[SEMINAR] Tailoring DELLA repressors for increased salt tolerance

Title: Tailoring DELLA repressors for increased salt tolerance

Speaker: Salomé Prat
[08193 Cerdanyola (Barcelona) | salome.prat@cragenomica.es]

From: Centre for Research in Agricultural Genomics (CRAG)

Abstract: DELLAs repress growth by directly binding several factors with a role in transcriptional activation of auxin and cell elongation genes and sequestering them in an inactive form unable to bind to DNA.  However, these repressors act as well as co-activators of other transcriptional regulators to the activation of ABA signaling and ROS scavengers thus enhancing tolerance to salt stress.  DELLAs accumulate under salinity conditions and their increased abundance underlies the trade-off between stress tolerance and suppressed growth.  We here searched to uncouple these two effects by screening for single mutations that impaired interaction of GAI and Arabidopsis PIF4.  Notably, all identified mutants mapped into a 20 amino acid segment, hence identifying this region as a PIF4 docking domain. Amino acidic substitutions in this region had little impact on the binding of other protein partners, proving that it functions as a specific PIF4 interaction domain. Over-expression of DELLAs with these substitutions leads in Arabidopsis and potato to significantly increased tolerance to salt, while has only a mild growth inhibition effect. CRISPR base edition of such residues emerges in consequence as a novel approach to increase crops salinity resistance without a penalty on growth.