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

全球气候的变化造成了重大的非生物胁迫（盐度、干旱），对作物生产构成了重大挑战。与动物不同，植物不能通过移动来逃避恶劣的环境。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。其中一种适应是韧皮部，这是一种长途运输途径，对环境信号的交流至关重要。确定信号的性质和它们通过韧皮部传递的机制将使我们更全面地了解植物如何调节发育以应对压力。众所周知，脂质在细胞水平上起到信号的作用。然而，它们在远距离信号中的作用却很少受到关注。这是一个新的研究领域，有望为植物的发展提供新的理念。为了充当远距离信号，脂质必须被释放到韧皮部，与蛋白质“伴侣”结合，并被受体检测到。早期对拟南芥韧皮部分泌物的研究揭示了脂质结合蛋白在执行这些功能方面的潜在作用。脂肪酶在脂质的释放中起作用；韧皮部脂质相关家族蛋白（PLAFP）是一种预测的应激诱导脂质结合蛋白，可促进韧皮部脂质转运；猪-P蛋白（磷脂酰肌醇n -乙酰氨基葡萄糖转移酶的P亚基）可以作为脂质受体的一部分发挥作用。本项目旨在利用生物化学、分子生物学、显微镜和质谱等手段，对这些蛋白在非生物胁迫（干旱、盐、渗透）下的表达进行表征，探讨脂质结合特性，研究脂质结合和蛋白表达的变化对这种胁迫反应和磷脂谱的影响。该实验将由一名研究生、一名本科生和一名高中生共同进行，将深入了解应激诱导的脂质信号传导机制及其对植物对环境变化的反应的影响。

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.