Data from: Whole plant disease severity is associated with reduced polyphenolic concentrations in lesioned but not green tissue in eelgrass

Plants possess an impressive range of chemical traits to defend themselves
against pathogens. Describing and interpreting these traits can provide
insight into plant resistance to infection and disease progression. To
examine one potentially responsive chemical trait, we measured the
polyphenolic content of green and lesioned tissue from
Labyrinthula-infected seagrass shoots growing in both the field and a
long-term common garden. Infection of eelgrass (Zostera marina) with
wasting disease (Labyrinthula zosterae) forms necrotic lesions on host
tissue and is known to alter host photobiology and secondary metabolite
production. It is common to quantify total polyphenolics as a potential
measure of eelgrass defense against infection, yet there is no clear
evidence that phenolics are a reliable indicator of host response or
immunity. We found that polyphenolic concentrations in green tissue were
not correlated with whole-plant lesion cover, while polyphenolic
concentrations in lesion tissue fell predictably as lesion cover
increased. These results do not support the hypothesis that host plants
respond to L. zosterae infection with a systemic polyphenolic induction as
an immune function; we suggest instead that total phenolic concentrations
in both green and lesioned tissue may be byproducts of other localized
metabolic processes influenced by the presence of necrotic tissue. Further
research is necessary to understand whether plant defenses influence
disease severity in this system.