Role of steroid compounds in relationship of plants and parasitic nematodes

Abstract

Literature data on steroid metabolism of plant-parasitic nematodes and own research on the feasibility of regulating the number of pathogenic nematodes using plant steroids are presented. Steroidal compounds are essential components of cell membranes, play a significant role in the regulatory process and are signaling mo- lecules. On one side it was shown possibility to affect the steroid metabolism of nematodes depressing their development, depriving necessary sterols; on other side to impact the mevalonate pathway in plants enhancing their immune properties. Analysis of a number of steroid compounds: glycoalkaloids, saponins and ecdy- sones extracted from plants of the Solanaceae, Labiatae and Dioscoreaceae, shows that all tested compounds to a greater or lesser degree can affect the development of the nematode. In examined tomato plant system Solanum esculentum Mill, root- knot nematode Meloidogyne incognita (Kofoid et White) Chitwood, the highest activity among steroidal glycoalkaloids had ɑ-tomatin and ɑ-chaconine, among saponins - tomatozide. While observing the direct impact of steroids on nematodes, we can point out the nematostatic effect of compounds in applied concentrations. On the example of tomato plants treated with ɑ-tomatin the activity of protease inhibitors, agents interrupting digestion of insects and nematodes, is analyzed. Treatment of plants with ɑ-tomatin increases the activity of trypsin inhibitors in the tomato tissues that allows expecting the relation between the plant treatment with ɑ-tomatin and degree of resistance of tomato to nematodes

Keywords

• plant-parasitic nematodes
• rootknot nematodes
• steroids