Comparative lectin histochemistry with nine lectins was used to quantify galactose and examine its association with the susceptibility in urodelan species. Subsequently, we exposed newts to Batrachochytrium salamandrivorans (Bsal) to assess whether this correlation extends to the individual level. The RCA I lectin emerged as the distinctive biomarker for individual susceptibility. Using RCA, a marker assisted breeding program was set up to evaluate the use of the biomarker in captive breeding programmes.
On newt skin biopsies we determined whether susceptibility to Bsal can be predicted from skin microbiota profiles before exposure. Bsal infection intensity and disease severity cannot be predicted from the diversity, structure, or composition of the skin microbiota. Instead, a strong relation between the population of origin of the experimental newts and their response to Bsal suggests that other factors might rather underpin inter-individual variation in Bsal susceptibility.
To get broader insights into the mechanisms that underly susceptibility to Bsal induced disease a multi-omics approach was used in Bsal exposed newts. Exposure to Bsal affected multiple components of the newts’ immunity, from structural changes in their microbiota and decreased expression of keratin-encoding genes in the epidermis, to inflammatory responses and the development of adaptive immunity in the skin and spleen. Disease susceptibility was positively correlated with increased epidermal and splenic immune responses, reduced basal metabolism and tissue restructuration.
A cell-culture-based model using A6 cells was developed to reproduce the complete life cycle of Bsal. Comparative analysis reveals that Bsal infection closely mirrors responses observed in native salamander skin tissues, validating the A6 cell line as an effective surrogate for in vivo studies. Currently, different gene editing techniques are used to optimize transfection in A6 cells.
