Expression of lima bean terpene synthases in rice enhances recruitment of a beneficial enemy of a major rice pest

Abstract

Volatile terpenoids play a key role in plant defence against herbivory by attracting parasitic wasps. We identified seven terpene synthase genes from lima bean, Phaseolus lunatus L. following treatment with either the elicitor alamethicin or spider mites, Tetranychus cinnabarinus. Four of the genes (Pltps2, Pltps3, Pltps4 and Pltps5) were up-regulated with their derived proteins phylogenetically clustered in the TPS-g subfamily and PlTPS3 positioned at the base of this cluster. Recombinant PlTPS3 was able to convert geranyl diphosphate and farnesyl diphosphate to linalool and (E)-nerolidol, the latter being precursor of the homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT). Recombinant PlTPS4 showed a different substrate specificity and produced linalool and (E)-nerolidol, as well as (E,E)-geranyllinalool from geranylgeranyl diphosphate. Transgenic rice expressing Pltps3 emitted significantly more (S)-linalool and DMNT than wild-type plants, whereas transgenic rice expressing Pltps4 produced (S)-linalool, DMNT and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT). In laboratory bioassays, female Cotesia chilonis, the natural enemy of the striped rice stemborer, Chilo suppressalis, were significantly attracted to the transgenic plants and their volatiles. We further confirmed this with synthetic blends mimicking natural rice volatile composition. Our study demonstrates that the transformation of rice to produce volatile terpenoids has the potential to enhance plant indirect defence through natural enemy recruitment.

Attractiveness of Host Plant Volatile Extracts to the Asian Citrus Psyllid, Diaphorina citri, is Reduced by Terpenoids from the Non-Host Cashew

“…as repellents) against a range of insect pests e.g. aphids, leafhoppers, stinkbugs (Hegde et al 2011; Moraes et al 2009; Oluwafemi et al 2011; Sobhy et al 2017), and in indirect defence via recruitment of natural enemy parasitic wasps (Bruce et al 2008; Li et al 2017; Moraes et al 2009; Tamiru et al 2011). Furthermore, Magalhães et al (2012) suggested that cotton boll weevils, Anthonomus grandis recognize the physiological stage of host cotton plants via information on the amount of DMNT and TMTT released by cotton plants.…”

Identification and functional analysis of two P450 enzymes of Gossypium hirsutum involved in DMNT and TMTT biosynthesis

“…The roles of DMNT and TMTT in attracting parasitoids of herbivores have spurred growing interest in improving natural plant defence via the genetic engineering of DMNT and TMTT formation. C. chilonis were more attracted to rice plants with overexpression of TPS3 and TPS4 genes of P. lunatus, which released more DMNT and TMTT than wild-type rice plants (Li et al, 2017). Transgenic Lotus japonicus plants with the TPS2 gene of P. lunatus produced TMTT, and the specialist P. persimilis was strongly attracted to herbivore-damaged L. japonicas expressing this gene (Brillada et al, 2013).…”

“…Lima bean and thale cress (Arabidopsis thaliana) plants release homoterpenes to attract predatory mites when attacked by spider mites (Lee et al, 2010;Mumm et al, 2008). Rice (Oryza sativa) plants produce homoterpenes highly attractive to females of Cotesia chilonis after attack by the striped rice stem borer Chilo suppressalis (Li et al, 2017). Campoletis sonorensis and Cotesia marginiventris also respond to homoterpenes released by Spodoptera littoralis-infested cotton (Gossypium herbaceum) or maize (Zea mays) plants (Gouinguen e et al, 2005).…”

Removing constraints to sustainable food production: new ways to exploit secondary metabolism from companion planting and GM

“…For industrial agriculture, such highly volatile and chemically unstable compounds cannot be formulated in a cost‐effective manner, so use of GM to generate crops that can more effectively use these semiochemicals is appealing. Already the crop plant rice has been genetically modified to produce increased levels of DMNT and TMTT, and in laboratory studies increased the foraging behaviour of the parasitoid, C. chilonis , Braconidae, attacking the rice pest Chilo suppressalis , Crambidae . This study is a prelude to attempting control of the brown planthopper , Nilaparvata lugens, Delphacidae, the major rice pest.…”

“…Already the crop plant rice has been genetically modified to produce increased levels of DMNT and TMTT, and in laboratory studies increased the foraging behaviour of the parasitoid, C. chilonis, Braconidae, attacking the rice pest Chilo suppressalis, Crambidae. 29 This study is a prelude to attempting control of the brown planthopper, Nilaparvata lugens, Delphacidae, the major rice pest.…”