Abe Hiroshi, Shimoda Takeshi, Ohnishi Jun, Kugimiya Soichi, Narusaka Mari, Seo Shigemi, Narusaka Yoshihiro, Tsuda Shinya, Kobayashi Masatomo
Experimental Plant Division, RIKEN BioResource Center, Tsukuba 305-0074, Japan.
BMC Plant Biol. 2009 Jul 27;9:97. doi: 10.1186/1471-2229-9-97.
The western flower thrips (Frankliniella occidentalis [Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an Arabidopsis leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated Arabidopsis defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (Brassica rapa subsp. pekinensis).
Thrips oviposited more on Arabidopsis JA-insensitive coi1-1 mutants than on WT plants, and the population density of the following thrips generation increased on coi1-1 mutants. Moreover, thrips preferred coi1-1 mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in B. rapa. Thrips feeding induced expression of these marker genes and significantly increased the JA content in B. rapa. Application of JA to B. rapa enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.
Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of Arabidopsis and B. rapa to thrips damage.
西花蓟马（Frankliniella occidentalis [Pergande]）是栽培植物中最重要的食草昆虫之一。然而，没有一种农药能完全控制该物种，且世界各地已出现对杀虫剂的抗性。我们之前利用拟南芥叶盘系统报道了茉莉酸（JA）在植物对蓟马取食的即时反应中的重要作用。在本研究中，作为将JA实际应用于蓟马防治的第一步，我们在全株水平上分析了JA调控的拟南芥防御对蓟马行为和种群水平上的生命周期的影响，研究时间跨度较长。我们还研究了JA调控的植物防御对大白菜（Brassica rapa subsp. pekinensis）蓟马危害的有效性。
蓟马在拟南芥JA不敏感的coi1 - 1突变体上的产卵量比在野生型植物上更多，且下一代蓟马在coi1 - 1突变体上的种群密度增加。此外，蓟马对coi1 - 1突变体的偏好超过野生型植物。在蓟马攻击之前对野生型植物施用JA可减少蓟马种群数量。为了分析JA在十字花科作物中的这些重要功能，我们分析了白菜中JA反应标记基因的表达。蓟马取食诱导了这些标记基因的表达，并显著增加了白菜中的JA含量。对白菜施用JA增强了植物对蓟马的抗性，限制了产卵，并降低了下一代的种群密度。
我们的结果表明，JA调控的植物防御限制了蓟马的表现和偏好，并在拟南芥和白菜对蓟马危害的抗性中发挥重要作用。
