Transcription Factor Pso9TF Assists Xinjiang Wild Myrobalan Plum (Prunus sogdiana) PsoRPM3 Disease Resistance Protein to Resist Meloidogyne incognita

The root-knot nematode (Meloidogyne incognita) causes huge economic losses in the agricultural industry throughout the world. Control methods against these polyphagous plant endoparasites are sparse, the preferred one being the deployment of plant cultivars or rootstocks bearing resistance genes against Meloidogyne species. Our previous study has cloned one resistance gene, PsoRPM3, from Xinjiang wild myrobalan plum (Prunus sogdiana). However, the function of PsoRPM3 remains elusive. In the present study, we have investigated the regulatory mechanism of PsoRPM3 in plant defense responses to M. incognita. Our results indicate that fewer giant cells were detected in the roots of the PsoRPM3 transgenic tobacco than wild tobacco lines after incubation with M. incognita. Transient transformations of full-length and TN structural domains of PsoRPM3 have induced significant hypersensitive responses (HR), suggesting that TIR domain might be the one which caused HR. Further, yeast two-hybrid results revealed that the full-length and LRR domain of PsoRPM3 could interact with the transcription factor Pso9TF. The addition of Pso9TF increased the ROS levels and induced HR. Thus, our data revealed that the LRR structural domain of PsoRPM3 may be associated with signal transduction. Moreover, we did not find any relative inductions of defense-related genes PsoEDS1, PsoPAD4 and PsoSAG101 in P. sogdiana, which has been incubated with M. incognita. In summary, our work has shown the key functional domain of PsoRPM3 in the regulation of defense responses to M. incognita in P. sogdiana.