The rice terpene synthase gene OsTPS19 functions as an (S)‐limonene synthase in planta, and its overexpression leads to enhanced resistance to the blast fungus Magnaporthe oryzae

Abstract

SummaryRice blast disease, caused by the fungus Magnaporthe oryzae, is the most devastating disease of rice. In our ongoing characterization of the defence mechanisms of rice plants against M. oryzae, a terpene synthase gene OsTPS19 was identified as a candidate defence gene. Here, we report the functional characterization of OsTPS19, which is up‐regulated by M. oryzae infection. Overexpression of OsTPS19 in rice plants enhanced resistance against M. oryzae, while OsTPS19 RNAi lines were more susceptible to the pathogen. Metabolic analysis revealed that the production of a monoterpene (S)‐limonene was increased and decreased in OsTPS19 overexpression and RNAi lines, respectively, suggesting that OsTPS19 functions as a limonene synthase in planta. This notion was further supported by in vitro enzyme assays with recombinant OsTPS19, in which OsTPS19 had both sesquiterpene activity and monoterpene synthase activity, with limonene as a major product. Furthermore, in a subcellular localization experiment, OsTPS19 was localized in plastids. OsTPS19 has a highly homologous paralog, OsTPS20, which likely resulted from a recent gene duplication event. We found that the variation in OsTPS19 and OsTPS20 enzyme activities was determined by a single amino acid in the active site cavity. The expression of OsTPS20 was not affected by M. oryzae infection. This indicates functional divergence of OsTPS19 and OsTPS20. Lastly, (S)‐limonene inhibited the germination of M. oryzae spores in vitro. OsTPS19 was determined to function as an (S)‐limonene synthase in rice and plays a role in defence against M. oryzae, at least partly, by inhibiting spore germination.

Construction of High-Density Genetic Map and Identification of QTLs Associated with Seed Vigor after Exposure to Artificial Aging Conditions in Sweet Corn Using SLAF-seq

“…Their promoters bind directly to the bHLH transcription factor MYC2, which is a central regulator of the JA signaling pathway in developmental and stress responses [54][55][56]. In addition, the overexpression of TPS11 in maize, and the terpene synthase gene OsTPS19 in rice, could enhance resistance to fungal pathogens [57,58]. Thus, these three genes may be related to seed vigor after aging.…”

Genetic control of α‐farnesene production in apple fruit and its role in fungal pathogenesis

“…Overexpression of an ( E )‐β‐caryophyllene synthase in transgenic corn roots attracted nematodes that protected the plant from beetles (Degenhardt et al ., ). The importance of terpenes in plant–pathogen interactions has been demonstrated in rice, where overexpression of a ( S ) ‐ limonene synthase ( OsTPS19 ) increased resistance against Magnaporthe oryzae , whilst OsTPS19 RNA interference (RNAi) lines were more susceptible to this fungal pathogen (Chen et al ., ). Few studies have been conducted in fruit.…”

Physiological and molecular analysis of OsTPS30 by gamma irradiation

“…OsTPS18 has localized in the cytoplasm and synthesized sesquiterpenes (E)nerolidol and (E)-β-farnesene (Kiryu et al 2018). OsTPS19 acts as an (S)-lemonine synthetase in rice and defends against Magnaporthe oryzae by inhibiting spore germination (Chen et al 2018). OsTPS20 plays a major role in producing terpene volatiles during abiotic stress (Lee et al 2015).…”