Selenium mediated host plant–mite conflict: defense and adaptation

Abstract

Selenium has shown effectiveness in protecting plants from herbivores. However, some insects have evolved adaptability to selenium. Selenium accumulation in host plants protected them against spider mite feeding. Selenium showed toxic effects on spider mites by reducing growth and interfering with reproduction. After 40 generations on selenium-rich plants, a Tetranychus cinnabarinus strain (Tc-Se) developed adaptability to selenium, with an increased rate of population growth and enhanced ability for selenium metabolism. The high expression of two genes (GSTd07 and SPS1) in the selenium metabolism pathway might be involved in selenium metabolism in spider mites. After GSTd07 and SPS1 were silenced, the selenium adaptability decreased. Recombinant GSTd07 protein promoted the reaction between sodium selenite and glutathione (GSH) and increased the production of sodium selenite metabolites. The results indicated that GSTd07 was involved in the first step of selenium metabolism. Plants can resist spider mite feeding by accumulating selenium. Spider mites subjected to long-term selenium exposure can adapt to selenium by increasing the expression of key genes involved in selenium metabolism. These results elucidate the mechanism of the interaction between mites and host plants mediated by selenium. This study of the interaction between selenium-mediated host plants and spider mites may lead to the development of new and less toxic methods for the prevention and control of spider mites.