The regulation of meristem development in Ceratopteris gametophytes and sporophytes

角蕨配子体和孢子体分生组织发育的调控

• 批准号: 1931114
• 负责人: Yun Zhou
• 金额: $ 61.17万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1931114&HistoricalAwards=false
• 关键词: regulation; meristem; development; Ceratopteris; gametophytes

Plant shoot apical meristems, which contain stem cells and are found at the growing tips of plants, are essential for plants to grow tall and make leaves, flowers, fruits and seeds. Over three hundred million years, shoot meristems have evolved from a simple structure in non-seed plants, including ferns, to a complex structure in flowering plants. Using Ceratopteris (known as C-fern) as a model, the work interrogates the evolution of the meristem in land plants. In its life cycle, C-fern alternates between a haploid gametophyte and a diploid sporophyte stage, both having very distinct meristems. This research addresses how meristem development is regulated during these two generations. The research takes advantage of Ceratopteris as an effective and popular educational tool to engage K-12 science teachers, high school students, and undergraduates. Through summer workshops, high school science teachers from Indiana and Illinois, including those with limited resources for biology education, gain hands-on training to develop interactive lab exercises for their biology classes. High school students from underrepresented groups, recruited through established summer programs at Purdue, directly participate in the research. Aspects of the project also are integrated into undergraduate courses that the investigators teach, including plant anatomy, development and systematics. Lab exercises in plant anatomy, for example, include microscopic observations and quantification of fern gametophytes from wild type and transgenic plants, providing unique opportunities for undergraduates to get hands-on research experiences while benefiting the research project.Shoot apical meristems (SAMs) of seed plants are typically composed of multiple cell layers with distinct cell types, for example, the tunica-corpus organization in most angiosperms. In contrast, SAMs of non-seed vascular plants, including ferns, are simple, composed of a single large apical initial cell and its derivatives. Furthermore, non-seed vascular plants develop meristems in their independent, haploid and free-living gametophytes; whereas seed plant gametophytes do not have a meristem and are dependent on surrounding diploid sporophytic tissues. These differences raise two important but unresolved questions: are gametophyte and sporophyte meristems regulated by common pathways in ferns, and are the complex SAMs in seed plants and the simple SAMs in non-seed vascular plants controlled by similar mechanisms? Using the fern Ceratopteris richardii as a model system, the research tackles these questions employing multiple approaches, including transcriptome and phylogenetic analyses, gene-editing and gene silencing, time-lapse live imaging of fluorescence reporters for genes, proteins and distinct cell types, and computational image quantification. The research has great potential to reveal the ancestral function of meristem regulators in non-seed vascular plants, and uncover the molecular mechanisms underlying the initiation and maintenance of haploid gametophyte meristems and diploid sporophyte meristems of a model fern species. Given the importance of stem cells and the conserved function of the meristems in land plants, this work lays the groundwork for understanding how complex meristems observed in seed plants evolved from the simple meristems typical of ferns.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.

植物茎尖分生组织含有干细胞，存在于植物的生长顶端，是植物长高、形成叶、花、果实和种子所必需的。 经过3亿多年的发展，茎分生组织已经从非种子植物（包括蕨类植物）的简单结构演变为开花植物的复杂结构。 以水蕨属（C-fern）为模型，研究了陆生植物分生组织的演化。 在其生活史中，C-fern在单倍体配子体和二倍体孢子体阶段之间交替，两者都具有非常明显的分生组织。 这项研究解决了如何分生组织的发展是在这两个世代的调节。 这项研究利用水蕨作为一种有效和流行的教育工具，从事K-12科学教师，高中生和本科生。通过暑期讲习班，来自印第安纳州和伊利诺伊州的高中科学教师，包括那些生物教育资源有限的教师，获得了动手培训，为他们的生物课开发交互式实验室练习。 来自代表性不足群体的高中生，通过普渡大学的暑期项目招募，直接参与研究。 该项目的各个方面也被整合到研究人员教授的本科课程中，包括植物解剖学，发育和系统学。 例如，植物解剖学的实验练习包括野生型和转基因植物的蕨类配子体的显微观察和定量，为本科生提供了独特的机会，获得实践研究经验，同时有利于研究项目。种子植物的茎顶端分生组织（SAMs）通常由具有不同细胞类型的多个细胞层组成，例如，大多数被子植物中的套囊体组织。与此相反，非种子维管植物，包括蕨类植物，自组装体是简单的，由一个大的顶端原始细胞及其衍生物。此外，非种子维管植物在其独立、单倍体和自由生活的配子体中发育分生组织;而种子植物配子体不具有分生组织，并且依赖于周围的二倍体孢子体组织。这些差异提出了两个重要但尚未解决的问题：配子体和孢子体分生组织在蕨类植物中受共同途径的调节，种子植物中复杂的自组装膜和非种子维管植物中简单的自组装膜受相似机制的控制吗？使用蕨类Ceratopteris richardii作为模型系统，该研究采用多种方法解决这些问题，包括转录组和系统发育分析，基因编辑和基因沉默，基因，蛋白质和不同细胞类型的荧光报告分子的延时实时成像，以及计算图像定量。该研究对于揭示非种子维管植物分生组织调控因子的祖先功能，揭示模式蕨类植物单倍体配子体分生组织和二倍体孢子体分生组织发生和维持的分子机制具有重要意义。鉴于干细胞的重要性和陆地植物分生组织的保守功能，这项工作为理解种子植物中观察到的复杂分生组织是如何从蕨类植物典型的简单分生组织进化而来奠定了基础。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

项目成果

N-terminal region is required for functions of the HAM family member

• DOI: 10.1080/15592324.2021.1940001
• 发表时间: 2021-06-23
• 期刊: PLANT SIGNALING & BEHAVIOR
• 影响因子: 2.9
• 作者: Geng, Yuan;Zhou, Yun
• 通讯作者: Zhou, Yun

Conservation and diversification of HAIRY MERISTEM gene family in land plants

• DOI: 10.1111/tpj.15169
• 发表时间: 2021-03-27
• 期刊: PLANT JOURNAL
• 影响因子: 7.2
• 作者: Geng, Yuan;Guo, Lei;Zhou, Yun
• 通讯作者: Zhou, Yun

Timing of meristem initiation and maintenance determines the morphology of fern gametophytes

分生组织起始和维持的时间决定了蕨类配子体的形态

• DOI: 10.1093/jxb/erab307
• 发表时间: 2021
• 期刊: Journal of Experimental Botany
• 影响因子: 6.9
• 作者: Wu, Xiao;Yan, An;McAdam, Scott A;Banks, Jo Ann;Zhang, Shaoling;Zhou, Yun
• 通讯作者: Zhou, Yun