Activity: Participating in or organising an event › Public lecture/debate/seminar/presentation › Industry
Using silicon to manipulate plant defence, chemical and molecular ecology
There is mounting awareness of the positive effects of plant-available silicon on plant defences against biotic threats. Most of this work has focused on plant pathology while work on arthropod pests has been largely confined to constitutive (‘always-on’) defence and mechanisms that operate directly on pests. This paper will present result from very recent work on the effects of silicon on indirect, induced plant defence that operates via herbivore-attacked plants releasing volatiles to attract natural enemies to serve as ‘bodyguards’. Work in rice demonstrated for two herbivore-parasitoid systems that the identity and ratios of volatiles produced by rice plants is altered soon after herbivore damage commences and that parasitoids are more attracted to the blend from infested plants than undamaged plants. Moreover, damaged plants with prior silicon treatment produce an odour blend that was more attractive than that from damaged plants grown under silicon deficient conditions. Consistent findings were evident in studies with radish and cucumber together with their herbivores and parasitoids. In cucumber, a time series study revealed that silicon treatment led infested plants to be more attractive to parasitoids than were uninfested plants after just one hour of herbivory. For silicon deficient plants, parasitoids did not discriminate between infested and uninfested plants until herbiory had extended for three hours. Transcriptomics showed that silicon affected the expression of genes linked with the jasmonic acid (but not the salicylic acid) pathway as well as the synthesis of volatiles, terpene synthase, lipoxygenase and indole synthesis.