CLE effector peptide signaling in plant-nematode interactions

植物-线虫相互作用中的 CLE 效应肽信号传导

• 批准号: 1456047
• 负责人: Melissa Mitchum
• 金额: $ 67.14万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1456047&HistoricalAwards=false
• 关键词: CLE; effector; peptide; signaling; plant

Plant-parasitic nematodes are a major impediment to meeting the challenge of feeding a population projected to reach 9 billion by 2050. These nematodes cause billions of dollars in yield losses annually worldwide. The unavailability or limited genetic base of commercially acceptable resistant cultivars, genotypic variability in nematode field populations, as well as the emergence of new species, pose a continued threat to crop production by this group of agriculturally important pests. The most economically important plant-parasitic nematodes include the cyst forming nematodes. Cyst nematodes form parasitic relationships with their plant hosts by establishing a permanent feeding site within the root, which serves as a nutrient sink to support growth and development of the nematode. This project will provide new insights into how plants recognize and respond to nematode-secreted molecules to form unique and essential feeding cells within host roots, which may, in turn, translate into novel strategies to bioengineer crops with robust resistance to pathogenic cyst nematodes. The investigators seek to understand the detailed molecular mechanisms and pathways by which plant-parasitic cyst nematodes co-opt host developmental programs for feeding cell formation. Feeding cell development and maintenance is dependent on stylet-secreted effector proteins produced in the esophageal gland cells of cyst nematodes. However, our understanding of signaling processes directing the process of host cell transformation by nematode-secreted effectors is largely lacking. Among the stylet-secreted effectors are small signaling peptides sharing similarity with plant CLAVATA3/ENDOSPERM SURROUNDING REGION-related (CLE) peptides. The investigators have demonstrated that these nematode-secreted peptide signals are required for successful infection, but their exact role in developmental reprogramming of root cells for feeding cell formation remains unclear. The project focuses on elucidating the function of nematode-secreted CLE peptides in modulating the plant cellular program for feeding cell formation. Molecular, genetic, genomic, and biochemical analyses will be used to characterize the role of nematode CLE peptides in feeding cell formation. Once delivered into host cells, CLE proteins are retargeted to the apoplast via a novel post-translational trafficking mechanism. The trafficking pathway will be investigated through subcellular localization and analyses of host-interacting proteins. In the apoplast, CLE peptides are perceived by plant receptors. Receptor localization will be characterized and deletion and mutagenesis studies will be used to evaluate receptor binding specificity to nematode CLE peptides. The hypothesis that CLE peptides act to modulate phytohormone and defense signaling pathways will be tested through cell-specific studies of mutants, reporter lines, and other related assays including nematode infection assays and in vitro peptide application assays. The data generated will provide information about a class of pathogen effectors unique to plant-parasitic cyst nematodes and the first example of a pathogen secreting a protein mimic of a plant peptide hormone. Beyond the cyst nematode-plant interaction, the data generated will contribute to an understanding of CLE signaling and potentially novel protein trafficking pathways in plants. The project will integrate research activities with education and training of female and underrepresented minority undergraduate students in plant molecular genetics and cell biology through outreach programs targeting K-5 focused on applications of plant science and technology for society.

植物寄生线虫是应对到2050年预计将达到90亿人口的挑战的主要障碍。 这些线虫每年在全世界造成数十亿美元的产量损失。商业上可接受的抗性栽培品种的不可用性或有限的遗传基础、线虫田间种群的基因型变异性以及新物种的出现，这组农业上重要的害虫对作物生产构成持续的威胁。经济上最重要的植物寄生线虫包括包囊形成线虫。孢囊线虫通过在根内建立永久的取食场所与其植物宿主形成寄生关系，根作为营养库以支持线虫的生长和发育。该项目将为植物如何识别和响应线虫分泌的分子提供新的见解，以在宿主根内形成独特和必要的饲养细胞，这反过来可能转化为生物工程作物对致病性胞囊线虫具有强大抗性的新策略。研究人员试图了解详细的分子机制和途径，植物寄生的孢囊线虫COOP宿主发育程序的喂养细胞的形成。囊线虫食道腺细胞中分泌的效应蛋白是其摄食细胞发育和维持的关键。然而，我们的理解，指导宿主细胞转化的过程中，线虫分泌的效应在很大程度上是缺乏的。在针分泌的效应物中，有与植物CLAVATA 3/胚乳周围区域相关（CLE）肽具有相似性的小信号肽。研究人员已经证明，这些线虫分泌的肽信号是成功感染所必需的，但它们在根细胞发育重编程以形成饲养细胞中的确切作用仍不清楚。该项目的重点是阐明线虫分泌的CLE肽在调节植物细胞饲养细胞形成程序中的功能。分子，遗传，基因组和生化分析将被用来表征线虫CLE肽在饲养细胞形成中的作用。一旦被递送到宿主细胞中，CLE蛋白通过一种新的翻译后运输机制被重定向到质外体。运输途径将通过亚细胞定位和分析主机相互作用的蛋白质。在质外体中，CLE肽被植物受体感知。将表征受体定位，并将使用缺失和诱变研究来评价对线虫CLE肽的受体结合特异性。CLE肽用于调节植物激素和防御信号传导途径的假设将通过突变体的细胞特异性研究、报告细胞系和其他相关测定（包括线虫感染测定和体外肽应用测定）来测试。所产生的数据将提供关于一类植物寄生孢囊线虫特有的病原体效应子的信息，以及病原体分泌植物肽激素的蛋白质模拟物的第一个例子。除了孢囊线虫与植物的相互作用，所产生的数据将有助于理解CLE信号传导和植物中潜在的新型蛋白质运输途径。该项目将通过针对K-5的外展计划，将研究活动与女性和代表性不足的少数族裔本科生在植物分子遗传学和细胞生物学方面的教育和培训结合起来，重点关注植物科学和技术在社会中的应用。