Fig. 4

CsSAG12s increase in abundance but not activity in infected citrus. a Diagram illustrating the experimental approach for detecting abundance and activity of CsPLCPs in healthy and infected Navel oranges (C. sinensis) from a Texas grove using mass spectrometry. b Abundance and protease activity of six PLCPs belonging to four subfamilies in citrus leaf samples. Leaf tissue was ground in Tris buffer and divided into two to assess abundance and activity. PLCP abundance was tested using an in-solution digest coupled with mass spectrometry. For activity, the addition of DCG-04 permits the labeling of active PLCPs. Active PLCPs were captured and identified by streptavidin IP coupled with mass spectrometry. Mean ± standard error of three replicates is shown. Asterisks (*) indicate statistically significant differences based on the two-tailed Student’s t-test. N.d = no difference, p < 0.05 = *, p < 0.01 = **, p < 0.001 = ***. The gene IDs are CsXBCP3 (orange1.1g012960m), CcXCP1 (Ciclev10001665m), CsAALP (orange1.1g036910m), CcSAG12-1 (Ciclev10005334m), CsSAG12-3 (orange1.1g018958m), and CsSAG12-4 (orange1.1g019063m). Jessica Franco created the citrus images in panel a by hand for use in this paper