Meta‑analysis cum machine learning approaches address the structure and
biogeochemical potential of marine copepod associated bacteriobiomes
Abstract
Copepods are the dominant members of the zooplankton community and the
most abundant form of life. It is imperative to obtain insights into the
copepod-associated bacteriobiomes (CAB) in order to identify specific
bacterial taxa associated within a copepod, and to understand how they
vary between different copepods. Analysing the potential genes within
the CAB may reveal their intrinsic role in biogeochemical cycles. For
this, machine-learning models and PICRUSt2 analysis were deployed to
analyse 16S rDNA gene sequences (approximately 16 million reads) of CAB
belonging to five different copepod genera viz., Acartia spp., Calanus
spp., Centropages sp., Pleuromamma spp., and Temora spp.. Overall, we
predict 50 sub-OTUs (s-OTUs) (gradient boosting classifiers) to be
important in five copepod genera. Among these, 15 s-OTUs were predicted
to be important in Calanus spp. and 20 s-OTUs as important in
Pleuromamma spp.. Four bacterial s-OTUs Acinetobacter johnsonii,
Phaeobacter, Vibrio shilonii and Piscirickettsiaceae were identified as
important s-OTUs in Calanus spp., and the s-OTUs Marinobacter,
Alteromonas, Desulfovibrio, Limnobacter, Sphingomonas,
Methyloversatilis, Enhydrobacter and Coriobacteriaceae were predicted as
important s-OTUs in Pleuromamma spp., for the first time. Our
meta-analysis revealed that the CAB of Pleuromamma spp. had a high
proportion of potential genes responsible for methanogenesis and
nitrogen fixation, whereas the CAB of Temora spp. had a high proportion
of potential genes involved in assimilatory sulphate reduction, and
cyanocobalamin synthesis. The CAB of Pleuromamma spp. and Temora spp.
have potential genes accountable for iron transport.