Fig. 1.

A heat-stable antimicrobial peptide, SAMP, identified from HLB-tolerant citrus relatives has bactericidal activity. (A) The expression level of SAMPs in different citrus and citrus relatives was analyzed by qRT-PCR and normalized to Actin. The significant difference is indicated by *P < 0.05 analyzed by t test. (B) SAMPs were detected by Western blot analysis using an anti-MaSAMP antibody in phloem-rich tissue bark peels of Cs, Ma, and Pt. Ponceas staining (PS) was used as the loading control. (C and D) The bactericidal activity of different concentrations (C) or heat pretreatment (D) of MaSAMP solution was examined by Lcr viability/cytotoxicity assays. Streptomycin was used for comparative analysis. The buffer with 10 μM BSA was used as the control. The DMAO (green dye) and EthD-III (red dye) stains the live and dead bacteria, respectively.