Research article

RNAi-directed downregulation of OsBADH2 results in aroma (2-acetyl-1-pyrroline) production in rice (Oryza sativa L.)

Xiangli Niu^{* 1,2} , Wei Tang^{* 1,2} , Weizao Huang^{* 3} , Guangjun Ren³ , Qilin Wang^1,2 , Di Luo^1,2 , Yingyong Xiao^1,2 , Shimei Yang^1,2 , Feng Wang⁴ , Bao-Rong Lu⁵ , Fangyuan Gao³ , Tiegang Lu⁶ and Yongsheng Liu^1,2

¹Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, Sichuan University, Chengdu 610064, PR China

²State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, PR China

³Institute of Crop Research, Sichuan Academy of Agricultural Sciences, Chengdu 610066, PR China

⁴Biotechnology Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003, PR China

⁵Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, PR China

⁶Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China

author email corresponding author email* Contributed equally

BMC Plant Biology 2008, 8:100doi:10.1186/1471-2229-8-100

Published:	8 October 2008

Abstract

Background

Aromatic rice is popular worldwide because of its characteristic fragrance. Genetic studies and physical fine mapping reveal that a candidate gene (fgr/OsBADH2) homologous to betaine aldehyde dehydrogenase is responsible for aroma metabolism in fragrant rice varieties, but the direct evidence demonstrating the functions of OsBADH2 is lacking. To elucidate the physiological roles of OsBADH2, sequencing approach and RNA interference (RNAi) technique were employed to analyze allelic variation and functions of OsBADH2 gene in aroma production. Semi-quantitative, real-time reverse transcription-polymerase chain reaction (RT-PCR), as well as gas chromatography-mass spectrometry (GC-MS) were conducted to determine the expression levels of OsBADH2 and the fragrant compound in wild type and transgenic OsBADH2-RNAi repression lines, respectively.

Results

The results showed that multiple mutations identical to fgr allele occur in the 13 fragrant rice accessions across China; OsBADH2 is expressed constitutively, with less expression abundance in mature roots; the disrupted OsBADH2 by RNA interference leads to significantly increased 2-acetyl-1-pyrroline production.

Conclusion

We have found that the altered expression levels of OsBADH2 gene influence aroma accumulation, and the prevalent aromatic allele probably has a single evolutionary origin.