A novel effector of Aphelenchoides besseyi, AbPFN3, interacts with multiple host proteins to facilitate parasitic nematode and sustain infection in rice

The rice white tip nematode (RWTN) Aphelenchoides besseyi secretes effectors that manipulate the cells of its host plant and help the nematode to successfully parasitize and maintain infection in the host. The number of identified RWTN effectors is limited, and the mechanisms of RWTN effectors interacting with plants are largely unknown. Profilins (PFNs) function as hubs that control a complex network of molecular interactions. To gain full knowledge of PFN3 in plant parasitic nematodes, we identified an effector from A . besseyi named AbPFN3. AbPFN3 is transcriptionally upregulated in the juvenile stage of the nematode. In situ hybridization experiments showed that AbPFN3 transcribed in the nematode esophageal glands. Three AbPFN3-interacting proteins (OsAAC1, OsBAP31 and OsSAUR50) were found in the host plant, with interactions occurring in various locations such as the endoplasmic reticulum, cytoplasm, and plasma membrane. Transgenic analyses showed that the expression of AbPFN3 significantly increased plant height and upregulated the expression of AAC1 and BAP31 while downregulating RGA2 and SAUR50 . This study describes a new effector protein, AbPFN3, secreted by A . besseyi , that interacts with multiple host proteins. These results suggest the important role of AbPFN3 in host defense response and cell development process.