| 研究実績の概要 |
In FY 27, we continued measuring volatile organic compound (VOC) emissions from rice (Oryza sativa) and sorghum (Sorghum bicolor). In both plants, we determined whole spectrum of VOCs dominated by terpenoids, aromatic compounds and green leaf volatiles. In both monocot species, the VOCs were quite similar, dominated by sesquiterpenes and monoterpens. Herbivore feeding and diurnal conditions were main factors influencing VOC emissions, which was further affected by chemical inducers (BTH) and plant genotype. In order to understand the molecular basis of differential emissions of VOCs from monocot plants, both under control and stress conditions (herbivory, wounding), we initiated cloning and investigated gene expression of those genes directly involved in VOC biosynthesis. In order to correlate differential VOCs with plant indirect defense against insects, we also monitored sorghum plants of different genetic backgrounds (resulting in differential VOCs), and investigated their herbivore damage under field conditions. Although direct relationship still needs to be established, sorghum plants of BTx602 origin, which had higher emissions of VOCs, had lower damage from European stem borer (Ostrinia nubilalis) in the field, compared to susceptible NOG genotype (high damage vs. low VOCs). We could propose hypothesis that high VOCs in BTx602 may help these plants to recruit a higher number of natural enemies of O. nubilalis, and thus reduce the successful establishment of this notorious pest on these plants. Several publications summarizing our results are now under preparation.
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