolamin and globulin.Among four places,tartary buckwheat cultivated in Tibet has seed albumin content up to 2.925% and prolamin content of 1.281%,and those in Zhangjiakou,Hebei has the highest globulin content of 1.233% and glutenin content of 3.666%.(3)The varieties and the places are the key factors affecting the content of seed protein.2.The variation of seed protein bands of differrent buckwheat which planted in different locations: SDS-PAGE electrophoresis showed that there are similar albumin spectrums among buckwheat from four different altitudes,but the identifiable subunit bands of common buckwheat are more than these of tartary buckwheat.3.Proteomic analysis of seeds in different developmental stages of rice tartary buckwheat: In this study,we used two-dimensional electrophoresis and mass spectrometry to analyze the differentially expressed proteins in seeds of rice tartary buckwheat Mi 11 at different stages of seed maturation(The young fruit stage,filling stage and milk ripe stage),and identified 74 differentially expressed proteins in the seeds of Mi11.In comparison with the seed protein in young fruit period,there are 45 up-regulated proteins in the grain filling stage,and no significant changes in the expression of 19 proteins,and 10 down-regulated expression proteins.Similarly,there are 51 up-regulated proteins in the milk ripe stage,and no significant changes in the expression of 5 proteins,and the expression is down regulated by 18.The 74 differentially expressed proteins can be divided into 20 kinds of proteins involved in different biological processes,which are involved in the following 52 specific metabolic pathways.Among them,most involve in the development of metabolic proteins,such as11 S storage protein and pea globulin.In addition,1 unknown protein was discovered in this study.