SbbHLH1 And SbRAP Transcription Factors In Lignin Biosynthesis Metabolism Of Sorghum Bicolor

The international oil market depressed does not mean that the energy crisis was eased in the past two years and traditional fossil fuels such as coal, oil will run out. So discovering renewable, clean and lower CO2 emissiongs new energy become the urgent problem that the world need to face. Ethanol has the advantage that the green environmental protection, renewable, so it is right of a new generation of energy. The technology using lignocelluloses as ethanol production material is increasingly valued.Lignocellulose has complex structure, which containedcellulose, hemicellulose and lignin. Lignocellulose is difficult to be degraded due to its complex structure, which is still the biggest obstacle for the conversion of biomass feedstocks to bioenergy. Approaches of genetic engineering changes in lignin synthesis pathway and major gene expression to regulate lignin biosynthesis, reduce the lignin content, increase the content of cellulose has become a modified way for bioethanol production technology. In this work, we try to understand the role and mechanism of the twotranscription factors genes, SbbHLHl and SbRAP, to create conditions for the use of genetic engineering technology reducing lignin content in the lignin metabolism.We suggest SbbHLHl can interact with WD40-repeat protein or MYB protein and form protein complex after consulting lots of papers and referring to the results of researchers. We construct the yeast two hybrid vectors, and use yeast two hybrid technology to screening the protein interacted with SbbHLHl from lignin and anthocyanins biosynthesis and regulation genes. We discover that SbbHLHl can interact with AtTT8 (bHLH), AtPAP 1 (MYB75), AtPAP2 (MYB90) at different degree but not interact with two kinds of WD40-repeats protein, AtTTGl and AtAN11, which suggests SbbHLHl can not interact with WD40-repeats protein but interact with bHLH and MYB proteins. We know AtTT8, AtPAP1/AtPAP2, AtTTG1 can make up bHLH-MYB-WD40 protein complex, the most critical protein complex for regulating anthocyanins biosynthesis, which consists with the result of overexpressing SbbHLH1 in Arabidopsis thaliana caused the expression of flavonoids biosynthesis genes inhibited. AtPAP1(MYB75) plays an inhibiting role in lignin biosynthesis pathway and overexpressing AtPAP1 in Arabidopsis thaliana caused the content of lignin reducing. We still can not understand the relation between SbbHLH1 with AtPAP1, which need to be studied.SbRAP (belongs to AP2/ERF) is transcription factor in Sorghum bicolor and overexpressing of SbRAP in Arabidopsis thaliana caused the content of lignin reducing and caused the expression of several lignin biosynthesis genes inhibited. So SbRAP is also an inhibitor for lignin biosynthesis pathway, and the mechanism of SbRAP need to be elucidated.