Host plant defenses of black (Solanum nigrum L.) and red nightshade (Solanum villosum Mill.) against specialist Solanaceae herbivore Leptinotarsa decemlineata (Say)
Citation
Ben-Abdallah, S., Cáceres, L.A., Wang, Z., Renaud, B.J., Lachâal, M., Karray-Bouraoui, N., Hannoufa, A., Scott, I.M. (2019). Host plant defenses of black (Solanum nigrum L.) and red nightshade (Solanum villosum Mill.) against specialist Solanaceae herbivore Leptinotarsa decemlineata (Say). Archives of Insect Biochemistry and Physiology, [online] 101(2), http://dx.doi.org/10.1002/arch.21550
Plain language summary
This study investigated the interactions between plants and insects, specifically two plants in the same family as potato, and a major pest insect of potato, the Colorado potato beetle. Of particular interest was host plant chemistry that differed between the plants and the response by the insect. It was determined that both plants contained chemicals that interfered with feeding while others were toxic when fed to the insects. The findings indicate that these plants could be a source of valuable chemicals that could applied as biopesticides against the Colorado potato beetle.
Abstract
Black nightshade (Solanum nigrum, S. nigrum L.) and red nightshade (Solanum villosum, S. villosum Mill.) are medicinal plants from the Solanaceae family that synthesize glycoalkaloids and other secondary metabolites. To recognize the potential insecticide activity of these compounds, leaf extracts (containing glycoalkaloid and methanol fractions) were tested for enzyme inhibition, antifeedant activity and toxicity. For in-vitro glutathione S-transferase (GST) inhibition activity, we used insecticide-resistant Colorado potato beetle, Leptinotarsa decemlineata (L. decemlineata; Say) midgut and fat-body homogenate. In-vivo toxicity and the antifeedant activity were performed using larval bioassays. The methanol extracts had greater GST inhibitory activity compared to the glycoalkaloids, as well as greater 2nd instar larvae mortality and antifeedant activity. Furthermore, the green leaf volatile compound, cis-hex-3-enyl acetate, at the concentration of 5 ppm, caused 50% mortality of 2nd instar larvae. Our findings suggest the potential usefulness of S. nigrum and S. villosum extracts to control L. decemlineata.