OsGF14b is involved in regulating coarse root and fine root biomass partitioning in response to elevated [CO₂] in rice

Elevated [CO2] can increase rice biomass and yield, but the degree of this increase varies substantially among cultivars. Little is known about the gene loci involved in the acclimation and adaptation to elevated [CO2] in rice. Here, we report on a T-DNA insertion mutant in japonica rice exhibiting a significantly enhanced response to elevated [CO2] compared with the wild type (WT). The root biomass response of the mutant was higher than that of the WT, and this manifested in the number of adventitious roots, the average diameter of roots, and total root length. Furthermore, coarse roots (>0.6 mm) and thin lateral roots (<0.2 mm) were more responsive to elevated [CO2] in the mutant. When exposed to lower light intensity, however, the response of the mutant to elevated [CO2] was not superior to that of the WT, indicating that the high response of the mutant under elevated [CO2] was dependent on light intensity. The T-DNA insertion site was located in the promoter region of the OsGF14b gene, and insertion resulted in a significant decrease in OsGF14b expression. Our results indicate that knockout of OsGF14b may improve the response to elevated [CO2] in rice by enhancing carbon allocation to coarse roots and to fine lateral roots.