Pratylenchus coffeae Effector PcENG2 Targets the Maize Chitinase ZmCHI5 to Promote Parasitism.

Pratylenchus coffeae, a damaging root-lesion nematode, secretes effectors to manipulate host processes and promote parasitism. Here, we characterize PcENG2, a β-1,4-endoglucanase localized in the nematode esophageal gland cells and secreted during infection. PcENG2 expression is upregulated during the early parasitic stage of P. coffeae. PcENG2 promotes cell wall and callose degradation, as demonstrated by immunolocalization and immunoelectron microscopy. It also suppresses host reactive oxygen species (ROS) production and enhances susceptibility to P. coffeae when ectopically expressed in Arabidopsis. PcENG2 directly interacts with maize (Zea mays L.) chitinase, a key defense-related protein. This interaction suppresses chitinase enzymatic activity and protects nematode eggs from degradation. Virus-induced gene silencing (VIGS) demonstrated that ZmCHI5 is essential for broad-spectrum nematode resistance in maize. Collectively, these findings identify PcENG2 as a key effector that modulates host immunity to promote P. coffeae infection.