Astrobiology Science Conference 2017 (LPI Contrib. No. 1965) 3581.pdf LACK OF CONGRUENCE BETWEEN THE PHYLOGENIES OF ZOOTERMOPSIS TERMITES AND THEIR MICROBIAL SYMBIONTS: EVIDENCE OF HORIZONTAL TRANSMISSION? S. J. Taerum1 and G. H. Gile1, 1School of Life Science, Arizona State University, [email protected] Introduction: Mutualistic microbes have dramati- Trichonympha collaris, Trichonympha postcylindrica, cally altered the niche breadth of plants, animals and and Trichonympha sphaerica. We assessed the gut fungi. This has driven and shaped the evolution of both protist communities of the other three Zootermopsis multicellular hosts and associated microbes in many taxa and compared with that of Z. angusticollis. associations. A common hypothesis in symbiosis theo- We collected the four Zootermopsis taxa, and iso- ry is that vertically inherited mutualistic microbes lated individual parabasalid cells from the termite guts. should diverge and speciate along with their hosts, We then used a combination of Sanger sequencing and resulting in the hosts and microbes having congruent morphological assessments to identify the protist spe- phylogenies [1]. However, incongruencies are fre- cies. In addition, we conducted amplicon sequencing quently observed because of horizontal transmission of of the whole termite guts using Illumina high- microbes between related species. More knowledge on throughput sequencing. the interplay between vertical and horizontal transmis- Based on sequence data, the gut protist communi- sion is required for a better understanding of host- ties of Z. nevadensis nuttingi and Z. nevadensis ne- microbe coevolution. vadensis appeared to be identical to that of Z. angusti- Lower termites are an ideal group of organisms for collis. Zootermopsis laticeps contained three species the study of host-microbe symbiosis and coevolution. (one of Trichomitopsis and two of Trichonympha) that These insects primarily feed on wood which contains have not yet been described. recalcitrant materials such as cellulose. Lower termites The similarities in protist communities between Z. depend in part on protists in the groups Parabasalia angusticollis, Z. nevadensis nevadensis, and Z. ne- (i.e., “parabasalids”) and Oxymonadida (“oxy- vadensis nuttingi suggest that horizontal symbiont monads”) to digest the cellulose [2]. These symbionts transmission may occur between these species, possi- inhabit the hind guts of their temite hosts, and are both bly facilitated by overlapping ranges as well as hybrid- obligate and vertically transmitted. Cocladogenesis ization between the species and subspecies. The differ- between termites and their mutualist protists has been ent community in Z. laticeps may be due to geograph- demonstrated within termite families [e.g., 3]. Howev- ical isolation from the other Zootermopsis species, as er, coevolutionary patterns have never been closely well as differences in habitat conditions. Further re- examined within a termite genus. Here, we tested for search is required to better understand the evolutionary evidence of host-microbe coevolution between termites history of the termite genus and its associated mi- in the genus Zootermopsis and their protist symbionts. crobes. The genus Zootermopsis contains four taxa (three References: [1] Bright M. and Bulgheresi S. species, one of which has been divided into two sub- (2010) Nat. Rev. Microbiol., 8, 218–230. [2] Inoue T. species), all of which occur only in western North et al. (2000) Termites: Evolution, Sociality, Symbioses, America: Zootermopsis nevadensis nevadensis Ecology, 275-288. [3] Noda S. et al. (2007) Mol. Ecol., Zootermopsis nevadensis nuttingi, Zootermopsis an- 16, 1257–1266. [4] Thorne B. L. et al. (1993) Ann. gusticollis, and Zootermopsis laticeps [4]. The ranges Entomol. Soc. Amer. 86, 532-544. [5] Tai V. et al. of Z. nevadensis nuttingi and Z. angusticollis overlap (2013) Plos One 8, e58727. almost entirely, running along the west coast of North America from the Pacific Northwest down to southern California. Most of the range of Z. nevadensis ne- vadensis is east of the Sierra Nevada, although the range slighty overlaps with those of Z. nevadensis nut- tingi and Z. nevadensis nevadensis in northern and southern California. Finally, the range of Z. laticeps is from central Arizona to western Texas. Until the present study, only the protist community of Z. angusticollis was closely examined [5]. In that study, the authors identified seven parabasalid species: Trichomitopsis minor, Trichomitopsis parvus, Tri- chomitopsis termopsidis, Trichonympha campanula, .