EAGER: Elucidation of the Potential for CAM Photosynthesis in the C4 Halophyte Spinifex littoreus, a Succulent Asian Grass with Enormous Agricultural Potential

EAGER：阐明 C4 盐生植物 Spinifex littoreus（一种具有巨大农业潜力的多汁亚洲草）的 CAM 光合作用潜力

• 批准号: 1411897
• 负责人: Craig Martin
• 金额: $ 27.99万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1411897&HistoricalAwards=false
• 关键词: EAGER; Elucidation; Potential; CAM; Photosynthesis

Recently, the PI and international collaborators discovered that a coastal grass in Taiwan has a very unusual type of photosynthesis, the mechanism that plants use to make food (theirs and ours). This type of photosynthesis has only been found in one other small group of plants, and scientists are still puzzled by its significance. This discovery is particularly interesting because the plant is a grass, and one consequence of its unusual type of photosynthesis is a considerable savings of water. These two observations become even more interesting from an agricultural perspective because most of the world?s grain crops derive from grasses, and irrigation of such grasses is depleting world reservoirs/aquifers and creating difficulties wherever such water demands exceed supply. The grass that is the focus of the proposed research may well provide a source of the genetic underpinnings for conserving water and reducing irrigation demands worldwide. The immediate work proposed by the PI comprises field and laboratory investigations of the unusual photosynthesis in this grass with the goal of determining under what conditions it most expresses its water-conservative physiology. This research lays the groundwork for further genetic and agricultural work.Although species with CAM photosynthesis are now known from over 30 different plant families, no species in one of the largest extant families, the Poaceae (grasses), has been reported as having CAM. Preliminary research by the PI and his colleagues, however, has discovered variable levels of Crassulacean Acid Metabolism (CAM) in the succulent halophytic grass, Spinifex littoralis, a C4 species that grows in coastal areas throughout Southeast Asia. This is the first known report of succulence and of CAM in a species of Poaceae. The goals of the proposed research are to determine why CAM is variable and which environmental factors are most important in promoting the greatest degree of CAM in this succulent C4 grass. Diurnal patterns of leaf gas exchange, titratable acidity, and PEP carboxylase activity will be monitored in the field and in the lab under varying conditions of irradiance, water status, and soil salinity. Plants for these investigations will be sampled from different populations in different habitats in Taiwan, including those with and without competitors. Other measurements to be made include light-use efficiency using PAM fluorometry, leaf tissue anatomy (especially degree of succulence), and leaf water potential. In addition, the proposed research, in collaboration with molecular plant physiologists, includes preliminary work designed to determine how best to prepare use of this plant for genetic purposes with the goal of transferring CAM genes to agricultural grain species.

最近，PI和国际合作者发现，台湾的沿海草有非常不寻常的光合作用类型，即植物用来制造食物的机制。 这种类型的光合作用仅在其他一小群植物中发现，科学家仍然对其意义感到困惑。 这一发现特别有趣，因为该植物是草，其不寻常的光合作用的结果是大量的水。 从农业角度来看，这两种观察结果变得更加有趣，因为世界上大多数谷物作物都来自草，而这种草的灌溉正在耗尽世界储层/含水层，并在此类水需求超过供应的任何地方都会造成困难。 拟议研究的重点的草很可能为节省水和减少全球灌溉需求的遗传基础提供了根源。 PI提出的直接工作包括对这草中异常光合作用的现场和实验室调查，目的是在哪种条件下确定其表达其水分保守的生理学。 这项研究为进一步的遗传和农业工作奠定了基础。尽管现在有30多个不同的植物科中知道具有CAM光合作用的物种，但在现存最大的家族之一中没有物种，但据报道，Poaceae（Grasse）已被报道为CAM。 然而，PI及其同事的初步研究发现了在多肉肉质盐生含量的草，pinifex littoralis的碎屑酸代谢（CAM），这是一种在整个东南亚沿海地区生长的C4物种。这是肉豆谷物种中的多肉和凸轮的第一个已知报告。拟议的研究的目标是确定CAM为什么可变，哪些环境因素对于促进这种多汁的C4草的最大凸轮最重要。 叶子气体交换，可滴定酸度和PEP羧化酶活性的昼夜模式将在现场和实验室中监测在不同的辐照度，水状态和土壤盐度的不同条件下。 这些研究的植物将从台湾不同栖息地的不同人群中进行采样，包括有和没有竞争者的植物。要进行的其他测量包括使用PAM荧光测定法，叶组织解剖结构（尤其是多肉液）和叶水潜力的轻型效率。此外，拟议的研究与分子植物生理学家合作，包括初步工作，旨在确定如何最好地准备该植物作为遗传目的，目的是将CAM基因转移到农业谷物物种。