PSMD4 and infection: The analysis of infection revealed that the Arabidopsis mutants pbe1, a knockout mutant for 20S proteasome [50] and rpn10 with reduced auxin sensitivity [51] were both significantly (P < 0.001) more susceptible to P. cinnamomi compared to their parental background Col-0, with 45.9 and 36.9 pathogen biomass (pg DNA), respectively (Figure 1).