Crop Biotech Update

Functional Characterization of OsSAPK2 Using CRISPR-Cas9

June 14, 2017

SNF 1-Related Protein Kinase 2 (SnRK2) is a family of kinases which regulates hyper-osmotic stress signaling and abscisic acid-dependent development in plants. In rice, the osmotic stress/ABA–activated protein kinase 2 (SAPK2) is the main mediator of ABA signaling. However, it has not been fully studied. Dengji Lou from the Chinese Academy of Sciences studied the function of OsSAPK2 using loss-of-function mutants produced through CRISPR-Cas9 system.

The OsSAPK2 expression level was found to be strongly upregulated by drought, high-salinity, and polyethylene glycol (PEG) treatments. The sapk2 mutants exhibited an ABA-insensitive phenotype, suggesting that OsSAPK2's role is related to ABA-mediated seed dormancy. The ossapk2 mutants were also more sensitive to drought stress and reactive oxygen species, indicating its importance in rice drought responses.

Further analysis revealed that OsSAPK2 increased drought tolerance in rice by reducing water loss by promoting stomatal closure, and upregulating the expression of stress-response genes and inducing the expression of antioxidant enzyme genes to promote ROS-scavenging abilities.

These results imply that OsSAPK2 is a potential candidate gene for future crop improvement.

For more on the study, read the article in Frontiers in Plant Science.