The plant-parasitic nematode Globodera pallida is an obligate biotroph that only reproduces on select species in the Solanum family. The establishment of the feeding site, the syncytium, involves secretion of effectors into the plant cell to combat the plant defense response and facilitate transformation of root cells into the syncytium. Despite the important predicted roles of effectors in the plant−pathogen interactions, the functionality of G. pallida effectors is largely unknown. In this study, we identified and characterized a G. pallida effector protein disulfide isomerase (GpPDI1). GpPDI1 contains two thioredoxin domains that function together to reduce disulfide bonds, as manifested by the nullification of enzymatic activity when either domain is absent. The transcript of GpPDI1 is localized in the dorsal gland of the nematode during the J2 stage. In addition, GpPDI1 can trigger defense-related cell death in Nicotiana benthamiana and tomato (Solanum lycopersicum) leaf tissue and localizes in the plant host cell’s cytoplasm and nucleus when transiently expressed in plant cells. Significantly, the ability of elicitation of cell death is not dependent on the enzymatic activity of GpPDI1 or correlated with the subcellular distribution of GpPDI1, suggesting that a nondisulfide reducing function or structural feature of GpPDI1 is responsible for the recognition by the host immune system to elicit cell death.

植物寄生线虫Globodera pallida是一种专性活体营养生物，仅在茄科的选定物种上繁殖。摄食位点合胞体的建立涉及将效应物分泌到植物细胞中，以对抗植物防御反应并促进根细胞转化为合胞体。尽管效应子在植物与病原体相互作用中具有重要的预测作用，但G. pallida效应子的功能在很大程度上是未知的。在这项研究中，我们鉴定并表征了G. pallida效应蛋白二硫键异构酶 (GpPDI1)。 GpPDI1 包含两个硫氧还蛋白结构域，它们共同发挥作用以减少二硫键，当任一结构域缺失时，酶活性就会消失。在 J2 阶段， GpPDI1的转录本位于线虫的背腺中。此外，GpPDI1可以在本塞姆氏烟草和番茄（ Solanum lycopersicum ）叶组织中触发防御相关的细胞死亡，并且当在植物细胞中瞬时表达时定位于植物宿主细胞的细胞质和细胞核中。值得注意的是，诱导细胞死亡的能力不依赖于 GpPDI1 的酶活性，也不与 GpPDI1 的亚细胞分布相关，这表明 GpPDI1 的非二硫键还原功能或结构特征负责宿主免疫系统的识别以诱导细胞死亡。细胞死亡。