Intramembrane Proteolysis in Regulation of the Rice Receptor Kinase XA21

植物防御细菌病害是一项耗资巨大的工作。免疫系统的过度扩增或失调通常会导致有害影响。因此，严格控制免疫传感器和限制对病原体感染组织的免疫反应被认为是宿主植物生存的关键。水稻细胞表面免疫传感器XA 21具有抗水分胁迫和抗白叶枯病的特性。（Xoo）.该项目将研究能够在细胞膜中切割XA21的蛋白质对XA21的调节。所获得的知识不仅将有助于农业应用，而且还将为博士后学者，研究生和本科生，预科生和来自标题I高中（包含40%或更高的少数民族和社会经济挑战学生群体）的24名教育工作者创造培训机会。通过参与该项目，参与者将学习尖端的科学思想和方法，并有助于发现可能具有广泛影响的知识。参与的教师将对一般和先进的分子技术产生兴趣和理解。因此，这些知识和兴趣最终将在本项目期间与高中学生在课堂上分享。年轻的研究人员和学生接触水稻及其疾病将有助于公民更好地了解农业和粮食安全。 膜内蛋白水解是一种进化上保守的细胞机制，介导脂质双层内跨膜蛋白的切割。然而，很少有人知道这个重要的调节过程中的植物，主要是由于缺乏已知的生物底物的广泛的膜内蛋白酶。限制XA21到叶1（LXL1）的膜内蛋白酶能够在植物中切割XA21。本项目旨在验证XA21作为LXL1在水稻中的生物底物，使用液相色谱质谱法确定XA21中的LXL1切割位点，并使用染料示踪和解剖分析来阐明在含有XA21的lxl1突变体中观察到的发育缺陷的潜在机制。同样使用这些Ixl1系，研究将确定LXL1介导的XA 21切割在脱水反应中的作用和早期分子事件。最后，该项目将表征对LXL1切割不敏感的XA 21水稻突变体。该项目将大大推进我们对高等植物膜内蛋白水解生物学的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Defense against bacterial disease is a costly undertaking by plants. Overamplification or dysregulation of the immune system often causes deleterious effects. Therefore, tight control of immune sensors and restriction of the immune response to pathogen-infected tissues are thought to be crucial for survival of the host plant. The rice cell-surface immune sensor XA21confers resistance to water-deficit stress and immunity against bacterial leaf blight disease caused by Xanthomonas oryzae pv. oryzae (Xoo). This project will study the regulation of XA21 by a protein capable of cleaving XA21 in the cell membrane. The knowledge gained will not only contribute to agricultural applications but will also create training opportunities for a postdoctoral scholar, graduate and undergraduate students, precollege students and a total of 24 educators from Title I high schools (containing minority and socioeconomically challenged student populations of 40% or greater). By engaging in this project, the participants will learn cutting-edge scientific ideas and methods and contribute to the discovery of knowledge that may have broad implications. The participating teachers will gain interest in and understanding of general and advanced molecular techniques. As a result, this knowledge and interest will ultimately be shared with high school students in their classrooms during the span of this project. The exposure of younger researchers and students to the crop rice and its diseases will help citizens better understand agriculture and food security. Intramembrane proteolysis is an evolutionarily conserved cellular mechanism that mediates cleavage of transmembrane proteins within the lipid bilayers. However, very little is known about this important regulatory process in plants, largely due to lack of known biological substrates of the widespread intramembrane proteases. The intramembrane protease Limiting XA21 to Leaf 1 (LXL1) is capable of cleaving XA21 in planta. This project aims to verify XA21 as a biological substrate of LXL1 in rice, to pinpoint the LXL1 cleavage site in XA21 using liquid chromatography mass spectrometry and to elucidate the mechanisms underlying the developmental defects observed in lxl1 mutants containing XA21 using dye tracer and anatomical assays. Also using these lxl1 lines, the studies will determine the roles and early molecular events of LXL1-mediated cleavage of XA21 in dehydration responses. Finally, the project will characterize XA21 rice mutants that are insensitive to LXL1 cleavage. This project will significantly advance our understanding of the biology of intramembrane proteolysis in higher plants.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.