Study On The Function Of OsGT75 Gene Regulating Grain Shape In Rice

The coding gene OsGT75 forthe interacting protein of agrain shape regulatory protein was identified by yeast two-hybrid assay inlaboratory.The function of OsGT75 has not yet been reported.In this study,the T-DNA insertion mutant rice seeds of OsGT75 gene were purchased from Huazhong Agricultural University.After planting and molecular identification,gt75 homozygous mutants and segregated wild-type rice materials were obtained,the statistics results of grain shape showed that OsGT75 negatively regulated rice grain length.On this basis,a functional complementary expression vector of OsGT75 gene was constructed and transformed to gt75 homozygous mutant material to obtain corresponding transgenic plants.Through molecular identification and grain length analysis,it was further proved that OsGT75 negatively regulates rice grain length.In addition,the expression profile of OsGT75 was identified,and the subcellular localization analysis of the OsGT75 protein was carried out to help understand the biological function of OsGT75.This study can provide gene reserve for rice genetic and breeding research of grain shape.The specific research results are as follows:1.The OsGT75 gene is located on rice chromosome 7 with 3270 bp length of CDS encoding 1089 amino acids,and the encoded protein contains a DUF4378 functional domain.The promoter region of OsGT75 contains a variety of hormone response,light response,growth and development,anaerobic induction related cis-acting elements.2.The statistical results for seed length of gt75 homozygous mutant(HO)and segregated wild-type(WT)materials showed that the average grain length of HO seeds with glumes was 8.34 mm,and thatwithout glumes was 5.77 mm;the average grain length of WT seeds with glumes was 7.76 mm,and that without glumeswas5.39 mm;the T test results showed that the average grain lengths of HO and WT seeds with or without glumes all were significantly different.3.The tissue expression profile detection results showed that the transcriptional expression level of OsGT75 in panicle tissue was much higher than its expression level in root,stem,leaf or leaf sheath;during the developmental process of rice panicle,the expression level of OsGT75 increased gradually in the early stage,and was relatively highest in 10 cm young panicle;hereafter its expression decreased gradually in pace with panicle elongation.4.The full-length CDS of OsGT75 without the stop codon was amplified,its subcellular localization vector p YBA-1132-OsGT75 has been constructed by homologous recombination and transferedinto rice protoplasts.The confocallaserscanningmicroscopeobservation showed that the expressed protein of OsGT75 was localized in the nucleus.5.The full-length CDS of OsGT75 gene was cloned to construct its complementary expression vector p CAMBIA2300s-OsGT75,and then the constructed vector was genetically transformed into homozygous mutant gt75 by Agrobacterium-mediated method to obtain functional complementary transgenic rice materials.Through molecular identification and phenotypic observation,it was found that the seed lengths of transgenic plants with restored expression of OsGT75 were also restored.