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

面对变幻莫测的气候，提高作物对包括严寒在内的逆境的适应能力是农业面临的一项关键挑战。冷驯化允许植物通过一系列转录和代谢变化来提高它们的耐寒性，以应对冬季到来之前的寒冷条件。光和冷驯化之间的相互作用已经被研究过，光似乎对建立耐寒能力很重要，特别是在长日照条件下。具体地说，与光合作用电子传递有关的参数在低温驯化过程中受到光照水平的影响，正常生长温度下较高的光照强度可能会诱导植物耐寒。光也影响冷调节基因的表达水平，然而，光和冷驯化相互作用的分子基础还不清楚。我们已经证明了对冷冻敏感的基因10(SFr10)编码一种叶绿体定位的蛋白，这是拟南芥完全适应低温胁迫和光合作用适应高光胁迫所必需的(未发表的数据)。同源物存在于一系列单子叶和双子叶植物中，使SFr10成为提高作物生产力和抗逆性的有力候选者。该项目将使用互补的方法来了解SF10的S效应的机制基础，同时揭示其分子进化和导致耐寒性增强的突变。该项目将首先对SFr10功能丧失和功能获得的拟南芥植株在正常和胁迫条件下的耐寒性、光合作用驯化、生产力和代谢物含量进行彻底的表征，并研究GFP标记的SFr10在寒冷和强光下的定位。对SFr10蛋白序列的初步检测显示了一个潜在的DNA结合域，因此SFr10可能调节其他基因的表达。候选人将寻求确定SFr10的叶绿体定位的DNA和蛋白质相互作用因子，并将分析和验证现有的RNAseq数据，以确定SFr10响应的转录本。此外，我们将在正向选择的系统发育分析框架内，对来自不同气候的各种被子植物的数百个SFr10同源物进行互补进化分析。这将使我们能够准确定位SFr10蛋白中潜在的氨基酸开关，这些开关与提高耐寒性有关。编码这种氨基酸开关的SNPs将通过用修改的SFr10序列来补充完全丧失功能的SFr10突变体，如果时间允许的话，通过创造CRISPR-Cas改良的甘蓝型油菜，并测试它们的耐寒性和光照驯化来进行经验性的质疑。

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for full cold acclimation to freezing stress in Arabidopsis and photosynthetic acclimation to high light levels (unpublished data).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.