Improving Rice Salt and Drought Tolerance

Background: Salinity and drought stress are a major and global detriment to agricultural production. Their negative impact on crop production is exacerbated by sensitivity of major crops such as wheat and rice, a growing human population and climate change. For both salt and drought stress, the manipulation at the transcript level of single transporter genes in rice has shown that its tolerance can be significantly improved in this way. This includes altering expression of K+ transporters such as TPKs and AKTs and Na+ transporters such as NHXs and HKTs. However, the multigenic nature of salt and drought stress means that the expression of multiple transporters needs altering to optimise stress resistance. Such ‘stacking’ or ‘pyramiding’ of traits has hardly been attempted in rice abiotic stress.

Work plan and aims: This project envisages combining the positive effects that were observed by the manipulation of single genes to further improve salt and drought tolerance in rice. We will focus initially on genes for which transgenics are already available in the lab (vacuolar channels TPKa and TPKb, the K+ uptake and translocation systems AKT1 and SKOR and the Na+ transporter HKT2;1). Lines will be crossed and/or retransformed to generate multiple transgenics. Retransformation may include the use of tissue specific promoters. State of the art genome editing will also be applied to alter activity of specific genes. Using growth assays and mineral content analysis, lines will be assessed for synergistic phenotypes regarding tolerance to salt and drought stress.