Bacterial spot (BS) is a severe bacterial disease induced by Xanthomonas campestris pv. vesicatoria (Xcv), a pathogen that causes serious damage to pepper growth and yield. It is therefore important to study the mechanisms of pepper resistance to Xcv and to breed and promote Xcv-resistant pepper varieties. However, studies of the responses to Xcv infection in peppers at the protein level are limited. Here, we examined Xcv-induced proteomic changes in leaves of the BS susceptible bell pepper ECW and the resistant bell pepper VI037601 using the isobaric tags for relative and absolute quantitation (iTRAQ)-based protein labeling technology. A total of 6,120 distinct proteins were identified, and there were 1,289 significantly differentially accumulated proteins (DAPs) in ECW and VI037601 leaves after Xcv inoculation. Among these, 339 (250 up- and 89 down-regulated) and 479 (300 up- and 179 down-regulated) DAPs were specifically identified in ECW and VI037601, respectively, with 459 (364 up- and 95 down-regulated) similarly expressed DAPs being shared by ECW and VI037601. Based on bioinformatics analysis, many defense-associated proteins were identified as up-regulated in ECW and VI037601, especially the proteins involved in plant-pathogen interaction, phenylpropanoid biosynthesis, protein processing in the endoplasmic reticulum, and MAPK signaling pathway - plant. Moreover, we evaluated transcript levels of six differentially expressed genes from the iTRAQ results by qRT-PCR. The analysis revealed transcriptional changes that were consistent with the changes at the protein level. This study will provide a valuable resource for understanding the molecular basis of pepper resistance to Xcv infection and for improving the disease resistance of pepper cultivars.

细菌性斑点病 (BS) 是由野油菜黄单胞菌引起的严重细菌性疾病。vesicatoria ( Xcv )，一种对辣椒生长和产量造成严重损害的病原体。因此，研究辣椒抗Xcv机制，培育和推广抗Xcv辣椒品种具有重要意义。然而，在蛋白质水平上对辣椒Xcv感染反应的研究是有限的。在这里，我们检查了Xcv- 使用基于同位素标签的相对和绝对定量 (iTRAQ) 蛋白质标记技术诱导 BS 易感甜椒 ECW 和抗性甜椒 VI037601 叶片的蛋白质组学变化。总共鉴定出 6,120 种不同的蛋白质，并且在Xcv后的 ECW 和 VI037601 叶子中有 1,289 种显着差异积累的蛋白质（DAP）接种。其中，分别在 ECW 和 VI037601 中特异性鉴定了 339 个（250 个上调和 89 个下调）和 479 个（300 个上调和 179 个下调）DAP，类似地有 459 个（364 个上调和 95 个下调）表达了 ECW 和 VI037601 共享的 DAP。基于生物信息学分析，许多防御相关蛋白在 ECW 和 VI037601 中被鉴定为上调，特别是涉及植物-病原体相互作用、苯丙素生物合成、内质网中的蛋白质加工和 MAPK 信号通路的蛋白质 - 植物。此外，我们通过 qRT-PCR 从 iTRAQ 结果中评估了六个差异表达基因的转录水平。分析揭示了与蛋白质水平的变化一致的转录变化。Xcv感染与提高辣椒品种的抗病性。