Evidence of starch accumulation in TBY-2 cells in the presence of auxin

Tobacco cell suspension (TBY-2) is known to produce starch when cultured in medium supplemented with cytokinin or in hormone-free medium. Unexpectedly, TBY-2 cells, continuously cultivated on auxin alone, were also able to accumulate starch at the beginning of stationary growth phase with a yield of 9.22 ± 0.68 percent. This starch production was strongly correlated with a 25-fold increase in starch synthase activity. Moreover, this TBY-2 line was able to produce an amylopectin-rich starch with a ratio amylopectin over amylose of 2.7 which also linked to typical small granules (size around 1.4 µm). According to our preliminary results, this plant cell suspension could produce a low-cost amylopectin rich starch needed in the food industry for production of edible film or bioplastic without impacts from climate or season changes.

Oxidative burst and cell death induced by b-quercinin and zoospores of Phytophthora quercina in tobacco cell cultures

Mode of action of β-quercinin, a novel elicitin on tobacco cell suspension cultures (cvs. Bel B and Bel W3) was investigated by measuring the oxidative burst and cell death in these cell cultures. β-quercinin induced an oxidative burst comparable to that excited by zoospores from P. quercina. Adding superoxidedismutase, catalase and diphenyleneiodonium to elicited cell cultures, it could be demonstrated, that the induction of cell death in tobacco cell cultures is not correlated to the oxidative burst.