Extracts from Tissue Cultures of Crotalaria spp. as Potential Natural Alternative for Controlling Root-Knot Nematodes

Plants of the genus Crotalaria are known for their antagonistic effect against nematodes. It has been found that pyrrolizidine alkaloids are the main metabolites involved in such antagonistic activity. Aiming at obtaining extracts with higher alkaloid content and enhanced potential for use as bionematicides, we investigated the chemical composition and nematicidal activity of extracts obtained from Crotalaria juncea and Crotalaria ochroleuca cultivated in vitro through micropropagation. Remarkably, extracts from the callus of C. ochroleuca (lethal concentration of 95% (LC95) = 157.7 μg mL-1) and C. juncea (LC95 = 189.9 μg mL-1) exhibited high toxicity against Meloidogyne javanica. The ultra performance liquid chromatography coupled to quadrupole time-of-flight with high mass spectrometry (UPLC-QTOF-MSE) analysis revealed the presence of pyrrolizidine alkaloids, flavones, flavone glycosides, and isoflavones. These findings highlight the potential of tissue culture to obtain extracts from Crotalaria species compared to conventionally cultivated plants and provide a higher concentration of metabolites with nematicidal effects, paving the way for sustainable agriculture.