DOI: 10.3724/SP.J.1006.2017.01499

Acta Agronomica Sinica (作物学报) 2017/43:10 PP.1499-1506

Molecular Genetic Characteristics of Fragrance in a New Fragrant Rice Varie-ty Yuhui 2103

A major component 2-acetyl-1-pyrroline (2AP) in fragrance is one of the important indices of high-quality rice, however, the biosynthetic pathway of 2AP has not been demonstrated clearly. The betaine aldehyde dehydrogenase 2 (BADH2) is considered to be closely related to 2AP biosynthesis. In this study, three mutations in Badh2 gene were screened from thirty rice varieties and a new fragrant rice variety Yuhui 2103 was discovered. The new variety has no mutation in the coding region of Badh2 gene and the Badh2 allele of Yuhui 2103 can complement the defect of the badh2-E7 allele in Yixiang 1B. From crosses between Yuhui 2103 and non-fragrant varieties the segregating ratios of F2 fragrant to non-fragrant individuals were 9:7, while from crosses between Yuhui 2103 and fragrant varieties the segregating ratios of F2 fragrant to non-fragrant individuals were 7:9, indicating that fragrance of Yuhui 2103 is not controlled by only one gene. Furthermore, expression patterns of genes involved in 2AP biosynthesis were examined by the quantitative real-time PCR (qRT-PCR) in Nipponbare, Yuhui 2103, and Yixiang 1B. There was no significant difference in transcription level of Badh2 in Nipponbare and Yuhui 2103, however, the transcription level of Badh2 in Yixiang 1B was unexpectedly high. The expression levels of most of the genes involved in proline and glutamatic acid metabolism were significantly higher in Yixiang 1B than that in Nipponbare and Yuhui 2103. It is proposed that 2AP biosynthesis in Yixiang 1B is both influenced by Badh2 and the genes involved in proline and glutamatic acid metabolism, however, there is no necessary relationship between these genes and the fragrance of Yuhui 2103. The novel genetic characters of Yuhui 2103 may bring new breakthrough to the study of fragrance formation mechanism in rice.

Key words:Fragrant rice,2-Acetyl-1-pyrroline,Proline,Glutamatic acid,Badh2,Genetic characteristics

ReleaseDate:2017-12-07 14:03:30

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