Nematicidal activity of pyrazine compounds against Meloidogyne incongnita, Burshaphelenchus xylophilus, and Aphelenchoides besseyi.

The increase of plant parasitic nematode resistance poses a great threat to agricultural and forestry production. To search for nematicides with novel mechanism of action, nematicidal activity of the 29 pyrazine compounds were tested. Compound C2 showed excellent nematicidal activity against Bursaphelenchus xylophilus, Meloidogyne incongnita, and Aphelenchoides besseyi, with LC50 values were 2.3, 3.3, and 10.6 mg/L, respectively, and the pot experiment showed that C2 reduced the number of tomato roots knots to a certain extent. In addition, C2 significantly inhibited egg hatching, locomotion and reproductive ability of B. xylophilus, and also reduced the levels of protein and antioxidant enzyme activity to some extent, and the indexes related to oxidative stress showed an increasing trend after treatment. The novel chemical structure of compound D was designed and synthesized based on the lead compound C2 by the scaffold hopping strategy. Interestingly, compound D also has excellent nematicidal activity. Compound D can be used as an excellent scaffold in the discovery of novel nematicides and we will continue to work on the optimization and modification of this scaffold structure in the future.