EMBARGOED UNTIL: Monday 5/20, 3 PM MDT

(Symposium Session 139, Paper )

Jiannong Xu
New Mexico State Univesity
Las Cruces, NM, United States
Phone: 575 646-7713
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Mosquitoes are insect vectors responsible for the transmission of devastating parasitic and viral infections including malaria, dengue haemorrhagic fever, yellow fever, West Nile fever, and other diseases caused by arboviruses. An understanding of mosquito biology is essential for disease surveillance as well as for designing and implementing effective measures for disease control and prevention. Mosquito gut harbors a complex microbial community, these microbial inhabitants makes a significant contribution to the mosquito genetic repertoire. During the evolution mosquitoes and associated microbes have established a symbiotic dependency, in which the mosquito and microbial genes aggregated into a dynamic composite. This relationship profoundly affects various mosquito life traits, including fecundity and immunity. The mosquito microbiome study is to develop a strategy to understand the microbial components in the mosquito genetic landscape and how they influence mosquito physiology and disease transmission. The long term goal is to exploit the knowledge of mosquito gut microbiome to intentionally manipulate the microbiome to assist mosquito to fight pathogens, or reduce mosquito fitness to downsize mosquito populations.

This work was presented at the 2013 ASM General Meeting, in the session “Discoveries in Symbiosis in the "omics" Age”, on May 20, 2013 at Denver, CO. The work was conducted mainly by the Xu lab in Biology Department, College of Arts and Sciences, New Mexico State University. The collaborators include Dr. Guiyun Yan in Ecology & Evolutionary Biology, School of Biological Sciences University of California, Irvine, Dr. Hongmei Jiang in Department of Statistics, Northwestern University, and Dr. Lingling An, Department of Agricultural and Biosystems Engineering, University of Arizona, and Dr. Ingrid Faye in Department of Genetics, Microbiology and Toxicology, Stockholm University, Sweden. The field mosquitoes were sampled in Kenya, Africa, and Shandong, China. The lab work was done at the Xu lab in Las Cruces, New Mexico, USA. The work was funded by HIN to Xu, NIH to Yan, NSF to An, Jiang and Xu.

Mosquito microbiome study is a conceptual extension of mosquito genome project. We are focusing on the metagenomic characterization and functional configuration of the mosquito gut microbiome. We tried to address three related questions: Who’s out there in the community (composition)? What can they do (gene content) ? What are they doing in a certain context (actively transcribed genes)? The constituent microorganisms were first profiled by bacterial 16S ribosomal RNA gene tag using pyrosequencing technology. The data revealed dynamic microbiota across mosquito life history. The microbial community structure is different between larvae and adults. Intriguingly, blood feeding changes the composition, and enteric bacteria are favored in the blood fed guts. The gut microbes are not random assemblages, a group of core inhabitants were identified, they belong to four bacterial families, Enterobacteriaceae, Pseudomonadaceae, Flavobacteriaceae and Acetobacteraceae. Next, we characterized metagenomic gene content by shot gun sequencing gut microbial community. From 6Gbp sequencing data, we generated a 37Mbp reference using de novo assembly, which contains ~ 29,000 predicted genes, 42% of these genes were assigned into 703 functional subsystems. Metabolic reconstruction predicted 5301 model genes, which are involved in 1658 reactions and 1266 compounds. The presence of polysaccharide utilization loci (PULs), large capacity of antibiotic resistance genes and oxidative stress defense genes provide insights into that how the gut microbiome is shaped and maintained and how they respond to the diet change between sugar and blood meals. Finally, the metagenomic reference was used for mapping RNAseq sequencing reads to investigate context-dependent gene expression in the microbial community. The data provide an informative glimpse of mosquito gut microbiome in terms of structural and functions, which will help deciphering the symbiotic relationship between the microbiome and the mosquito host.