2.2 Root zone warming enhances tomato resistance to Xcv disease
To determine whether RZW can induce resistance to additional classes of pathogens in tomato, as was previously reported in basil (Elad et al., 2017, 2016a), we examined the effect of RZW on pathogenesis of the hemibiotrophic pathogenic bacteria Xcv , the causative agent of bacterial spot disease in many plant species (Moss et al., 2007). Wild type (WT) M82 tomato plants were treated with 48 h RZW and allowed to recover for 3 days or 5 days prior to Xcv infection (Figure 4 ), and disease progression was measured using colony forming unit (CFU) count as described in the methodology section. Disease was assessed 3 days after pathogen inoculation. As we found forBc , RZW significantly decreased disease levels of Xcv in both Brigade (Figure 4a ) and M82 (Figure 4b ) cultivars. Once again, the disease reduction is due to systemic effects generated in the roots, which provide disease protection in the plant shoot.