Integrated analysis of mineral ion dynamics in rice crop exposed to acute herbivory stress

我们一直在关注硅（Si）、镍（Ni）和重金属镉（Cd）以及氨基酸运输在昆虫摄食反应中的作用。(1)采用含硅和不含硅的水培体系研究了硅的作用。咀嚼食草动物Mythimna loreyi的幼虫在无硅水稻上表现明显更好，证实了先前的报道。我们进一步确定了硅供应足以恢复水稻抗草食动物抗性的最短时间。我们还研究了硅在水稻挥发性信号释放中的作用以及硅对水稻基因表达的影响。(2)草食动物可以促进镍的吸收。因此，研究了镍在防御中的新作用。特别是，镍作为脲酶的辅助因子在氮代谢中的作用可能存在联系。昆虫取食刺激了水稻尿素转运蛋白的表达，进一步支持了这一观点。(3)此外，我们还观察到，在咀嚼和吸吮食草动物攻击后，水稻会瞬间诱导Cd吸收，从而研究了Cd在植物直接防御中的作用。(4)构建了一种高诱导性氨基酸转运体的CRISPR/Cas9基因敲除系（T0代）。(5)含氮代谢物在植物防御中的作用由Aboshi博士进行。(6) Mitani博士进一步阐明了Si转运体在水稻中的作用，特别是SIET蛋白的作用。

We have been focusing on the role of silicon (Si), nickel (Ni) and heavy metal cadmium (Cd), and amino acid transport, in response to insect feeding. (1) The role of Si was investigated using hydroponic culture system supplied with Si and without Si. Larvae of chewing herbivore Mythimna loreyi performed significantly better on Si-free rice that confirmed previous reports. We further determined the minimum time for Si supply that was sufficient to restore anti-herbivore resistance in rice. We also investigated the role of Si in release of volatile signals from rice and effect of Si on gene expression in rice. (2) We found that Ni uptake can be stimulated by herbivore feeding. Therefore, a possibly new role of Ni in defense was investigated. In particular, a possible connection between function of Ni as a cofactor of urease enzyme in nitrogen metabolism was proposed. This was further supported by finding that the expression of urea transporter in rice is stimulated by insect herbivory. (3) Additionally, we investigated the role of Cd in direct plant defense based on the observation that Cd uptake was transiently induced in rice after attack of chewing and sucking herbivores. (4) T0 generation of CRISPR/Cas9 knock-out line of a highly inducible amino acid transporter by herbivory was constructed. (5) The role of nitrogen containing metabolites in plant defense was carried out by Dr. Aboshi. (6) The role of Si transporters in rice has been further clarified by Dr. Mitani, in particular the role of SIET proteins.