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Selection of host specific genes in environmentally transmitted mutualism

环境传播互利共生中宿主特异性基因的选择

基本信息

批准号：
8119661
负责人：
MICHELE Kiyoko NISHIGUCHI
金额：
$ 24.5万
依托单位：
NEW MEXICO STATE UNIVERSITY LAS CRUCES
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-15 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8119661
关键词：
Address Affect Amino Acid Motifs Animals Appearance Architecture Bacteria Biological Assay Cephalopoda Coculture Techniques Collection Complement Conflict (Psychology)DNA Sequence Rearrangement Data Development Plans Disease Ecology Environment Evolution Exposure to Family Funding Gene Cluster Generations Genes Genetic Genome Geographic Locations Goals Gram-Negative Bacteria Grant Growth Housekeeping Gene Human Development Immune response Immune system Infection Influentials Invertebrates Laboratories Life Light Link Measures Methods Microbe Microscopic Modeling Molecular Mollusca Natural Immunity Operon Organ Pathogenesis Pathogenicity Island Pattern Phenotype Physiological Physiology Population Property Research Design Research Methodology Resources Rest Screening procedure Seawater Sequence Analysis Squid Staging Study models Survival Rate Techniques Temperature Testing Time Tissues Variant Vertebrates Vibrio Vibrio cholerae Vibrio fischeri Vibrio parahaemolyticus Vibrio vulnificus Vibrionaceae Virulence Water Work adaptive immunity base fitness loss of function member microbial microorganism interaction mutant mutualism null mutation pressure research study trait

项目摘要

DESCRIPTION (provided by applicant): The mutualistic association between sepiolid squids (Mollusca: Cephalopoda) and their Vibrio symbionts is an experimentally tractable model to study the evolution of animal and bacterial associations at various levels of interaction (genetics, physiology, population ecology). Since symbiotic bacteria are environmentally transmitted to new hosts with every generation, it provides an opportunity to resolve how the ecology of the free-living symbiont affects the architecture of bacterial-host interactions. Bacteria encounter potentially conflicting selective pressures, competing with one another to colonize and persist in the sepiolid light organ, but also competing for scarce resources in the environment outside the squid. A hierarchy of colonization exists, where particular V. fischeri strains out-compete other V. fischeri strains for colonization of their native squid partner, and abiotic factors such as water and temperature can affect the fitness of different strains. Genetic factors that contribute to intra-strain variations in fitness have not been elucidated, and neither have the genetic factors that likely contribute to intra-strain fitness in the environment. The following project will examine how genes that are highly-expressed exclusively in sea water or expressed exclusively in the light organ contribute to bacterial fitness. The present proposal is an extension of the current work in my laboratory, and focuses on four specific goals: i) Characterize environmentally-relevant phenotypes of strains with null mutations in highly-expressed, variable genes. ii) Determine whether a mutant strain complemented with the wild-type operon from the same strain is fit for environmental persistence (free-living) than the same strain complemented with the operon from a different strain. iii) Examine whether symbiotic strains with specific variable loci complemented with the wild-type operon or gene from the same strain are fit for host colonization than the same strain complemented with the operon/gene from a different strain. iv) Measure whether symbiotic genes are found in pathogenicity islands through whole genome comparisons, and demonstrate positive selection of these genes compared to normal housekeeping genes.

描述（由申请人提供）：海泡乌贼（软体动物：头足类）与其弧菌共生体之间的互利关联是一种实验上易于处理的模型，用于研究动物和细菌关联在不同相互作用水平（遗传学、生理学、种群生态学）的进化。由于共生细菌每一代都会在环境中传播到新的宿主，因此它提供了一个机会来解决自由生活的共生体的生态如何影响细菌与宿主相互作用的结构。细菌面临着潜在的相互冲突的选择压力，它们相互竞争在海泡状光器官中定殖并持续存在，但同时也在争夺鱿鱼以外环境中的稀缺资源。存在一定的定殖等级，其中特定的费氏弧菌菌株在其本地鱿鱼伙伴的定殖方面胜过其他费氏弧菌菌株，并且水和温度等非生物因素可以影响不同菌株的适应性。导致品系内适应性变化的遗传因素尚未阐明，可能导致环境中品系内适应性变化的遗传因素也尚未阐明。以下项目将研究仅在海水中高表达或仅在光器官中表达的基因如何促进细菌健康。目前的提案是我实验室当前工作的延伸，重点关注四个具体目标： i) 表征高表达的可变基因中具有无效突变的菌株的环境相关表型。 ii) 确定与来自同一菌株的野生型操纵子互补的突变菌株是否比与来自不同菌株的操纵子互补的同一菌株更适合环境持久性（自由生活）。 iii) 检查具有特定可变位点且由来自同一菌株的野生型操纵子或基因互补的共生菌株是否比由来自不同菌株的操纵子/基因互补的相同菌株更适合宿主定植。 iv) 通过全基因组比较，测量致病岛中是否存在共生基因，并证明这些基因相对于正常看家基因的正选择。