A R2R3-MYB transcription factor, GmMYB12B2, affects the expression levels of flavonoid biosynthesis genes encoding key enzymes in transgenic Arabidopsis plants.
Isoflavones play diverse roles in plant-microbe interactions and are potentially important for human nutrition and health. To study the regulation of isoflavonoid synthesis in soybean, the R2R3-MYB transcription factor GmMYB12B2 was isolated and characterized. Yeast expression experiments demonstrated that GmMYB12B2 showed transcriptional activity. GmMYB12B2 was localized in the nucleus when it was transiently expressed in onion epidermal cells. Real-time quantitative PCR analysis revealed that GmMYB12B2 transcription was increased in roots and mature seeds compared with other organs. The gene expression level in immature embryos was consistent with the accumulation of isoflavones. CHS8 is a key enzyme in plant flavonoid biosynthesis. Transient expression experiments in soybean calli demonstrated that CHS8 was regulated by GmMYB12B2 and produced more fluorescence. The expression levels of some key enzymes in flavonoid biosynthesis were examined in transgenic Arabidopsis lines. The results showed that the expression levels of PAL1, CHS and FLS in transgenic plants were significantly higher than those in wild type plants. However, the expression level of DFR was lower, and the expression levels of CHI, F3H and F3'H were the same in all lines. GmMYB12B2 expression caused a constitutive increase in the accumulation of flavonoids in transgenic Arabidopsis lines compared with wild type plants.
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
Xiao-Wei
XW
Li
Jing-Wen
JW
Li
Ying
Y
Zhai
Yan
Y
Zhao
Xu
X
Zhao
Hai-Jun
HJ
Zhang
Lian-Tai
LT
Su
Ying
Y
Wang
Qing-Yu
QY
Wang
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics; D044950:Flavanones / Q000235:genetics / Q000378:metabolism; D005419:Flavonoids / Q000096:biosynthesis* / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D007529:Isoflavones / Q000378:metabolism; D008969:Molecular Sequence Data; D019697:Onions / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics; D013025:Glycine max / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015003:Yeasts / Q000235:genetics
D029681:Arabidopsis Proteins; D044950:Flavanones; D005419:Flavonoids; D007529:Isoflavones; D014157:Transcription Factors; D010088:Oxidoreductases; D000217:Acyltransferases; C491135:AT5G13930 protein, Arabidopsis; C005273:naringenin
CHI; CHS; Chalcone isomerase; Chalcone synthase; DAP; DFR; Days after pollination; Dihydroflavonol 4-reductase; Expression pattern; F3H; F3′H; Flavanone 3-hydroxylase; Flavonoid; Flavonoid 3-hydroxylase; HPLC; High-performance liquid chromatography; IFS; Isoflavone synthase; Isoflavones; MYB transcription factors; PAL; Phenylalanine ammonia lyase; Quantitative real-time PCR; Semi-quantitative reverse transcription polymerase chain reaction; Sg7; SqRT-PCR; Subgroup 7; TFs; Transcription factors; Transcriptional activation; Transgenic Arabidopsis thaliana; qRT-PCR