Overexpression of PdPR5-1 in Arabidopsis increases the resistance to Alternaria brassicicola infection.

(A) In vitro inoculation of A. brassicicola on Arabidopsis leaves. Leaves were infected with A. brassicicola spores and incubated in humid conditions for symptom development. The wild type (WT) leaves exhibited clear disease symptoms [yellowing on the margins and spots in the lamina] within 3 days of inoculation, while the PdPR5-1 transgenics significantly delayed the symptom development. (B) When examined using a microscope, uninhibited germination and growth of A. brassicicola spores can be seen on WT leaves (I) while the spores on PdPR5-1-1 leaves showed poor or no germination [II, arrow] further confirming that PdPR5-1 increases resistance to A. brassicicola in transgenic Arabidopsis.