Adapting Rice to Atmospheric Carbon Dioxide: A GMO approach to yield enhancement and nutritional integrity.

There is extensive evidence that rising atmospheric carbon dioxide concentration, [CO ] can stimulate rice yields. However, such increases are 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 lines to test and compare the quantitative and qualitative metrics relative to their non-gmo counterparts at elevated [CO ] in situ. The gmo / non-gmo paired comparisons were associated with three phenological / metabolomic characteristics: (1) increased stomatal conductance, (2) an enlarged root system, and (3) enhanced nitrate absorption. All gmo lines showed a significantly higher percent stimulation of seed yield relative to their paired non-gmo cultivar at elevated [CO ]. Qualitatively, relative to non-gmos, leaf nitrogen and brown rice protein were not significantly reduced and for (1) and (2) the gmo lines showed no decline in Fe and Zn with elevated [CO ]. These findings do not, de facto, represent a gmo “solution” to [CO ] induced nutritional decay; however they provide the first evidence that gmo lines related to specific traits could be fundamental in selecting qualitative and quantitative responses of global rice to maintain yield and nutritional integrity in response to projected increases in atmospheric [CO ].