Signaling function of phloem lipids and lipid-binding proteins in development and response to stress

全球气候变化造成重大的非生物压力（盐碱化、干旱），对作物生产构成重大挑战。与动物不同，植物不能移动以逃避不利条件。因此，它们进化出了检测环境变化的机制，将这些变化传达给不同的器官，并相应地调整发育。这些适应之一是韧皮部，这是一个长距离运输途径，对于环境线索的交流至关重要。确定信号的性质和它们通过韧皮部进行通信的机制将导致更全面地了解植物如何调整发育以应对压力。已知脂质在细胞水平上充当信号。然而，它们在长距离信令中的作用很少受到关注。这是一个新的研究领域，有望为植物发展提供新的概念。 为了作为长距离信号，脂质必须释放到韧皮部，与蛋白质“伴侣”结合，并被受体检测到。一项对拟南芥韧皮部分泌物的早期研究揭示了在执行这些功能中具有潜在作用的脂质结合蛋白。脂肪酶可以在脂质释放中发挥作用;韧皮部脂质相关家族蛋白（PLAFP）是一种预测的应激诱导的脂质结合蛋白，可以促进整个韧皮部的脂质运输; PIG-P蛋白（磷脂酰肌醇N-乙酰葡糖胺转移酶的P亚基）可以作为脂质受体的一部分发挥作用。该项目旨在利用生物化学，分子生物学，显微镜和质谱来表征这些蛋白质在响应非生物胁迫（干旱，盐，渗透）时的表达，研究脂质结合特性，并研究脂质结合和蛋白质表达的变化对这种胁迫反应和磷脂谱的影响。这些实验将与一名研究生、一名本科生和一名高中生一起进行，将深入了解压力诱导的脂质信号传导机制及其对植物对不断变化的环境的反应的影响。

Changes in the global climate exert significant abiotic stresses (salinity, drought) and constitute major challenges for crop production. Unlike animals, plants cannot move to escape adverse conditions. Hence, they evolved mechanisms to detect changes in their environment, communicate these to different organs, and adjust development accordingly. One of these adaptations is the phloem, a long-distance trafficking pathway, which is essential for the communication of environmental cues. Determining the nature of signals and the mechanisms by which they are communicated through the phloem will lead to a more complete understanding of how the plant adjusts development in response to stress. Lipids are known to act as signals at the cellular level. However, their role in long distance signaling has received little attention. It is a new area of research which is expected to contribute new concepts to plant development. To act as long-distance signals, lipids have to be released into the phloem, moved bound to a protein "chaperone", and be detected by a receptor. An earlier study of Arabidopsis phloem exudates revealed lipid-binding proteins with potential roles in performing those functions. Lipases could function in the release of lipids; phloem lipid-associated family protein (PLAFP), a predicted stress-induced lipid-binding protein, could facilitate lipid transport throughout the phloem; PIG-P proteins (subunit P of a phosphatidylinositol N-acetylglucosaminyltransferase) could function as part of a lipid receptor. This project aims to use biochemistry, molecular biology, microscopy, and mass spectrometry to characterize the expression of these proteins in response to abiotic stresses (drought, salt, osmotic), investigate the lipid-binding characteristics, and study the impact changes in lipid-binding and protein expression have on this stress response and the phospholipid profile. The experiments, which will be conducted with a graduate student, undergraduate student, and a high school student, will provide an insight into the mechanism of stress-induced lipid signaling and its effect on the plant's response to our changing environment.