| 研究実績の概要 |
In FY25, we established system for measurement of volatiles released from rice and Sorghum plants. In FY26, we further optimized collection method and identification of GC-MS peaks. Analysis of differentially released volatiles was conducted with rice herbivores: (1) generalist Mythimna loreyi, (2) specialist Parnara guttata, and (3) sucking insect brown planthopper, Nilaparvata lugens. Each herbivore elicited different amounts of volatiles and these emissions were dependent on jasmonate signaling. Green leaf volatiles, aromatics and terpenoid emissions changed during day and night photoperiod, and most of these emissions were simply enhanced by herbivory. As planned, the effect of chemical inducers on volatiles from rice and Sorghum was examined. Chemical elicitor thiadiazole-7-carbothioic acid S-methyl ester (BTH) reduced levels of emitted monoterpene linalool, which could be important for recognition of plants by natural enemies, or by ovipositing moths, or by sucking insects. We tested two closely related varieties of Sorghum (NOG, BTX) and found significant differences in their volatile emissions. We now evaluate molecular basis of these differences by analyzing plant hormone signaling. In collaboration, we plan to use hybrid lines (BTX x NOG) developed in the institute for future identification of major QTLs responsible for differential emissions of volatiles. We will examine if differential volatiles may affect field performance and/or defense of Sorghum against insects.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
We substantially advanced in understanding of the basic mechanisms of volatile emissions from monocots plants at the levels of spectrum of emitted volatile compound, timing during the day, and dependence of emissions on plant signaling and genotype. As originally proposed, we also demonstrated the effect of chemical elicitor BTH on volatile emissions from rice and Sorghum plants. We are now ready to proceed into the final stage of the project.
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| 今後の研究の推進方策 |
In the final stage of the project, we focus on characterization of tritrophic plant-herbivore interactions to correlate them with major the differences in volatile emissions found in this project. Based on our intermediate results, major variable parameters in the study will be plant species (rice x Sorghum), Sorghum genotypes (NOG x BTX), herbivore type (1-3 described above) and elicitation status (+/- BTH). We also expect to collect parasitoids specific to P. guttata and M. loreyi larvae from the field and use them in bioassays using Y-tube olfactometer (in FY26, we regularly observed parasitoid infestations in P. guttata larvae collected from the experimental field). We will also examine direct defense capacities of these plants using feeding bioassays. Finally, we will correlate volatile emissions with publicly available gene expression data for genes encoding enzymes in volatile pathways. We prepare and submit manuscripts reklated to work in this project.
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