Transcriptomics reveal immune downregulation of newts overwhelmed by chytrid co‐infection

Abstract

What happens when two emergent diseases infect the same host? In a From the Cover article in this issue of Molecular Ecology, McDonald et al. (2020) compare transcriptomic responses to co‐infection by the two chytrid fungi in the skin, liver and spleen of Eastern newts (Notophthalmus viridescens). Novel molecular tools, such as high‐throughput DNA sequencing for genome discovery and transcriptomics, have revolutionized our understanding of host–pathogen interactions and disease ecology (Güimil et al. 2005; Rosenblum et al. 2012). For example, epidemiologists are using genomic data to track the spread of the emergent SARS‐CoV‐2 in real time, both locally and globally. RNA sequencing (RNA‐Seq) is routinely employed to study response to disease in humans, improving disease diagnostics, profiling and development of intervention strategies. Transcriptomic profiles may be particularly informative for emergent diseases, whose pathologies and effect on host phenotype are poorly known. Fungal pathogens increasingly threaten a variety of wild and domesticated organisms (Fisher et al. 2012), and two chytrid fungi attacking amphibians are causing one of the worst losses of vertebrate biodiversity ever recorded (Scheele et al. 2019).

Host gene expression in wildlife disease: making sense of species‐level responses

“…In particular, studies of host gene expression can provide a tissue‐specific assay of the genes and cellular pathways involved in pathogen response (Blanchong et al, 2016; Ekblom & Galindo, 2011; Jenner & Young, 2005; Wang et al, 2009). This approach seems tailor‐made for parsing the molecular basis of species‐specific wildlife disease progression (Barreiro & Tung, 2012; DeCandia et al, 2018; Greenwood et al, 2016; Gupta et al, 2020; Shepack & Catenazzi, 2020; Zamudio et al, 2020): presumably, the gene expression responses of disease‐resistant hosts following pathogen exposure should reveal the molecular processes that distinguish their favourable disease outcome from those of less fortunate species. Candidate genes can then be targeted to further investigate specific modes of adaptation (Shultz & Sackton, 2019).…”

Differential Spleen miRNA Expression Profile of Beagle Dogs Infected with Toxocara canis

“…However, the mechanisms of host- T. canis interactions are not fully clear, such as how T. canis evades the host’s immune surveillance. The understanding of pathogen–host interactions and disease ecology is changing with the advent of new molecular tools, such as high-throughput transcriptomics sequencing [ 4 ]. Large sets of novel and known microRNAs (miRNAs) and their target genes involved in innate and adaptive immune responses have been discovered following the rapid advancement of next-generation sequencing (NGS) techniques [ 5 ].…”