Species specific marker genes for systemic defence and stress responses to leaf wounding and flagellin stimuli in hybrid aspen and silver birch

In Northern Europe, climate warming is driving the northward expansion of deciduous tree species such as aspen and silver birch. At the same time, it is intensifying biotic stresses from pests and pathogens, necessitating the development of innovative biotechnological approaches to enhance forest resistance and resilience. However, progress in understanding the genetic basis of stress responses in temperate deciduous trees remains limited, largely due to the absence of reproducible laboratory model systems and well-characterized molecular stress markers. In this study, we aimed to identify and validate known plant defense gene markers to support future functional research on stress responses in hybrid aspen and silver birch. We used sequence mining and phylogenetic analyses to identify homologues of biotic stress-response genes in the genomes of both tree species. We then employed in vitro propagated tree clones to test defense gene activation in distal leaves following systemic signal induction via leaf wounding and bacterial flagellin application, assessed at 4- and 24- hours post-treatment. We present a short communication of a novel in vitro methodological approach for the preliminary evaluation of molecular responses to systemic signaling in birch and aspen. The findings represent a methodological advancement for studies of systemic signalling and molecular defense responses in ecologically and economically important tree species and offer a pipeline for gene homologue discovery for the future research on tree-microbe interactions and resilience.