Quality of the rice grain is determined mainly by starch and protein contents of the endosperm. In this thesis, the analyses of four genes involved in the regulation of development of rice grain... Show moreQuality of the rice grain is determined mainly by starch and protein contents of the endosperm. In this thesis, the analyses of four genes involved in the regulation of development of rice grain and floret are presented. Two CCCH type zinc finger proteins, OsGZF1 and OsGZF2, were identified as novel transcription factors for GluB-1, one of the major seed-storage protein genes. Both of them exhibited negative effects on the GluB-1 promoter in transient expression assays. In a collection of rice mutants, two Tos17 transposon lines were identified showing open-staying florets and abnormal seed development. The mutant gene was identified as OsJAR1 and was shown to encode a jasmonic acid-amino acid synthetase. Next, we identified the potassium antiporter OsCHX14 as one of the downstream genes of OsJAR1. Yeast complementation assays confirmed that OsCHX14 is capable of effluxing K+ outside of cells. Its potential role in regulating of floret closure in rice was discussed. Show less
