Understanding the role of the novel gene, SENSITIVE-TO-FREEZING10 (SFR10), in integrating freezing and light acclimation in plants

Improving crop resilience to stresses including freezing is a key challenge to agriculture in the face of an unpredictable climate. Cold acclimation allows plants to increase their freezing tolerance through a program of transcriptional and metabolic alterations in response to cool conditions before the onset of winter. The interaction between light and cold acclimation has previously been studied, with light appearing to be important for establishing freezing/cold tolerance especially under long day conditions. Specifically, parameters linked to photosynthetic electron transport are affected by light levels during cold acclimation, and elevated light intensities at normal growth temperatures may induce freezing tolerance. Light also influences the expression level of cold-regulated genes, however, the molecular basis of the interaction between light and cold acclimation is poorly understood. We have shown the gene SENSITIVE-TO-FREEZING 10 (SFR10) encodes a chloroplast-located protein that is necessary for full cold acclimation to freezing stress in Arabidopsis and photosynthetic acclimation to high light levels (unpublished data). Homologues exist across a range of monocot and dicot species, making SFR10 a strong candidate for improving crop productivity and stress resilience. This project will use complementary approaches to understand the mechanistic basis of SFR10's effect whilst revealing its molecular evolution and mutations responsible for increased freezing tolerance. The project will begin with a thorough characterisation of SFR10 loss- and gain-of-function Arabidopsis plants for cold-acclimation-induced freezing tolerance, photosynthetic acclimation, productivity and metabolite content under normal and stress conditions as well as examining the localisation of GFP-tagged SFR10 in response to cold and high light. Preliminary examination of the SFR10 protein sequence reveals a potential DNA-binding domain so it is possible SFR10 regulates the expression of other genes. The candidate will seek to identify chloroplast-localised DNA and protein interactors of SFR10 and will analyse and validate existing RNAseq data to identify SFR10-responsive transcripts. Further to this, we will perform a complementary evolutionary analysis of hundreds of SFR10 homologs from a wide range of angiosperms hailing from different climates, available in GenBank, within the framework of phylogenetic analyses for positive selection. This will allow us to pinpoint potential amino acid switches within the SFR10 protein responsible for increased freezing tolerance. SNPs encoding such amino acid switches will be queried empirically by complementing a complete loss of function sfr10 mutant with modified SFR10 sequences and if time allows, by creating CRISPR-Cas modified Brassica napus, and testing them for freezing tolerance and light acclimation.