Regulation Of Lignin Biosynthesis By OsSHN1and OsMYB48in Rice

Phenylpropanoid pathway is one of the most important secondary metabolite pathways in plants, and it is responsible for the biosynthesis of many kinds of products. Furthermore, lignin as an important metabolite, which has crucial impacts on agriculture, industry and the environment. However, there is little study about lignin regulation on rice. Here we report the characterization of the OsSHN1, a gene of ERF family in rice, and a MYB transcription factor. The main results are as follows:1. We have shown that overexpression of OsSHN1results in a reduction of the expression of lignin biosynthetic genes. In marked contrast, many genes that involved in lignin monomer biosynthesis were induced expression in the RNAi lines than the wild type ZH11.2. Fresh hand-cut sections of rice culms from ZH11wild type and RNAi line plants, phloroglucinol staining of lignin show that the lignin deposition in RNAi line plants was richer than the wild type ZH11. Furthermore, the RNAi plants showed an additional increase of lignin content in respect to wild-type by acetyl bromide method.3. Further study using the EMS A experiment demonstrated that OsSHN1was able to physically bind to the GCC-box in the promoter of the lignin biosynthetic gene OsCAD2.4. Our findings indicate that relative transcript accumulation of lignin biosynthetic genes in OsMYB48overexpression plants with respect to wild type ZH11, and OsMYB48expression level is induced under ABA stress treatment inordinately; Fresh hand-cut sections of rice culms from ZH11wild type and OsMYB48overexpression plants, phloroglucinol staining of lignin show that the lignin deposition in overexpression plants was more rich than the ZH11wild type.