UC Davis

We have previously shown that overexpression of GSK3-like kinase 5 in rice (OsGSK5) was associated with higher starch accumulation and better growth under severe salinity stress. Short-term ¹⁴CO₂ feeding experiments suggested that OsGSK5 promoted higher flux to starch accumulation in the roots under this condition and that this mechanism may help to underscore the better growth characteristics observed. Here, we expand upon this hypothesis and consider (1) how OsGSK5 action could fit into a signaling model that integrates salinity stress to changes in starch metabolism, and (2) how this would facilitate whole plant physiological adaptations in source-to-sink partitioning. We also discuss additional functions of OsGSK5, necessary to support this adaptive mechanism.