In an era marked by rising global temperature, understanding the complex interplay between organisms and their environment is vital for informed conservation efforts. Redband trout ( Oncorhynchus mykiss gairdneri), a subspecies of rainbow trout, holds a distinct ecological niche within the diverse landscapes of Northwest America. Redband trout is inherently adapted to coldwater habitats, however, the species faces a challenge with the escalating global temperatures associated with climate change.
Considering the challenges posed by global warming on coldwater habitats, particularly affecting species like the redband trout, there is a critical need to understand the holistic biological interactions that might contribute to its overall fitness. Currently, research on Redband trout as a holobiont unit is limited. Consequently, our study focused on analyzing the environmental and genetic factors that shape microbial composition and examine their impact on microbial functions, which in turn could affect the overall fitness of redband trout to warmer temperatures. We conducted two seasonal field samplings (summer and winter) and a common-garden study (Fig. 1) , where trout from disparate thermal habitats were acclimated to identical temperature regimens (constant: 15°C, 18°C, 21°C, and diel: 13-17°C, 16-20°C, 19-23°C). Samples included mucosa from gills, skin, and digesta of redband trout, along with sediment and water samples from desert, cool montane, and cold montane creeks, as well as the common-garden system.
Figure 0: Temperature profiles of common-garden RAS setup
To investigate bacterial and archaeal taxonomic information ( alpha and beta diversity) , 16S rRNA sequencing was utilized, and the data was analyzed using DADA2 and Phyloseq . Whereas Nanopore sequencing was carried out to reveal microbial functions and relative abundance of Bacterial and non-Bacterial sequences . GTseq was used to genotype SNPs in individual fish, where neutral and adaptive markers were analyzed based on the habitat the trout was from. Our research explores the interaction between redband trout and its microbiome as a possible mechanism contributing to variations in traits, from genetic makeup to observable characteristics, in response to changes in temperature. The forthcoming results will focus on comparing microbial compositions (bacterial and non-bacterial) between different tissues and sites, encompassing both the host and the environment. Furthermore, the investigation will parse the gene by environment (GxE) regulation, integrating insights from both field and laboratory studies. Additionally, the study will explore pathogen levels along thermal gradients, shedding light on potential associations between microbial communities and temperature variations.