Potassium Transporter OsHAK1 Regulates Responses to Drought Stress in Rice

Drought is one of the environmental factors that severely restrict plant distribution and crop production. Previous studies have reported that the high-affinity potassium transporter OsHAK1 plays important roles in potassium acquisition and translocation in rice. However, knowledge on the regulatory roles of OsHAK1 in drought stress is limited. The team of Guang Chen from China National Rice Research Institute now aims to elucidate its role in drought stress regulation.

The transcript levels of OsHAK1 were found to be elevated by water deficit in roots and shoots. Under drought conditions, the OsHAK1 knockout mutants (KO) exhibited lower drought tolerance and displayed stunted growth. The OsHAK1 overexpression seedlings (Ox) showed better tolerance to drought stress than wild types. Further analysis revealed that OsHAK1 acts as a positive regulator of the expression of stress-responsive genes as well as of two well-known rice channel genes, OsTPKb and OsAKT1, involved in potassium homeostasis and stress responses in the transgenic plants under dehydration.

Most importantly, OsHAK1-Ox plants displayed enhanced drought tolerance at the reproductive stage, resulting in 35% more grain yield than wild types under drought conditions. This study shows that OsHAK1 can be considered in molecular breeding for improvement of drought tolerance in rice.

For more information, read the article in Frontiers in Plant Science.