Plant volatile compounds such as monoterpenes and sesquiterpenes represent some of the classes of plant volatile compounds and they are involved in the plant defense responses. They are synthesized by terpene synthases (TPSs). The rice genome has reportedly more than 30 TPSs genes and several of them are regulated by a plant hormone, jasmonic acid (JA). In the present study, we analyzed a rice terpene synthase, OsTPS21, and investigated its potential antibacterial effects against Xanthomonas oryzae pv. oryzae (Xoo), which causes rice bacterial blight. OsTPS21 was localized in the chloroplast and produced a monoterpene geraniol as a monoterpene synthase. In addition, OsTPS21 did not exhibit any activity as a sesquiterpene synthase. The amount of geraniol in rice increased along with the upregulation of OsTPS21 after JA treatment. Geraniol had a negative effect on the growth of Xoo. The growth inhibition of Xoo by geraniol was caused by the suppression of expression of the cell-division-related genes of Xoo and not by damage to Xoo cell membranes. The results suggest that geraniol plays an important role in JA-induced resistance against Xoo and that it functions as an antibacterial compound in rice.

植物挥发性化合物如单萜和倍半萜代表了一些植物挥发性化合物类别，它们参与植物防御反应。它们由萜烯合酶 (TPS) 合成。据报道，水稻基因组有 30 多个 TPS 基因，其中一些受植物激素茉莉酸 (JA) 调控。在本研究中，我们分析了水稻萜烯合酶 OsTPS21，并研究了其对米黄单胞菌pv 的潜在抗菌作用。米科( Xoo)，这会导致水稻白叶枯病。OsTPS21 位于叶绿体中并产生单萜香叶醇作为单萜合酶。此外，OsTPS21 没有表现出任何作为倍半萜烯合酶的活性。JA处理后水稻中香叶醇的含量随着OsTPS21的上调而增加。香叶醇对Xoo的生长有负面影响。的生长抑制白叶枯病由香叶醇用的细胞分裂相关的基因的表达的抑制导致白叶枯病，而不是由损坏白叶枯病细胞膜。结果表明，香叶醇在 JA 诱导的Xoo抗性中起重要作用 并且它在大米中起到抗菌化合物的作用。