Genetic Analysis of Crassulacean Acid Metabolism in Mesembryanthemum crystallinum

大多数高等植物利用核酮糖二磷酸羧化酶/加氧酶（RUBISCO）通过光合作用的C3途径同化大气CO2。 然而，当环境压力条件下减少CO2的可用性，增加光呼吸降低C3光合作用的效率。 为了克服光呼吸的浪费过程，大约10%的高等植物物种已经进化出两种可供选择的光合CO2同化策略。 这些替代的碳固定途径，C4光合作用和景天科酸代谢（CAM），采用CO2泵将CO2集中在RUBISCO附近的植物组织内。 这一过程提高了C4和CAM植物在环境胁迫条件下的竞争力，如高光强度、高温或低水可用性。 然而，与C4植物不同，CAM植物主要在夜间吸收CO2，限制了白天通过蒸腾作用损失的水分，大大提高了水分利用效率。 本研究的目的是确定和表征CAM途径的关键结构和调控成分，通过分离突变体CAM缺陷使用常见的冰植物（Mesembryocarcinum stac um）作为模型系统。 为了补充这种方法，将通过对表达基因的随机选择的互补DNA（cDNA）拷贝进行测序来建立表达序列标签（EST）的非冗余数据库。 该EST集合将为鉴定CAM植物特有的新基因或基因家族成员和表达模式提供丰富的序列信息来源。 本研究所获得的突变体和EST库将为全世界研究CAM植物的研究人员提供不可或缺的资源。 大量的核苷酸序列信息的EST和基因组测序项目在各种模式生物的可用性正在迅速改变生物学研究的方式进行，并产生了迫切需要教育科学家在生物信息的分析和研究（生物信息学）。 为了有效地利用生物信息资源，一个综合的教育和研究计划将集中在生物信息学的教学和培训机会。 一个学期的生物信息学课程，一个简短的“动手”生物信息学研讨会，和一系列的教学模块（与计算机实验室）将开发研究生，本科生和高中学生将学习如何使用信息工具和资源，通过积极参与M。堆积了EST测序工作。 通过这种方式，对CAM遗传基础的研究将与一系列独特的教学机会相结合，这些机会将联合收割机基于研究的经验与生物信息学的前沿培训相结合。

9722285 Cushman Most higher plants assimilate atmospheric CO2 through the C3 pathway of photosynthesis using ribulose bis-phosphate carboxylase/oxygenase (RUBISCO). However, when environmental-stress conditions reduce the availability of CO2, increased photorespiration reduces the efficiency of C3 photosynthesis. To overcome the wasteful process of photorespiration, about 10% of higher-plant species have evolved two alternative strategies for photosynthetic CO2 assimilation. These alternative carbon-fixation pathways, C4 photosynthesis and Crassulacean acid metabolism (CAM), employ a CO2 pump to concentrate CO2 within plant tissues near RUBISCO. This process improves the competitiveness of C4 and CAM plants under environmental-stress conditions such as high light intensity, high temperatures, or low water availability. Unlike C4 plants, however, CAM plants assimilate CO2 mostly at night, limiting daytime water loss through transpiration and greatly improving water-use efficiency. The goal of this research is to identify and characterize key structural and regulatory components of the CAM pathway by isolating mutants defective in CAM using the common ice plant (Mesembryanthemum crystallinum) as a model system. To complement this approach, a non-redundant database of expressed-sequence tags (ESTs) will be established by sequencing randomly selected complementary DNA (cDNA) copies of expressed genes. This EST collection will provide a rich source of sequence information for identifying novel genes or gene-family members and expression patterns peculiar to CAM plants. The mutant and EST collections generated by this research will provide an indispensable resource for researchers worldwide investigating CAM plants. The availability of large amounts of nucleotide-sequence information from EST and genome-sequencing projects in a variety of model organisms is rapidly changing the way in which biological research is conducted and has generated a pressing need to educate scientists in the analysis and study of biological information (Bioinformatics). To exploit biological-information resources effectively, an integrated educational and research program will focus on instructional and training opportunities in Bioinformatics. A semester-long Bioinformatics course, an abbreviated "hands-on" Bioinformatics workshop, and a series of instructional modules (with computer lab) will be developed where graduate, undergraduate, and high-school students will learn how to use informatic tools and resources through active participation in the M. crystallinum EST-sequencing effort. In this way, the research on the genetic basis of CAM will be integrated with a series of unique instructional opportunities that combine research-based experiences with cutting-edge training in Bioinformatics.