Molecular, Biochemical, and Structural Studies of the Mechanism of S-RNase-Based Self-Incompatibility in Petunia

矮牵牛基于 S-RNase 的自交不亲和机制的分子、生化和结构研究

• 批准号: 2138062
• 负责人: Teh-hui Kao
• 金额: $ 70万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138062&HistoricalAwards=false
• 关键词: Molecular; Biochemical; Structural; Studies; Mechanism

Most flowering plant species produce flowers with male and female reproductive organs (anther and pistil) located in close proximity in the same flowers. This arrangement is conducive to self-fertilization, where pollen from the anther lands on the pistil and germinates, leading to fertilization of the ovule, followed by seed development. As plants cannot move freely to select mates, they have evolved a variety of strategies to prevent deleterious inbreeding. Self-incompatibility (SI) is one such strategy, by which the pistil rejects genetically identical self-pollen and only accepts non-self pollen for fertilization. SI is thought to be a major factor for the explosive success of flowering plants. Two fundamental questions are: how does a pistil distinguish self- and non-self pollen, and how does this self/non-self recognition result in specific rejection of self-pollen? Multiple mechanisms have been adopted by flowering plants to achieve this goal. The PI has been using Petunia inflata as a model to study a SI mechanism found in Solanaceae and two other families. In this project, the PI and his collaborator will use molecular, biochemical, genetic, genomic, and structural approaches to study this mechanism, employed by pollen, to mediate degradation of variants of a toxic protein produced by non-self pistils to allow outcrossing and to leave untouched the variant produced by self-pistils, allowing these pistils to destroy self-pollen tubes. The results have wider implications for the study of other biological systems employing self/non-self recognition. If the SI machinery could be reconstituted in crop plants to facilitate hybrid seed production, this would have tremendous agronomic benefits. The PI will engage a postdoc, and graduate and undergraduate students to prepare them for future professional careers and will host summer research of high school students. The outcome of pollination in Petunia inflata is determined by the polymorphic S-locus; matching of the pollen S-haplotype with either S-haplotype of the pistil results in growth inhibition of pollen tubes. S-RNase encodes the pistil determinant; multiple S-locus F-box (SLF) genes encode the pollen determinant. Based on the collaborative non-self recognition model, each SLF interacts with some of its non-self S-RNases to mediate their ubiquitination and degradation inside pollen tubes, thereby opening the door to non-self fertilization. None of the SLFs interact with their self S-RNase, allowing the S-RNAse to inhibit growth of self-pollen tubes. All SLFs are assembled into SCF (Skp1-Cullin1-F-Box protein) complexes, each containing self-incompatibility (SI)-specific Cullin1 (PiCUL1-P or PiCUL1-B) and Skp1 (PiSSK1) subunits, and a canonical Rbx1. This project will study three themes: SCFSLF-S-RNase interactions, nature of SCFSLF, and regulatory proteins of SCFSLF, SLF and S-RNase. Obj. I examines the role of two amino acids of S2-SLF1 in its specific interaction with S3-RNase; identifies protein(s) that is(are) required to stabilize the interaction between SCFS2-SLF1 and S3-RNase; determines the structure of SCFS2-SLF1:S3-RNase:X by Cryo-EM. Obj. II uses organelle and cytosol markers to determine whether SLFs are localized to the pollen tube cytosol. Obj. III examines the roles of the amino acids unique to PiSSK1, PiCUL1-P, and PiCUL1-B in their function in SI; and models the structure of SCFS2-SLF1. Obj. IV studies the proteins that may be involved in regulating the dynamics of SCFSLF (activation of the complex and degradation of SLFs). Obj. V examines the role of S-locus-localized PDIL (Protein Disulfide Isomerase-Like) in SI.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.

大多数开花的植物物种与雄性和女性生殖器官（花药和雌蕊）产生花朵，位于同一朵花中。这种布置有利于自施用，在雌蕊上，花药从雌蕊上降落在雌蕊上，导致胚珠的受精，然后进行种子发育。由于植物无法自由地选择伴侣，因此它们已经发展了多种策略，以防止有害近亲繁殖。自我兼容（SI）就是一种这样的策略，通过该策略拒绝遗传上相同的自主，并且仅接受非自身的花粉进行施肥。 SI被认为是开花植物爆炸性成功的主要因素。两个基本问题是：雌蕊如何区分自我和非自身的花粉，这种自我/非自我识别如何导致特定拒绝自主？开花植物已经采用了多种机制来实现这一目标。 PI一直在使用矮牵牛足体作为模型来研究甲酸和另外两个家庭中发现的SI机制。在该项目中，PI和他的合作者将使用分子，生化，遗传，基因组和结构方法研究这种机制，用于介导非素质的毒性蛋白质的变异降解，从而允许自我生产的自我生产，从而允许这些自我生产的自我生产，从而允许这些自我生产。结果对采用自我/非自我识别的其他生物系统的研究具有更大的影响。如果可以在作物植物中重组SI机械以促进杂交种子的生产，那么这将带来巨大的农艺益处。 PI将聘请博士后，毕业和本科生为未来的职业生涯做准备，并将主持高中生的夏季研究。矮牵牛的授粉结果取决于多态S-cocus。花粉s-光型与雌蕊的任何S-型型的匹配会导致花粉管的生长抑制。 S-RNase编码雌蕊决定因素；多个S-cocus F-box（SLF）基因编码花粉决定因素。基于协作非自我识别模型，每个SLF都与其一些非自身的S-RNass相互作用，以介导花粉管内的泛素化和降解，从而为非自身施肥打开了大门。 SLF都没有与他们的自s-RNase相互作用，从而使S-RNase抑制了自pollen管的生长。所有SLF均组装成SCF（SKP1-Cullin1-F-box蛋白）配合物，每个SLF都包含自我兼容性（SI） - 特异性Cullin1（PICUL1-P或PICUL1-B）和SKP1（PISSK1）亚基，以及一个规范的RBX1。该项目将研究三个主题：SCFSLF-S-RNase相互作用，SCFSLF的性质以及SCFSLF，SLF和S-RNase的调节蛋白。 OBJ。我研究了S2-SLF1的两个氨基酸在其与S3-RNASE的特定相互作用中的作用。识别稳定SCFS2-SLF1和S3-RNase之间相互作用所需的蛋白质；确定Cryo-Em的SCFS2-SLF1：S3-RNase：X的结构。 OBJ。 II使用细胞器和细胞质标记来确定SLF是否位于花粉管细胞质。 OBJ。 III研究了PISSK1，PICUL1-P和PICUL1-B在SI中的功能中所独有的氨基酸的作用；并建模SCFS2-SLF1的结构。 OBJ。 IV研究可能参与调节SCFSLF动力学的蛋白质（SLF的复合物和降解的激活）。 OBJ。 V研究了S-Ocus-localization PDIL（蛋白质二硫化物异构酶样）在SI中的作用。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。