UNESP, Instituto de Biociências, Departamento de Genética, Botucatu, SP, Brazil.
Plant Sci. 2012 Aug;191-192:35-42. doi: 10.1016/j.plantsci.2012.04.012. Epub 2012 Apr 28.
Class III peroxidases (Prxs) are enzymes involved in a multitude of physiological and stress-related processes in plants. Here, we report on the characterization of a putative peroxidase-encoding gene from Coffea arabica (CaPrx) that is expressed in early stages of root-knot nematode (RKN) infection. CaPrx showed enhanced expression in coffee roots inoculated with RKN (at 12 h post-inoculation), but no significant difference in expression was observed between susceptible and resistant plants. Assays using transgenic tobacco plants harboring a promoter-β-glucuronidase (GUS) fusion revealed that the CaPrx promoter was exclusively active in the galls induced by RKN. In cross sections of galls, GUS staining was predominantly localized in giant cells. Up-regulation of GUS expression in roots of transgenic plants following RKN inoculation was observed within 16 h. Moreover, no increase in GUS expression after treatment with jasmonic acid was detected. Altogether, these results point to a putative role of this peroxidase in the general coffee response to RKN infection.
III 类过氧化物酶（Prxs）是参与植物中多种生理和应激相关过程的酶。在这里，我们报告了一种来自咖啡（Coffea arabica）的假定过氧化物酶编码基因（CaPrx）的特征，该基因在根结线虫（RKN）感染的早期阶段表达。CaPrx 在接种 RKN 的咖啡根中表达增强（接种后 12 小时），但在感病和抗病植物之间未观察到表达的显著差异。使用携带启动子-β-葡萄糖醛酸酶（GUS）融合的转基因烟草植物进行的测定表明，CaPrx 启动子仅在 RKN 诱导的瘿瘤中活性。在瘿瘤的横切片中，GUS 染色主要定位于巨型细胞中。在接种 RKN 后，转基因植物根部的 GUS 表达在 16 小时内上调。此外，未检测到在处理茉莉酸后 GUS 表达增加。总的来说，这些结果表明该过氧化物酶在咖啡对 RKN 感染的一般反应中可能具有作用。
