Virus-induced gene silencing of PvNod22 in common bean plants mediated by the BPMV-RNA2 vector. Silencing of PvNod22 induces necrotic phenotypes in 3 week-old common bean plants (upper panel, VIGSNod22). Relative levels of expression of Nod22 transcript in common bean treated plants (lower panel). Expression levels of Nod22 transcript were determined by qRT-PCR at 2 weeks post inoculation. Mock, mock-inoculated plants; vector, empty vector-inoculated plants; VIGSNod22 P1-P3, Nod22 silenced common bean plants. The primers nod22-ext., nod22-int., and PvEf1-α (Table I) were used in this experiment to determine the Nod22 transcript abundance. Bars represent the mean value of three biological and technical replicates. Error bars represent standard error. P-values < 0.01.