Adapting rice to rising atmospheric carbon dioxide: A preliminary GMO approach to maintain nutritional integrity

Although there is extensive evidence that rising atmospheric carbon dioxide concentration, [CO2] can stimulate rice yields, such increases are also associated with a ubiquitous decline in nutrition, including protein, iron (Fe) and zinc (Zn). To determine the basis for these declines, we used gmo rice line pairs to test and compare the quantitative and qualitative metrics relative to their non-gmo counterparts at elevated [CO2] in situ. The gmo / non-gmo paired comparisons were associated with two phenological / metabolic characteristics associated with nutritional integrity: (1) an enlarged root system and (2) enhanced nitrate absorption. The two gmo lines showed a significantly higher percent stimulation of seed yield relative to their paired non-gmo cultivar at elevated [CO2]. However, relative to their non-gmo counterparts, leaf nitrogen and brown rice protein were not significantly reduced. In addition, the enlarged root system gmo line showed no decline in Fe and Zn at elevated [CO2]. While these findings are preliminary, they provide insight into specific traits associated with [CO2] induced declines in nutrition and could be fundamental in selecting and breeding qualitative and quantitative responses of global rice to maintain yield increases and nutritional integrity in response to projected increases in atmospheric [CO2].