Investigations into the roles of symbiotic treponemes in the higher termite Italic: Nasutitermes takasagoensis.
1RIKEN BRC JCM, 2IIB Liverpool univ, 3RIKEN CSRS BMEP, 4Tokyo Institute Tech
Diverse Italic: Treponema species form the bulk of the higher termite Italic: Nasutitermes takasagoensis gut consortia, these treponemes in collaboration with the rest of the gut community efficiently digest the woody biomass that makes up the termites diet and converts this to acetate. Few treponemes have been cultured, and only those isolated from lower termites (basal lineages present with gut protists) have been studied in depth. In higher termites culture independent techniques have been explored to study these organisms and the possible roles they play in this nutritional symbiosis. Here we present through the culture-independent techniques of single cell genomics and metatranscriptomics _ a unique perspective of the diversity of treponemes isolated from Italic: N. takasagoensis.
Through the use of fluorescence activated cell sorting we isolated Italic: Treponema single cells and after whole genome amplification using Phi29 DNA polymerase we sequenced the individual cells genomes on the Illumina MiSeq platform. Total RNA from whole gut contents was also isolated, depleted of ribosomal RNA and then sequenced on the MiSeq.
The individual treponemes were assigned to 9 out of the 10 phylogenetically defined clusters of the higher termite treponeme groups within the expansive Italic: Treponema cluster I using 16S rRNA gene sequences. The genomes contained multiple glycosyl hydrolases that clustered within groups and those with novel structures and domains. Genes involved in reductive acetogenesis and nitrogen utilization were also found in the genome assemblies and supported by the metatranscriptome data, shedding light on the putative functions and the evolution of these groups within the termite nutritional symbiosis.