| Glutelins and prolamins are the major storage proteins in rice seed. The glutelins, coded at least by 10 structural genes, are synthesized in the ER as 57kDa precursor polypeptides and deposited into the vacuolar protein body (PB-â…¡) as mature types of 40kDa acidic and 20kDa basic subunits. The 13-14kDa prolamin polypeptides, composed of two types components and containing 7-9 polypeptides, are synthesized in the ER and deposited into the ER-derived PB-I. The deposited proteins are important composition affecting quality of rice.In this study,3 types of 57H mutants with high amounts of 57kDa glutelin precursor and 3 types of 13-14kDa prolamin mutants were found, analyzing biochemical characters of storage proteins in 410 spontaneous rice germplasms with the SDS-PAGE technique. In comparison with the controlling germplasm with the wild phenotype of glutelin, the first type of 57H mutant showed the great increase of glutelin precursor and the remarkable decrease of the mature glutelins; the second type of 57H mutant only showed the great increase of glutelin precursor; the third type of 57H mutants showed the lack of the B and C species of 13-14kDa prolamin in addition to the increase of glutelin precursor. The 3 types of prolamin mutants showed the diversity in composition of 13-14kDa prolamins, compared with the controlling germplasm containing the A and B components of 13-14kDa prolamins. The first type of prolamin mutants was showed to contain the A, B and C components of the prolamins; the second type of prolamin mutants was showed to lack the B components; the third type of prolamin mutant was showed to lack the B but contain the C components. The spontaneous mutants for glutelins and prolamins could contain genic mutations affecting synthesis and accumulation of the proteins, and are considered to be useful genetic resources for the overall understanding of synthesis and accumulation of rice storage proteins and the breeding for rice proteins of good quality.
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