Chen Gang, Escobar-Bravo Rocío, Kim Hye Kyong, Leiss Kirsten A, Klinkhamer Peter G L
Plant Science and Natural Products, Institute of Biology, Leiden University, Leiden, Netherlands.
Business Unit Horticulture, Wageningen University and Research Center, Bleiswijk, Netherlands.
Front Plant Sci. 2018 Sep 26;9:1417. doi: 10.3389/fpls.2018.01417. eCollection 2018.
Western flower thrips (WFT) (Pergande) is a key agricultural pest of cultivated tomatoes. Induced host plant resistance by activating jasmonic acid (JA) signaling pathway constitutes a promising method for WFT control. The phytotoxin coronatine (COR), produced by pv. tomato DC3000 (), mimics the plant hormone JA-Isoleucine and can promote resistance against herbivorous arthropods. Here we determined the effect of and COR on tomato resistance against WFT, induction of JA and salicylic acid (SA) associated defenses, and plant chemistry. Additionally, we investigated the presence of other components in -derived and filtered culture medium, and their interactive effect with COR on tomato resistance to WFT. Our results showed that infiltration of COR or reduced WFT feeding damage in tomato plants. COR and induced the expression of JA-associated gene and protein marker. COR also induced expression of a SA-related responsive gene, although at much less magnitude. Activation of JA defenses in COR and infiltrated plants did not affect density of type VI leaf trichomes, which are defenses reported to be induced by JA. An untargeted metabolomic analysis showed that both treatments induced strong changes in infiltrated leaves, but leaf responses to COR or slightly differed. Application of the -derived and filtered culture medium, containing COR but not viable , also increased tomato resistance against WFT confirming that the induction of tomato defenses does not require a living population to be present in the plant. Infiltration of tomato plants with low concentrations of COR in diluted -derived and filtered culture medium reduced WFT feeding damage in a greater magnitude than infiltration with an equivalent amount of pure COR indicating that other elicitors are present in the medium. This was confirmed by the fact that the medium from a COR-mutant of also strongly reduced silver damage. In conclusion, our results indicate that induction of JA defenses by COR, infection, the medium of and the medium of a COR mutant increased resistance against WFT. This was not mediated by the reinforcement of leaf trichome densities, but rather the induction of chemical defenses.
西花蓟马（WFT）（Pergande）是栽培番茄的一种关键农业害虫。通过激活茉莉酸（JA）信号通路诱导宿主植物抗性是一种很有前景的防治西花蓟马的方法。由番茄致病变种DC3000（）产生的植物毒素冠菌素（COR），模拟植物激素茉莉酸异亮氨酸，可增强对植食性节肢动物的抗性。在此，我们确定了和COR对番茄抗西花蓟马的影响、与茉莉酸和水杨酸（SA）相关防御的诱导以及植物化学组成。此外，我们研究了源自和过滤后的培养基中其他成分的存在情况，以及它们与COR对番茄抗西花蓟马的交互作用。我们的结果表明，COR或的浸润减少了番茄植株上西花蓟马的取食损伤。COR和诱导了茉莉酸相关基因和蛋白质标记物的表达。COR还诱导了一个与水杨酸相关的响应基因的表达，尽管程度要小得多。在COR和浸润的植株中激活茉莉酸防御并未影响VI型叶毛的密度，而叶毛是据报道由茉莉酸诱导的防御。一项非靶向代谢组学分析表明，两种处理均在浸润叶片中诱导了强烈变化，但叶片对COR或的反应略有不同。应用含有COR但不含活的的源自和过滤后的培养基，也增强了番茄对西花蓟马的抗性，这证实了番茄防御的诱导并不需要植物中存在活的群体。用低浓度COR在稀释的源自和过滤后的培养基中浸润番茄植株，比用等量纯COR浸润更能显著减少西花蓟马的取食损伤，这表明培养基中存在其他激发子。这一点通过以下事实得到证实：来自的COR突变体的培养基也能显著减少银叶损伤。总之，我们的结果表明，COR、感染、的培养基和的COR突变体的培养基诱导茉莉酸防御增强了对西花蓟马的抗性。这不是通过增强叶毛密度介导的，而是通过诱导化学防御实现的。
