Discovery of novel nematicidal active ingredient 2,4,7-trichloroquinazoline as a potential succinic dehydrogenase inhibitor

Abstract

Plant-parasitic nematodes seriously affect the growth and yield of crops, causing huge economic losses to world agriculture. One of the effective ways to manage nematode diseases is the use of nematicides. Compound B1 was found to have good nematicidal activity in the biological test. Therefore, some compounds with similar structures to B1 were tested for better nematicidal activities. Among them, the LC50 of compound C3 against pine wood nematode (Bursaphelenchus xylophilus), rice stem nematode (Aphelenchoides besseyi), and sweet potato stem nematode (Ditylenchus destructor) were 4.6, 22.4, and 16.9 mg/L, respectively, which are markedly better than tioxazafen (103.9, 56.2, and 61.0 mg/L). Compound C3 was capable of not only significantly promoting oxidative stress in Bursaphelenchus xylophilus (B. xylophilus), but also curtailing population growth by influencing the frequency of head swing frequency, feeding behaviors, reproductive capabilities, and egg hatching rates. Furthermore, Compound C3 has demonstrated a favorable binding affinity to the succinic dehydrogenase (SDH) protein and has significantly dampened the activity of the SDH in B. xylophilus. Therefore, compound C3 can be used as a potential lead compound to discover new nematicides.