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Salicylates/Jasmonates Regulate Lignin Biosynthesis In Rice

Posted on:2015-06-06Degree:MasterType:Thesis
Country:ChinaCandidate:L ZouFull Text:PDF
GTID:2180330452954407Subject:Biochemistry and Molecular Biology
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Lignin, the most abundant component of secondary cell wall, is an important product of phenylpropanoid-derived polymer. As a crucial plant metabolite, it is essential for providing mechanical strength, increasing pathogen defense and water transport in vascular plants. Jasmonate (JA) and salicylate (SA) are two important endogenous signal molecules in pathogen defense pathway. They play key roles in the process of the resistance of pathogenic microorganisms in plants. We supposed SA and JA can facilitate lignin biosynthesis and provide an efficient protection from pathogen. Here, we study the mechanism of that SA and JA regulate lignin biosynthesis pathway through bioinformation, molecular, cell and metabolism level. The main results are as follows:1. The regulation of SA induced lignin biosynthesisInduced expression analysis showed that defense related transcription factor WRKY45and lignin genes can be induced by SA at the same time. Meanwhile, the expression of lignin genes were followed after WRKY45. The root and leaf sheath, from wild type and300μM SA treated ZH11, was used for histochemical staining and the result demonstrated SA can increase lignin biosynthesis in root. The relative expression of lignin genes was determined in overexpression and knock-out lines. In WRKY45overexpression lines lignin genes4CL5and CAD2were upregulated and4CL5change trend was special consistant with WRKY45. In WRKY45knock-out lines4CL5was down-regulated but not4CL3and CAD2. The change of4CL5was agreed with WRKY45, so we supposed WRKY45can bind on the promoter of4CL5directly.2.The regulation of JA induced lignin biosynthesisNtMYBJSl is a methyl jasmonate-dependent regulator of phenylpropanoid-conjugate biosynthesis in tobacco. We found its homologous genes in rice and confirmed candicate transcription factor by analysis of expression, coexpression, induced expression, co-induced expression and promoter. The results indicated that JA may regulate lignin biosynthesis through MYB transcription factor OsMYBL,OsMYB13,OsMYB14,OsMYB19and OsMYB58. To confirm these MYBs can bind on lignin genes, we build yeast one hybrid vectors, the CDS of MYB genes and the promoter of lignin genes. The result of yeast one hybrid is:OsMYB58, OsMYB19, OsMYB13and OsMYB4can act with Os4CL3and Os4CL5but the action competence are in turn weakens. The overexpression and RNAi vector of candicate MYBs had been builded and transgened and most of them had transgene plants.
Keywords/Search Tags:Jasmonate, salicylate, lignin, transcription factor, regulate
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