Evaluation of Novel Input Output Traits in Sorghum through Biotechnology

Sorghum (Sorghum bicolor (L.) Moench) is an important source for food, feed, and possesses many agronomic attributes attractive for a biofuels feedstock. A warm season crop originating from the semi-arid tropics, sorghum is relatively susceptible to both cold and freezing stress. Enhancing the ability of sorghum to tolerate cold and freezing offers a route to expand the acreage for production, and provides a potential drought avoidance strategy during flowering, an important parameter for protection of yield. Targeted perturbation of the signal transduction pathway, that is triggered by exposure to abiotic stress in plants, has been demonstrated in model systems as an avenue to augment tolerance. Calcium-dependent protein kinases (CDPKs) are key players in a plant’s response to environmental assaults. To test the impact of modulating CDPK activity in sorghum as a means to enhance abiotic stress tolerance, we introduced a constitutively expressed rice CDPK-7 (OsCDPK-7) gene construct. Sorghum transformants carrying this cassette displayed lesions on their leaves and up-regulation of a number of pathogen related proteins, along with transcripts linked to photosynthesis. These results demonstrate that modulating the Ca signaling cascade in planta via constitutively expressed CDPK can lead to off-target effects likely due to the broadly integrated nature of these enzymes in signaling.