Cloning Of The Gene Responsible For Rice Fragrance

Rice aroma is quite popular to people, so that fragrance has become one of the important eating qualities in rice. Among the 100 volatile flavor components, 2-acetyl-1-pyrroline (2AP) has been proved to render rice fragrance. It has been reported that a single recessive gene (fgr) located between RG1 and RG28 on chromosome 8 is responsible for this fragrant trait. Our initial mapping efforts with SSR markers not only confirmed the previous mapping result, but also narrow down the fgr locus between RM8264 and RM3459 with the physical distance of ~800 kb. The fgr region was then saturated with high-density markers developed by exploiting sequence diversities between indica and japonica rice subspecies. After fine mapping with segregant populations consisting of totally 2,891 individuals, the fgr locus was restricted into an interval L04 /L06, which is corresponding to 62kb in indica and just 35kb in japonica rice subspecies, respectively. Three annotated genes, encoding eukaryotic-type carbonic anhydrase (Cah), 3-methylcrotonyl-CoA carboxylase beta chain (Mccc2), and betaine aldehyde dehydrogenase (Badh2), shared by both the indica and japonica subspecies were therefore regarded as the Fgr candidate genes. The three predicted genes, containing intact promoters, coding regions, and 3'-untranslated regions, were isolated from the non-fragrant rice cv.'Nanjing 11'BAC library and transformed into the fragrant rice receptor'Wuxiangjing'for complementary test. No or very low 2AP contents were...