Experimental verification and expression profiles of Xoo sRNAs. Xoo sRNAs were verified and analyzed by Northern blotting. RNA samples were isolated from wild-type (wt) and Δhfq mutant cells cultured in PSA medium at different growth phases. The OD600 values of the cultures are represented by numbers (1: OD600 = 0.5, 2: OD600 = 1.0, 3: OD600 = 1.5, 4: OD600 = 2.0). The DNA probes used in Northern analysis were complementary to the sRNA genes. Arrows indicate the predominant bands. Standard RNA markers are shown on the left. rRNAs served as control for RNA loading and RNA integrities are shown on the bottom panel.