Phylogenetic analysis of the iconic termite symbiont, Trichonympha: Novel species and implications for protist sharing

Description
Protist-dependent termites rely on a mutually obligate symbiosis with populations of protists that colonize the hindgut to digest lignocellulose. Protists are transmitted vertically amongst termite colonies so that each member of a termite species shares protist symbionts with its nestmates.

Protist-dependent termites rely on a mutually obligate symbiosis with populations of protists that colonize the hindgut to digest lignocellulose. Protists are transmitted vertically amongst termite colonies so that each member of a termite species shares protist symbionts with its nestmates. These protist populations are therefore thought to be specific to their host and may serve as an indicator of the evolution and diversification of both termites and protists. However, evolutionary signals may be misinterpreted or interrupted if protists are misidentified, lost, or transferred between termite species. The protist genus Trichonympha is one such taxon whose constituent species deviate from typical phylogenetic patterns of vertical inheritance. In this study, light microscopy, single cell isolation, and 18S sequencing were used to determine the morphology and phylogeny of Trichonympha from Reticulitermes spp., resulting in the discovery of 2 novel species and the revision of the longstanding species, Trichonympha agilis. These results suggest the importance of phylogeny over morphology in species determination, and the confirmation that multiple termite species host the same protist symbionts.
Date Created
2024-05
Agent

Analysis of Oxymonas Diversity in Cryptotermes brevis Using 18S Sequencing

Description

Oxymonas is a genus of Oxymonad protist found in the hindgut of drywood termites (family Kalotermitidae). Many genera of drywood termites are invasive pests globally. The hindgut microbiome of Cryptotermes brevis, the West Indian drywood termite, has not been described

Oxymonas is a genus of Oxymonad protist found in the hindgut of drywood termites (family Kalotermitidae). Many genera of drywood termites are invasive pests globally. The hindgut microbiome of Cryptotermes brevis, the West Indian drywood termite, has not been described in detail, and only one published sequence exists of Oxymonas from C. brevis. This study aims to analyze Oxymonas sequences in C. brevis from whole gut genetic material, as well as to dissect its place in phylogenetic trees of Oxymonas and how it fits into specific and evolutionary patterns. To amplify the 18S rRNA gene Oxymonas from C. brevis, the MasterPure DNA extraction kit was used, followed by PCR amplification, followed by agarose gel electrophoresis, followed by purification of the resulting gel bands, followed by ligation/transformation on to an LB agar plate, followed by cloning the resulting bacterial colonies, and topped off by colony screening. The colony screening PCR products were then sequenced in the Genomics Core, assembled in Geneious, aligned and trimmed into a phylogenetic tree, along with several long-read amplicon sequences from Oxymonas in other drywood termites. All whole gut sequences and one amplicon from C. brevis formed a single clade, sharing an ancestor with a sister clade of Oxymonas sp. from C. cavifrons and Procryptotermes leewardensis, but the other long-read fell into its own clade in a different spot on the tree. It can be conjectured that the latter sequence was contaminated and that the C. brevis clones are a monophyletic group, a notion further corroborated by a distantly related clade featuring sequences from Cryptotermes dudleyi, which in turn has a sister taxon of Oxymonas clones from C. cavifrons and P. leewardensis, pointing toward a different kind of co-diversification of the hosts and symbionts rather than cospeciation.

Date Created
2023-05
Agent