RESEARCH-PGR: Transdisciplinary Comparative Analyses of Halophytic and Glycophytic Grasses to Reveal Novel Mechanisms of Salt Tolerance

土壤盐碱化是一个日益严重的全球性问题，极大地限制了作物生产。 大多数作物是盐敏感的（糖植物），提高耐盐性的育种取得了有限的成功。 然而，一小部分开花植物可以在盐条件下完成其生命周期，并被认为是盐生植物。 一些盐生植物与盐敏感作物密切相关，研究盐生植物与盐生植物近缘种之间的遗传、形态、生理和生化差异，可能会发现可用于提高作物耐盐性的新机制。 此外，有人假设，与盐生植物相关的糖生植物物种可能已经具有耐盐性所需的大部分基本机制。 该项目将侧重于盐生草坪草海滨雀稗和结缕草，它们的叶子适应性使植物能够隔离和/或排泄盐，以及它们对盐敏感的亲戚高粱和小米，这两种谷类作物。 了解盐生植物盐适应背后的遗传学将最终在提高耐盐性的育种中找到应用。 此外，该项目将被用作培训研究生和本科生的工具，并向6-12年级学生介绍基于探究的学习，并向他们灌输对植物科学的热情。该项目建立在初步研究结果的基础上，初步研究确定了叶表面的结构适应以及新型硫酸化聚糖的存在，作为盐生草海滨雀稗（Paspalum vaginatum）的标志。 该项目结合元素图谱、MALDI-mass spectrometry imaging以及生化、生理和遗传分析，对属于两个分类群Panicoideae和Chloridoidea的盐生草和糖生草进行研究，旨在研究（1）硫酸盐是否是高盐下盐生草生长所必需的;（2）离子是否是盐生草生长所必需的;（3）硫酸盐是否是盐生草生长所必需的。（3）硫酸化多糖的组成和生物合成途径;（4）叶片适应在盐生植物耐盐性中的作用，（5）参与这些结构和生化适应的基因。在分类组内的盐生植物和糖生植物亲缘植物之间的比较分析代表了一种新的方法，以确定有助于耐盐性的性状。该奖项反映了NSF的法定使命，并已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的支持。

Soil salinity is an increasing problem worldwide, and greatly limits crop production. Most crop plants are salt sensitive (glycophytes), and breeding for improved salt tolerance has met with limited success. A small percentage of flowering plants, however, can complete their life cycle under saline conditions, and are considered halophytes. Some halophytes are closely related to salt-sensitive crop plants and an investigation of the genetic, morphological, physiological and biochemical differences between glycophytic crops and their halophytic relatives may identify novel mechanisms that can be used to increase the salt tolerance of crops. Furthermore, it has been hypothesized that glycophytic species related to halophytes may already have most of the basic machinery needed for salt tolerance. This project will focus on the halophytic turfgrasses seashore paspalum and zoysiagrass, which have leaf adaptations that allow plants to sequester and/or excrete salt, and their salt-sensitive relatives sorghum and finger millet, two cereal crops. Understanding the genetics behind salt-adaptations in halophytes will ultimately find applications in breeding for enhanced salt tolerance. Furthermore, the project will be used as a vehicle to train graduate and undergraduate students, and to introduce 6-12 graders to inquiry-based learning and instill in them a passion for plant science. The project builds on the results of preliminary studies that identified structural adaptations on the leaf surface as well as the presence of novel sulfated glycans as hallmarks of the halophytic grass seashore paspalum (Paspalum vaginatum). Combining element mapping, MALDI-mass spectrometry imaging, and biochemical, physiological and genetic analyses in halophytic and glycophytic grasses belonging to two taxonomic groups, the Panicoideae and Chloridoidea, the project aims to investigate (1) whether sulfate is essential to halophytic growth under high salt; (2) whether ions (e.g. Na+, K+) and sulfur-containing compounds accumulate differentially in halophytes and glycophytes; (3) the composition and biosynthetic route of sulfated glycan; (4) the role of leaf adaptations in salt tolerance of halophytes; and (5) the genes involved in these structural and biochemical adaptations. The comparative analyses between halophytes and glycophytic relatives within taxonomic groups represent a novel approach to identify traits that contribute to salt tolerance.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.