Signalling the way forward: Understanding plant adaption to environmental change

植物对非生物胁迫的反应是一系列有效的保护反应。环境扰动的关键信号事件和转录反应已被广泛报道。然而，在代谢水平上的反应还不太清楚。一个明显的例子是涉及脂质重塑的代谢应激反应。植物调节途径的脂肪酸合成，脂质组装和运输的重塑膜响应压力。例如，温度应激触发脂质依赖性信号级联（例如磷酸肌醇、鞘脂、二酰基甘油），其控制基因簇并激活适应。调节脂肪酸合成和去饱和的水平以维持膜功能，并且植物通过诱导的脂肪酶和酰基转移酶活性的网络进行血浆磷脂（磷酸胆碱）和类囊体半乳糖脂（例如单半乳糖基二酰基甘油）的复杂重塑。一些与适应相关的代谢变化会产生有毒代谢物（如游离脂肪酸），这些代谢物可以通过掺入三酰甘油来处理。细胞脂质体（细胞中脂质的总和）的这些变化共同使植物能够适应并在多变的气候中生存。尽管所有植物都具有重塑其细胞脂质体以响应非生物胁迫的能力，但不同物种和品种的能力往往不同。目前，我们对非生物胁迫的脂质反应的理解主要来自模式物种，如拟南芥，但现在有兴趣使用极端微生物物种，适应具有挑战性的气候，解剖植物脂质信号传导和重塑的机制。Eutrema salsugineum（“盐克雷斯”）对非生物胁迫（温度和盐度）具有很强的适应性。此外，作为芸苔属植物家族的一员，与拟南芥属植物关系密切，是研究植物抗逆性的重要平台。Eutrema的基因组已完全测序，并建立了转化方法。Eutrema和拟南芥基因组之间的相似性允许基因和它们的功能之间的直接比较，使得大多数为拟南芥开发的实验程序具有高度的适应性。该项目的主要目的是阐明应激诱导的脂质代谢的生化过程和功能意义。利用拟南芥和Eutrema，我们将专注于温度胁迫的机制。当前和预测的气候变异性对粮食生产具有关键影响，因此，在拟议工作中形成的基本认识将建立以知识为基础的战略，以解决作物温度弹性问题。

Plants respond to abiotic stress with a wide range of effective protective responses. Key signalling events and transcriptional responses to environmental perturbation have been widely reported. However, responses at the metabolic level are less well understood. One clear example is the metabolic stress response involving lipid remodelling. Plants regulate pathways of fatty acid synthesis, lipid assembly and trafficking for remodelling of membranes in response to stress. For instance, temperature stress triggers lipid-dependent signalling cascades (e.g. phosphoinositides, sphingolipids, diacylglycerol), which control gene clusters and activate adaption. Levels of fatty acid synthesis and desaturation are regulated to maintain membrane function and plants undertake complex remodelling of plasma phospholipids (phosphocholine) and thylakoid galactolipids (e.g. monogalactosyl diacylglycerol) via a network of induced lipase and acyltransferase activities. Some metabolic changes associated with adaption produce toxic metabolites (e.g. free fatty acids), which can be dealt with by incorporation into triacylglycerol. Collectively these changes to the cellular lipidome (the totality of lipids in cells) enable plants to adapt and survive in variable climates. Although all plants share the ability to remodel their cellular lipidome in response to abiotic stress, the capacity in different species and cultivars often varies. Currently, our understanding of lipid responses to abiotic stress largely comes from model species such as Arabidopsis, but there is now interest in using extremophile species, adapted to challenging climates, to dissect the mechanisms of plant lipid signalling and remodelling. Eutrema salsugineum ('salt cress') is highly resilient to abiotic stress (temperature and salinity). Moreover, as a member of the Brassica family and closely related to Arabidopsis it is a platform for understanding stress tolerance. The genome of Eutrema is fully sequenced and transformation methods have been established. The similarity between genomes of Eutrema and Arabidopsis allows a direct comparison between genes and their function, rendering most of the experimental procedures developed for Arabidopsis highly adaptable. The central aim of the proposed project is to clarify the biochemical processes and functional significance of stress induced lipid metabolism. Using both Arabidopsis and Eutrema, we will focus on the mechanistic response to temperature stress. Current and predicated climate variability has critical effects on food production, therefore the fundamental understanding developed in the proposed work will establish knowledge-based strategies to address crop temperature resilience.