TEXT BOX 1 - Traits associated with pathogen susceptibility
Plant traits associated with pathogen resistance, tolerance, and escape
will determine susceptibility of invasive plants to novel pathogen
accumulation. Resistance is the ability of host plants to inhibit or
control pathogen infection, while tolerance is the ability of host
plants to adjust their biomass or fitness post pathogen infection to
reduce impacts, and escape refers to plant avoidance of contact with
pathogens (Veresoglouet al. 2013). Resistance helps host plants prevent or slow down
accumulation of pathogens, and tolerance alleviates reduction in fitness
with pathogen infection. Many plant traits are associated with
resistance and tolerance to pathogens and these can determine long-term
population dynamics including population declines.
Here, we review plant traits associated with pathogen susceptibility,
which may help predict which invasive plants are more susceptible to
novel pathogen attack. We used the TRY database (version 5) to review a
broad range of plant traits and organized them into general categories
of traits (e.g. leaf traits, root traits, growth traits)
(Kattge et al. 2011).
We then searched the literature for references showing how these traits
can influence pathogen susceptibility (Table 1 and Figure 1). Many of
these traits are correlated with one another and can vary along the
plant economic spectrum and along with growth-defense trade-offs;
therefore, it is not always possible to separate these as the direct
drivers of pathogen susceptibility but they can be useful for predictive
purposes (Herms &
Mattson 1992; Reich 2014; Parker & Gilbert 2018). Below, we first
discuss evidence for pathogen resistance, tolerance, and escape with
respect to each of the categories of traits. Next, we review examples of
pathogen accumulation on invasive plants, and finally propose a
framework aimed at explicitly accounting for the relative importance of
traits for pathogen susceptibility.