Study On Localization Of Novel 57H-Mutant Gene In Rice

Glutelins and prolamins, the major storage proteins in rice, are greatly responsible for the quality of rice proteins. Glutelins and prolamins are synthesized in the ER which are finally accumulated into the vacuolar PB (PB-II) and the ER-derived PB (PB-I) in developing endosperm cell of the wild type rice, respectively. The 57H mutations, causing the high increase of 57 kDa glutelin precursor and the remarkable decrease of mature glutelins, have been involed in the accumulation of storage proteins. In the preliminary study, a novel 57H mutant(GPHl) obtained that had both the alteration of the lack of 13 kDa prolamin and the great increasing of glutelin precursor. The 57H mutant is result from a novel non-allelic 57H monogenic mutation, which is dominant mutation and has dosage effect. In this study, in order to ascertain new genetic informaiton concerning synthesis and expression of storage proteins in rice, localization of the mutant gene in GPH1 have been performed, adopting the map-based cloning method including SDS-PAGE, DNA electrophoresis and SSR/Indel-based PCR techniques, associating with database of IRGSP, Gramene and NCBI.Firstly,9311 and GPH1/2/3 were determined as the suitable combinations for novel 57H-mutant genes localization, by analyzing of the SSR polymorphism between novel 57H mutants (GPH1、GPH2、GPH3) and the typical Indica cultivars (9311、N22、IR36、Kasalath) with 510 SSR markers covering 12 rice chromosomes. The localizing populations were constructed by cultivating the F2 and F3 generations of the suitable combinations. Further preliminary mapping was performed by analyzing 166 F2/F3 generations from the cross between GPH1 and 9311 with 236 SSR and 72 Indel polymorphic markers. The gene in GPH1 was preliminarily mapped within 0.6 cM region between OJ1 and LS6 on chromosome 12. The GPH1-mutant gene might be related to the four predicted genes which encoded the zinc finger DHHC domain containing protein, heterogeneous nuclear ribonucleoprotein H3(hnRNP H3)analogue, Pentatricopeptide repeat domain containing protein and S16-like of 40S ribosomal protein. The functions of four genes involved in regulating transcription and posttranscriptional processing of genetic information and protein synthesis. Physical map, fine mapping and functions analysis of GPHl mutation genes will be conducted by expanding localizing populations and exploiting novel markers in the next step. The progress of this study has laid a solid foundation for isolation and cloning of the gene in GPH1 and other genes in novel 57H mutation, and is also important to grasp genetic mechanism about regulating synthesis and expression of storage proteins in rice and breeding for improving the quality of rice proteins.