Functional studies and genome editing for improving salinity tolerance in rice
Résumé
Soil salinity is a growing environmental constraint on agricultural production worldwide, exacerbated by climate change and the increased use of irrigation. In order to improve the tolerance of cultivated plants to this constraint, quantitative loci (QTL) have been sought, revealing the potential of Na + transporter genes from the HKT family for breeders as major QTLs for salt tolerance in a wide variety of crops 1,2 . In cereals, the HKT1;5 gene is the most widely used by breeders to confer higher salinity tolerance. HKT1;5 encodes a Na + selective transporter that retrieves Na + from the xylem sap into surrounding parenchyma cells, thereby protecting the leaf tissues from Na + toxicity. In several HKT genes from cereals including HKT1;5 from rice, we have initiated an evaluation of related halophyte orthologs and variants derived from natural diversity with the aim of identifying additional sequences linked to salt tolerance 3,4 . Our approach combines functional studies using electrophysiology and structural modeling to identify variants with the most efficient transport capabilities under high salinity conditions, and thus the sequences associated with them. Next, genome editing in the cereal model plant rice, facilitated by the CRISPR technology, is used to express the selected variants and evaluate their potential for improving salt tolerance.