Bacteria-Mediated Coral Disease Resistance

细菌介导的珊瑚病抗性

• 批准号: 0648116
• 负责人: Farooq Azam
• 金额: $ 36.5万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0648116&HistoricalAwards=false
• 关键词: Bacteria; Mediated; Coral; Disease; Resistance

Corals are increasingly threatened by disease induced mortality, and the risk of infection may be increased by elevated sea surface temperature either by promoting pathogen growth or virulence, reducing host resistance to infection, or a combination of both. This project will investigate the hypothesis that coral-associated bacteria mediate disease resistance through bacteria-bacteria interactions and this resistance mechanism is altered by elevated temperatures. The project tests three hypotheses related to the bacteria mediated resistance hypothesis: (1) Antagonistic interactions among coral-associated bacteria limit pathogen colonization and proliferation within the mucus layer. Antagonistic interactions among bacteria affect the diversity and spatial distribution of bacteria in marine pelagic and epibiotic communities, in part by preventing some bacteria from entering the established community. Analogous processes in the coral surface mucus layer will be examined with laboratory assays and in situ experiments using cultivable bacteria, combined with fluorescent in situ hybridization, phylotype-specific PCR, and denaturing gradient gel electrophoresis to assess non-cultivable bacteria. (2) Elevated temperature alters bacterial growth rates and bacteria-bacteria antagonism, facilitating pathogen colonization and proliferation. Growth rates are a fundamental force influencing bacteria community dynamics and can influence the relative abundance of phylotypes within a community. Temperature can affect growth rate as well as bacterial antibiotic production, thus altering the outcome of bacteria-bacteria interactions. Culture-dependent and -independent techniques will be used to explore bacteria-bacteria interactions on corals exposed to various temperature treatments and temporal samples of permanently tagged corals on the reef. (3) Other members of the coral-associated microbial community (e.g., eukaryotic grazers, viruses) impact the abundance and dynamics of coral-associated bacteria, potentially altering disease resistance. The coral mucus habitat contains not only prokaryotes but eukaryotic grazers and viruses. These predators strongly influence bacteria communities in the water column and their role is proposed to be analogous in the coral mucus layer. The intellectual merit of this project lies in the integration of coral reef ecology and microbial ecology to address fundamental questions regarding coral health and disease. Both culture-dependent and-independent techniques will be utilized to examine the ecological interactions of cultivable bacteria and assess dynamics of the whole community. The work is timely and imperative given the declining status of coral reefs and predictions of future decline. The broader impacts of this project include integration of research and education by developing seminars for the Professional Development Series for Education Staff at the Birch Aquarium at Scripps (La Jolla, CA). Participation of under-represented groups will be encouraged through 1) international coral disease workshops in the Philippines and East Africa facilitated in conjunction with the World Bank / Global Environment Fund Coral Reef Targeted Disease Research Group, 2) Mentoring of undergraduate students from the University of Guam, and 3) Developing a curriculum to engage minority high school students with ocean sciences and mentoring a team of minority high school students for the National Ocean Sciences Bowl.

珊瑚越来越受到疾病引起的死亡的威胁，海洋表面温度升高可能会增加感染的风险，因为这会促进病原体的生长或毒性，降低宿主对感染的抵抗力，或两者兼而有之。该项目将研究珊瑚相关细菌通过细菌-细菌相互作用介导疾病抗性的假设，这种抗性机制会因温度升高而改变。该项目测试了与细菌介导的抗性假说有关的三个假设：（1）珊瑚相关细菌之间的拮抗相互作用限制了病原体在粘液层内的定植和增殖。细菌之间的拮抗相互作用影响海洋浮游生物和表生生物群落中细菌的多样性和空间分布，部分原因是阻止某些细菌进入已建立的群落。珊瑚表面粘液层中的类似过程将通过实验室分析和使用可培养细菌的原位实验进行检查，并结合荧光原位杂交，PCR和变性梯度凝胶电泳来评估不可培养的细菌。(2)升高的温度改变细菌生长速率和细菌-细菌拮抗作用，促进病原体定殖和增殖。生长速率是影响细菌群落动态的基本力量，并且可以影响群落内细菌类型的相对丰度。温度可以影响生长速率以及细菌抗生素的产生，从而改变细菌-细菌相互作用的结果。将使用依赖于培养和独立的技术来探索暴露于各种温度处理的珊瑚和珊瑚礁上永久标记的珊瑚的时间样本上的细菌-细菌相互作用。(3)珊瑚相关微生物群落的其他成员（例如，真核食草动物、病毒）影响与珊瑚有关的细菌的丰度和动态，可能改变抗病能力。珊瑚粘液栖息地不仅包含原核生物，还包含真核食草动物和病毒。这些捕食者强烈影响水柱中的细菌群落，它们的作用被认为在珊瑚粘液层中类似。该项目的智力价值在于将珊瑚礁生态学和微生物生态学结合起来，以解决有关珊瑚健康和疾病的基本问题。这两个文化依赖和独立的技术将被用来检查可培养细菌的生态相互作用，并评估整个社区的动态。鉴于珊瑚礁的状况不断下降，而且预测今后将出现衰退，这项工作是及时和必要的。该项目的更广泛的影响包括研究和教育的整合，为教育工作人员的专业发展系列在斯克里普斯（拉霍亚，CA）的桦树水族馆开发研讨会。将通过以下方式鼓励代表性不足的群体参加：1）与世界银行/全球环境基金珊瑚礁目标疾病研究小组一起，在菲律宾和东非举办国际珊瑚病讲习班，2）指导关岛大学的本科生，和3）开发一个课程，让少数民族高中生参与海洋科学，并为国家海洋科学碗辅导一组少数民族高中生。