ISHS Acta Horticulturae 381: International Symposium on Natural Phenols in Plant Resistance
THE USE OF ANTISENSE TECHNOLOGY TO MODIFY CONDENSED TANNIN ACCUMULATION IN TRANSGENIC LOTUS CORNICULATUS |
| Authors: | M.P. Robbins, P. Morris, T.R. Carron |
| Abstract:
We are interested in trying to understand the biological significance of phenylpropanoid end products in forage crop species. The experimental approach that we have selected is to attempt to modify flavonoid and polyphenolic metabolism in a readily transformable forage legume, Lotus corniculatus, using sense and antisense gene constructs. We report here some results analysing the effect of the introduction of a heterologous dihydroflavonol reductase (DFR) gene construct in transgenic root cultures and in regenerated Lotus plants. In particular we report results from two antisense lines (RFD38, RFD28) and two corresponding control lines (C26, C5). Both RFD38 and RFD28 root cultures accumulated lower levels of condensed tannins when compared with control lines. On acid hydrolysis, tannin polymers from RFD38 and RFD28 showed increased levels of procyanidin when compared with polymers from control lines, indicating the synthesis of less hydroxylated tannin molecules in antisense root cultures. In addition, regenerated plants from lines RFD38 and RFD28 showed decreased tannin levels in leaves and stems when compared with control material. However, although RFD28 root cultures showed consistently lower levels of tannin accumulation through successive subculture and through a growth curve in liquid culture, this line in contrast to other antisense lines examined did not appear to contain any detectable antisense gene or antisense transcript. We provide some speculations for the antisense phenotype noted with RFD28. | |
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