Molecular approaches to study the insect gut symbiotic microbiota at the 'omics' age

Insect gut symbiotic microbiota play essential roles in the growth, development, pathogenesis and environmental adaptation of host insects. The molecular and systems level analysis of insect gut symbiotic microbial community will allow us to discover novel biocatalysts for biomass deconstruction and to develop innovative strategies for pest management. We hereby review the various molecular biology techniques as applied to insect gut symbiont analysis. This review aims to serve as an informative resource for experimental design and research strategy development in the field. We first discuss various strategies for sample preparation and their pros and cons. The traditional molecular techniques like DGGE, RFLP and FISH are covered with respect to how they are applied to study the composition, diversity and dynamics of insect gut symbiotic microbiota. We then focus on the various 'omics' techniques. The metagenome analysis together with the recent advancements in next-generation sequencing will provide enormous sequencing information, allowing in-depth microbial diversity analysis and modeling of pathways for biological processes such as biomass degradation. The metagenome sequencing will also enable the study of system dynamics and gene expression with metatranscriptome and metaproteome methods. The integration of different 'omics' level data will allow us to understand how insect gut works as a system to carry out its functions. The molecular and systems-level understanding will also guide the reverse design of next-generation biorefinery.