Evolutionary Diversification of Photosynthesis and the Anoxygenic to Oxygenic Transition

J. Touchman博士（亚利桑那州立大学），R. Blankenship（华盛顿州立大学）和M. Madigan（Southern Illinois University）正在进行五种光合原核生物的基因组测序和代谢分析。选择该项目的生物体，以提供比现在更广泛的光养类群基因组的覆盖范围。该项目的主要目标是利用基因组数据来了解光合作用的起源和进化，并探索缺氧到有氧转变的机制。正在测序的生物包括生活在低温（嗜冷）、高温（嗜热）、高pH（嗜碱）、周期性干燥环境和高硫化物环境中的物种。所选的生物体包括两种日光菌，旋绕日光菌和带状日光菌;四种变形菌，Rhodoferax anarcticus，Rhodopila globiformis，Blastochloris viridis和Thermochromatium tepidum;以及一种蓝细菌，Leptolyngbya（a.k.a.双粒颤藻）变形菌包括来自β和γ分裂的成员以及含有细菌叶绿素B作为其主要色素的细菌。已完成的注释基因组序列正被用于填补光合原核生物可用基因组数据中的巨大空白。这些生物体的代谢能力也正在使用途径分析软件工具进行分析。每种生物都有其独特的特征，这些特征证明了其在基因组测序项目中的合理性，包括进化关系，农业应用和环境方面。Touchman博士参与了ASU的生物学家计划。所有的研究人员都让本科生和高中生在他们的实验室里参与序列分析和注释活动。

Drs. J. Touchman (Arizona State Univ), R. Blankenship (Washinton State Univ) and M. Madigan (Southern Illinois Univ.) are carrying out the genome sequencing and metabolic analysis of five photosynthetic prokaryotes. Organisms for this project were chosen to provide significantly wider coverage of genomes of phototrophic taxa than is now available. The broad goals of the project are to use the genomic data to understand the origin and evolution of photosynthesis and to explore mechanisms of the anoxygenic to oxygenic transition. The organisms being sequenced include species that live at low temperature (psychrophilic), high temperature (thermophilic), high pH (alkaliphilic), in environments subject to periodic drying, and environments high in sulfide. The organisms chosen include two heliobacteria, Heliorestis convoluta and Heliophilum fasciatum; four proteobacteria, Rhodoferax antarcticus, Rhodopila globiformis, Blastochloris viridis, and Thermochromatium tepidum; and one cyanobacterium, Leptolyngbya (a.k.a. Oscillatoria) amphigranulata. The proteobacteria include members from the beta and gamma divisions and one that contains bacteriochlorophyll b as its principal photopigment. The finished, annotated genome sequences are being used to fill large gaps in the available genomic data for photosynthetic prokaryotes. The metabolic capabilities of these organisms are also being analyzed using pathway analysis software tools. Each organism has individual characteristics that justify its inclusion in a genome-sequencing project, including evolutionary relationships, agricultural applications and environmental aspects.Dr. Touchman is involved in the Be a Biologist program at ASU. All of the investigators are involving undergraduate and high school students in sequence analysis and annotation activities in their labs.