En-Gen: Bacterial Communication in Microbial Mats: A Metagenomic Approach to Understanding Quorum Sensing Gene Diversity and Expression

细菌世界是地球上最大的未开发生物库，但人们对其成员的功能知之甚少。细菌似乎存在于复杂的社会网络中，依赖于最终影响社区功能的合作和交流。细菌间的交流通常涉及一种称为群体感应（quorum sensing， QS）的细胞间过程，细菌利用这种过程来检测和控制它们对其他细菌的反应。虽然QS是在30多年前被发现的，但人们对它的了解仅限于可以在实验室中生长的不到1%的细菌，因此它的生态学意义尚不清楚。本项目通过研究自然栖息地中QS基因的多样性和表达，以微生物席作为自然栖息地的模型，解决了这一知识缺口。微生物席是地球上最古老、最多样化的生物系统之一，是地球地球化学进化的关键。这些微生物主导的栖息地是了解环境-细胞相互作用以及细胞-细胞相互作用的理想场所。该项目将对微生物垫中的所有细菌进行测序（所谓的“微生物宏基因组”），并寻找可能的QS基因。然后，随着时间和空间的推移，QS基因的表达将被跟踪，以确定是什么因素控制了它们的活动。最后，QS基因的表达将与垫子中的主要细菌群相关，以确定哪些细菌群是垫子中的关键调节者。外展计划包括：(1)在全国知名的动物园举办“看不见的细菌世界”公开展览；(2)在中小学开展“青年基因组科学家”项目；(3)少数民族研究生和本科生参与研究。利用本研究中新发现的QS基因和其他数据库中的QS基因组成的QS表达序列将作为一个社区资源进行开发。这种表达阵列芯片可用于对自然和人类（病原体）系统中细菌-细胞通讯感兴趣的科学家。

The bacterial world is the largest unexplored biological reservoir on Earth, yet little is known about how its members function. Bacteria appear to exist in complex social networks which depend on cooperation and communication that ultimately affect community function. Communication often involves a bacterial cell-to-cell process called quorum sensing (QS), and is used by bacteria to detect and control their responses to other bacteria. While QS was discovered over three decades ago, understanding has been limited to the less than 1% of all bacteria that can be grown in the laboratory so its ecological relevance is not yet clear. This project addresses this knowledge gap through a study of the diversity and expression of QS genes in natural habitats, using microbial mats as the model natural habitat. Microbial mats are one of the oldest and most diverse biological systems on Earth, and have been key to Earth's geochemical evolution. These microbially-dominated habitats are ideal for understanding environment-cell interactions as well as cell-cell interactions. This project will sequence all of the bacteria in the microbial mat (the so-called ' microbial metagenome') and look for possible QS genes. Then QS gene expression will be followed over time and space to determine what factors control their activities. Finally, QS gene expression will be correlated with major groups of bacteria in the mat in order to determine which groups are the key regulators in the mat. The outreach program includes: (1) a public exhibit on the 'Unseen World of Bacteria' at a nationally-renowned Zoo; (2) development of a 'Young Genomic Scientist' program in primary/secondary schools; (3) involvement of minority graduate and undergraduate students in research. A QS expression array with the newly-discovered QS genes from this study and those from other databases will be developed as a community resource. This expression array chip can be used by scientists interested in bacterial cell-cell communication in natural and in human (pathogen) systems.