Regulation of BAK1CTF production. A, Production of BAK1CTF in pBAK1::BAK-GFP transgenic plants upon Pst hrcC infection. Four-week-old soil-grown Arabidopsis pBAK1::BAK-GFP transgenic plants were hand-inoculated with Pst hrcC at 5 × 105 cfu. Total proteins from inoculated leaf extracts were analyzed by western blot (WB) with an α-GFP antibody. B, Production of BAK1CTF in wild-type plants upon infections. Four-week-old soil-grown Arabidopsis Col-0 plants were hand-inoculated with Pst hrcC at 5 × 105 cfu or 1 μM flg22. Total proteins from inoculated leaf extracts were analyzed by WB with an α-BAK1 antibody. C, Developmental regulation of BAK1CTF production. Total proteins extracted from Arabidopsis 35S::BAK1-HA transgenic plants at different growth stages from 8 through 35 d past germination (dpg) on 1/2 MS plates were analyzed by WB with an α-HA antibody. D, BAK1CTF production in different tissues. Total proteins extracted from different tissues of 2-month-old soil-grown 35S::BAK1-HA transgenic plants were analyzed by WB with an α-HA antibody. The above experiments were repeated three times with similar results. Hpi, hours post inoculation; F, flowers, S, stem; CL, cauline leaves; RL, rosette leaves; R, roots.