Background: Plant root-knot nematode (RKN) disease is a serious threat to agricultural production across the world. Meloidogyne incognita is the most prominent pathogen to the vegetables and cash crops cultivated. Arachis hypogaea can effectively inhibit M. incognita, but the underlying defense mechanism is still unclear. Methods: In our study, the chemotaxis and infestation of the second-stage juveniles (J2s) of M. incognita to A. hypogaea root tips were observed by the Pluronic F-127 system and stained with sodium hypochlorite acid fuchsin, respectively. The transcriptome data of A. hypogaea roots with non-infected or infected by J2s were analyzed. Results: The J2s could approach and infect inside of A. hypogaea root tips, and the chemotactic migration rate and infestation rate were 20.72% and 22.50%, respectively. Differential gene expression and pathway enrichment analyses revealed ubiquinone and other terpenoid-quinone biosynthesis pathway, plant hormone signal transduction pathway, and phenylpropanoid biosynthesis pathway in A. hypogaea roots responded to the infestation of M. incognita. Furthermore, the AhHPT gene, encoding homogentisate phytyltransferase, was considered to be an ideal candidate gene due to its higher expression based on the transcriptome data and quantitative real-time PCR analysis. Conclusion: Therefore, the key gene AhHPT might be involved in the A. hypogaea against M. incognita. These findings lay a foundation for revealing the molecular mechanism of A. hypogaea resistance to M. incognita and also provide a prerequisite for further gene function verification, aiming at RKN-resistant molecular breeding.
