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


CONCLUSIONS
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.
Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, Sichuan University, Chengdu 610064, PR China. niu_xiangli@163.com
Xiangli
X
Niu
Wei
W
Tang
Weizao
W
Huang
Guangjun
G
Ren
Qilin
Q
Wang
Di
D
Luo
Yingyong
Y
Xiao
Shimei
S
Yang
Feng
F
Wang
Bao-Rong
BR
Lu
Fangyuan
F
Gao
Tiegang
T
Lu
Yongsheng
Y
Liu
D000483:Alleles; D002681:China; D020090:Chromosome Segregation; D018556:Crops, Agricultural / Q000254:growth & development; D015536:Down-Regulation / Q000235:genetics*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018525:Germination; D009711:Nucleotides / Q000235:genetics; D009812:Odorants; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011758:Pyrroles / Q000378:metabolism*; D034622:RNA Interference; D036226:Seedlings / Q000254:growth & development
D009711:Nucleotides; D010940:Plant Proteins; D011758:Pyrroles; C426303:2-acetyl-1-pyrroline