Developing Climate Resilient Crops Using Stress-Associated Proteins, SAP10 and SAP13, for Providing Tolerance to Multiple Abiotic Stresses.

Abiotic stresses including drought, heat, salinity, and heavy metal toxicity as a result of climate change have far-reaching implications for global food security and already substantially impact agricultural production worldwide. To increase crop productivity for meeting the global food demand, it is imperative to understand the underlying molecular and biochemical mechanisms for developing crops resistant to multiple abiotic stresses. We have characterized the members of Stress-Associated Proteins (SAP) gene family in plants for their roles in providing tolerance to multiple abiotic stresses. The SAPs contain either A20 or AN1 or both A20/AN1 with extra Cys2-His2 RING zinc finger domains at the N- or C-terminal. Overexpression of SAP10 and SAP13 in Arabidopsis provided strong tolerance to multiple abiotic stresses such as salt, drought, heat, and various toxic metals including zinc, cadmium, arsenic, nickel and manganese, without causing a significant difference in metals accumulation except Zn. These plants attained significantly higher biomass and longer roots as compared to wild type plants under the stress condition in greenhouse conditionsHowever, the mode of action of this SAP member in providing tolerance to multiple abiotic stresses is largely unknown. We hypothesized that the expression of SAP genes might be regulated through the interaction of cis-elements present in the SAP gene promoters with abiotic stress related trans factors via protein-DNA interactions under different abiotic stresses. Through yeast one hybrid assay, we have proved this hypothesis and identified several transcription factors such as DREB, ERE, ZIP, HSE etc that are interacting with the AtSAP13 promoter. . Results from Arabidopsis were translated into Brassica juncea and when grown in greenhouse, transgenic brassica plants showed strong tolerance to multiple abiotic stresses including drought, salt and heavy metals. These results showed that members of the SAP family have the potential to be used for developing 'climate resilient crops' to ensure global food security.