Modification of lignin biosynthesis in transgenic Nicotiana through expression of an antisense O-methyltransferase gene from Populus
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- Dwivedi, U.N., Campbell, W.H., Yu, J. et al. Plant Mol Biol (1994) 26: 61. doi:10.1007/BF00039520
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An aspen lignin-specific O-methyltransferase (bi-OMT; S-adenosyl-l-methionine: caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase, EC 184.108.40.206) antisense sequence in the form of a synthetic gene containing the cauliflower mosaic virus 35S gene sequences for enhancer elements, promoter and terminator was stably integrated into the tobacco genome and inherited in transgenic plants with a normal phenotype. Leaves and stems of the transgenes expressed the antisense RNA and the endogenous tobacco bi-OMT mRNA was suppressed in the stems. Bi-OMT activity of stems was decreased by an average of 29% in the four transgenic plants analyzed. Chemical analysis of woody tissue of stems for lignin building units indicated a reduced content of syringyl units in most of the transgenic plants, which corresponds well with the reduced activity of bi-OMT. Transgenic plants with a suppressed level of syringyl units and a level of guaiacyl units similar to control plants were presumed to have lignins of distinctly different structure than control plants. We concluded that regulation of the level of bi-OMT expression by an antisense mechanism could be a useful tool for genetically engineering plants with modified lignin without altering normal growth and development.
Key wordsantisense inhibition aspen O-methyltransferase lignin biosynthesis transgenic tobacco
cinnamyl alcohol dehydrogenase
Populus tremuloides bi-OMT cDNA clone