Studies On Polymorphism For Seed Storage Protein In Rice

Oryza sativa L. is the most important crop in the world which is planted vastly, and the yield of rice is quiet high every year. The storage protein of rice is mostly consisted in endosperm. It is classified four kinds of protein by its dissolvability. They are globin, albumin, prolamine and glutelin. Glutelin is the major storage protein and accounts for 80% of the total protein found in the rice grain. Promine is the second most important protein which accounts for 6% to 18% of the total protein.First rice prolamines were extracted from seeds of 8 lines on different conditions, and then measured the content of prolamine in every species of rice by ultraviolet absorbing. The results showed that the concentration of the extracting had a little effect on prolamine, but the effect of dual-extracting was obvious better than extracting only one time. Prolamine could be extracted entirety on the condition of 0.05g/mL of the scale between solid and liquid, temperature of 50℃and 12h. The centrifugal speed and time had little effect on the extracting of prolamine either. Then rice prolamines were extracted from the seeds of 4 lines with 6 different extracting solvents on the same conditions. The results showed that the extraction of prolamine was most efficient with the extracting solvent 100% ethylene glycol. Using this extractant, suitable prolamine bands could be resolved by SDS-PAGE, and its electrophoregram was clarity. Therefore, it was the best extractant for rice prolamines. Then 409 lines of rice promine, glutelin were extracted and mensurated by ultraviolet absorbing. The promine contents of them are probably between 4 mg/g-12 mg/g, in this area there are 288 lines which account for 70.44% of all the lines we mensurated. The highest line is about 144 times of the lowest one. The glutelin contents are probably between 20 mg/g-50 mg/g, there are 361 lines in this area and they account for 88.26%. The highest line is about 8.7 times of the lowest one.At last promine, glutelin, and total protein of some of the lines were analyzed by SDS-PAGE. Electrophoregram of every line is different from each other.The results showed that there are large polymorphisms not only in rice promine, glutelin compositions but also in their quantities and percentage among the lines studied.In conclusion, there are polymorphisms in storage protein of rice. Electrophoregrams of the extracted storage protein could be used to analyze the genetic diversity and phylogenesis of rice populations.