Evidence of starch accumulation in tobacco Bright Yellow (TBY-2) cells in the presence of auxin

Abstract

Tobacco Bright Yellow (TBY-2) cell suspension is known to produce starch when cultured in a medium supplemented with cytokinin or in a hormone-free medium. Unexpectedly, TBY-2 cells continuously cultivated in the presence of auxin alone were also able to accumulate starch at the beginning of a stationary growth phase, with a yield of 9.22% ± 0.68%. 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 of amylopectin over amylose of 2.7, which was also linked to typical small granules (1.4 µm). According to our preliminary results, this plant cell suspension could yield a low-cost, amylopectin-rich starch — which is needed in the food industry to produce edible film or bioplastic — without being impacted by climate or seasonal weather changes.