Activity and Accumulation of Cell Division-Promoting Phenolics in Tobacco Tissue Cultures

Abstract

Dehydrodiconiferyl alcohol glucosides (DCGs) Candidates for such a non-adenyl metabolite are the cell division-promoting substances found in fractions isolated from hormone-autonomous Catharanthus roseus crown gall tumors by . These tumors, now also known to synthesize zeatin and ZR (18), were recently reinvestigated ( 16). The fractions isolated by Wood et al.(29) were shown to contain DCG4 isomers capable of replacing cytokinin in the promotion of tobacco pith growth in culture. The individual DCG isomers differed in their ability to stimulate proliferation with isomers A and B (differing only in the enantiomeric nature of the phenylpropanoid dimer) being the most active (5). The relatively inactive isomers D and E differed from A and B only with respect to the location of the glucose moiety, at the C-13 hydroxyl and C'-4 hydroxyl, respectively (5). Moreover, the active DCGs were found in quiescent tobacco pith tissue at low levels (approximately 0.05 yM) but at 20-to 50-fold higher levels in actively growing cultured pith tissue (5). Such results indicated that these naturally occurring, phenolic derivatives could stimulate cell division. To demonstrate that the purified DCGs were, in fact, responsible for the biological activity observed, DCG isomers A and B (hereafter referred to as DCG A + B) have been synthesized chemically and their activities reexamined. The results presented here indicate that synthetic DCG A + B possess cell division-promoting activity but do not share several other biological activities with the adenine-derived cytokinins. In addition, we show that the accumulation of DCG A and DCG B in cultured tobacco pith explants is 4Abbreviations: DCG, dehydrodiconiferyl alcohol glucoside;

Improvement of biomass through lignin modification

“…An alternative explanation is that perturbations in lignin biosynthesis affect the accumulation of some other derivatives of the phenylpropanoid pathway that are required for, or have direct or indirect deleterious effects on, normal plant growth and development. For example, in tobacco, dehydrodiconiferyl alcohol glucosides, lignan glycosides derived from coniferyl alcohol, were found to have a cytokinin-like ability to stimulate cell division (Teutonico et al, 1991). It is possible that, as a result of genetic engineering of the lignin biosynthetic pathway, reductions in coniferyl alcohol pools lead to deficiency of dehydrodiconiferyl alcohol glucosides and altered cell division.…”

Down‐regulation of Cinnamoyl‐CoA Reductase induces significant changes of lignin profiles in transgenic tobacco plants

“…The latter have been shown to be involved in signal transduction of cytokinin-mediated cell division (Teutonico et al, 1991). In addition, a decrease in CCR activity is accompanied by the accumulation of soluble phenolics (J.P. Biolley, personal communication).…”

Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase

“…This is an ambitious task for a cell wall-associated enzyme such as anionic peroxidase; however, many of the biologically active compounds in the plant do pass through the wall and coincidentally are metabolized by peroxidase. These compounds include H,O, (Tenhaken et al, 1995), IAA , dehydrodiconiferyl alcohol glucosides (Teutonico et al, 1991), and arachidonic acid (Garner, 1984). The altered activity of anionic peroxidase in transgenic plants could dramatically affect the concentration and mobility of any of these biologically active substances.…”