drench-treated plants after the second inoculation. This elevated
PR2 expression after the ASM application was previously described
by Francis et al. (2009).
Enhanced callose deposition in Hx soil drench-treated plants
after the first inoculation was correlated with the CALS1 gene
expression. This accumulation was not observed in the Hx sprayand
ASM-treated plants. Callose acts as a physical barrier that
concentrates antimicrobial compounds at fungal penetration sites
(Huang et al., 2006). Lee et al. (2009) proposed that callose also
contributes to resistance against invading bacterial pathogens by
providing a physical barrier. Recently,