Young Keun Cheong

Enhanced anthocyanin accumulation confers increased growth performance in plants under low nitrate and high salt stress conditions owing to active modulation of nitrate metabolism

Plants require nitrogen (N) for growth and development. However, they are frequently exposed to conditions of nitrogen deficiency. In addition, anthocyanin accumulation is induced under salt stress and nitrate deficiency. To date, most studies have revealed that nitrate deficiency under high sucrose levels induce high levels of anthocyanin accumulation in plants. However, the underlying mechanisms remain unclear. Under nitrate-starved conditions, plant growth rapidly worsens and cells eventually die. In addition, plants are severely affected by salt exposure. Therefore, in this study, we determined whether increased levels of anthocyanin could improve plant growth under salt stress and nitrate-starved conditions. We used PAP1-D/fls1ko and ttg1 plants which have a perturbed anthocyanin biosynthesis pathway to explore the role of anthocyanin in plant adaptation to nitrate-deficient conditions and salt stress. Our results demonstrate that high anthocyanin accumulation in PAP1-D/fls1ko plants confers enhanced tolerance to nitrate-deficient conditions combined with high salinity. PAP1-D/fls1ko plants appeared to use absorbed nitrate efficiently during the nitrate reduction process. In addition, nitrate-related genes such as NRT1.1, NiA1 and NiA2 were upregulated in the PAP1-D/fls1ko plants. On the basis of these findings, it can be concluded that high anthocyanin accumulation helps plants to cope with salt stress under nitrate-deficient conditions via the effective utilization of nitrate metabolism.

Comparison of blood glucose levels and allergic responses on treatment with six wheat cultivars

Allergies and indigestion problems have increased in our society with increasing wheat consumption. Among wheat proteins, omega-5 gliadins (ω5-gliadins) and high molecular weight (HMW)-glutenin are known to be some of the major factors responsible for an allergic response and indigestion. Certain low molecular weight (LMW)-glutenin subunits are also able to promote local inflammation, and share common epitopes with ω5-gliadins. It is known that different wheat cultivars have different combinations of HMW- and LMW-glutenins. We investigated the relationship between the composition of LMW-glutenins and the degree of allergic response or indigestion. The extent of allergic reaction and indigestion characteristics in response to six different wheat cultivars were compared. Patterns of the change of blood glucose level with time, which were employed to measure the indigestion, were quite different, depending on the type of wheat cultivars. The extent of allergic response, as measured with the histamine and IgE levels, was also quite different, depending on the type of wheat cultivars. In addition, the extents were not correlated with patterns of LMW-glutenin DNA and HMW/LMW glutenin protein of various wheat cultivars. The results from the present study suggest that some more other factors, together with factors studied above, need to be considered to better explain the physiological phenomena of variation in blood glucose level and allergic response.