Microbial Genome Sequencing: Genomic Biodiversity in Hypersaline Environments

极端嗜盐古菌生活在含3-5 M NaCl的盐池中，这些盐池在盐度、pH、温度、压力、营养物等方面具有异常多样性和动态性。除了它们的专性嗜盐特征外，有些古菌还嗜酸、嗜碱、嗜冷、嗜压或轻度嗜热。极端嗜盐菌易于在实验室中培养，是具有发达遗传工具的优良实验系统。然而，到目前为止，只有一个单一的基因组从极端嗜盐古菌，Halobacterium speciesNRC-1，已被测序。为了研究极端嗜盐菌的基因组多样性，我们计划对海洋嗜盐菌（Haloarcula marismortui）的基因组进行测序，海洋嗜盐菌是一种具有高分辨率核糖体结构的代谢多功能嗜盐菌。如果时间和资源允许，将对不同的菌株进行更多的基因组分析，包括亚洲钠藻，一种无色素的嗜碱菌; Halorubrum lacusprofundi，一种能够在4 ℃以下生长的嗜冷菌; Halosimplex carlsbadense，一种最近从二叠纪盐水包裹体中分离出来的可能的古老嗜盐菌，这似乎是一种遗传嵌合体;以及Halobacterium species GRB，一种与NRC-1密切相关的菌株。 测序将在系统生物学研究所进行，注释将在马里兰州大学生物技术研究所海洋生物技术中心进行。该项目将使人们更好地了解极端嗜盐生物的生物多样性，包括基因组结构和进化、对极端环境的适应和横向基因转移。从长远来看，拟议的工作将提供新的应用在生物技术，如工程作物耐盐性和开发新的抗生素。这是一个微生物基因组测序奖，由美国国家科学基金会和农业部未来农业和食品系统倡议之间的合作计划资助。

Extremely halophilic archaea inhabit brine pools containing 3-5 M NaCl, which areextraordinarily diverse and dynamic with respect to salinity, pH, temperature, pressure, nutrients,etc. In addition to their obligately halophilic character,some are also acidophilic, alkaliphilic,psychrophilic, barophilic, or slightly thermophilic. Extreme halophiles are easily cultured in thelaboratory and are excellent experimental systems with well-developed genetic tools. However,thus far, only a single genome from an extremely halophilic archaeon, Halobacterium speciesNRC-1, has been sequenced. In order to study the genomic diversity of extreme halophiles, weplan to sequence the genome of Haloarcula marismortui, a metabolically versatile halophile witha high-resolution ribosome structure. If time and resources permit, additional genomic analysiswill be conducted on diverse strains, including Natrialba asiatica, a non-pigmented alkaliphile.Halorubrum lacusprofundi, a psychrophile capable of growing at temperatures down to 4oC,Halosimplex carlsbadense, a likely ancient halophile recently isolated from a Permian brineinclusion, which appears to be a genetic chimera, and Halobacterium species GRB, a closelyrelated strain to NRC-1. Sequencing will be conducted at the Institute for Systems Biology andannotation will be done at the University of Maryland Biotechnology Institute, Center of MarineBiotechnology. This project will provide better understanding of biodiversity among extremehalophiles, including genome structure and evolution, adaptation to extreme environments, andlateral gene transfer. In the long term, the proposed work should provide novel applications inbiotechnology, e.g. engineering salt tolerance in crop plants and development of new antibiotics. This is a Microbial Genome Sequencing Award funded through a collaborative program between the National Science Foundation and the Department of Agriculture Initiative for Future Agriculture and Food Systems.