玉米蚜虫取食诱导型启动子的筛选及用于调控报警信息素EβF合成的研究

(E)-β-farnesene (EβF) is the main or even the only alarm pheromone involved in the chemical communication within aphid species. It could cause repulsion of aphids and also attraction of natural enemies that use EβF as a foraging cue, thus minimizing aphid infestation. Previous studies have shown that overexpression of EβF in some plants resulted in decreased aphid infestation, but constitutive emission of EβF from some plant species had no effect on plant defense against aphids. In this study, maize infested by aphids will be used for transcriptome analysis to identify the aphid-inducible promoters, and the EβF synthase gene (MaβFS) from Asian peppermint driven by a constitutive cauliflower mosaic virus 35S promoter and the selected aphid inducible promoters will be transformed into the maize inbred line A188, respectively. The levels of EβF synthase expression and volatiles emitted from the transgenic lines will be evaluated by qRT-PCR and GC-MS. According to the results of qRT-PCR and GC-MS, transgenic lines with higher EβF emissions will be selected for aphid repelling and predator attraction bioassays in comparison with the wild-type maize. This work will provide important information about aphid-inducible promoters, which could be used in pest management, and is important for the application of EβF for aphid control, and it is also valuable for creating new aphid-resistant maize germplasm.

[反]-β-法尼烯（EβF）作为大多数蚜虫报警信息素的主要甚至唯一成份，不但可以使蚜虫产生骚动、从植株上脱落，还可以吸引蚜虫天敌，进而可以有效地保护植物免受蚜虫危害。研究表明，通过组成型启动子调控EβF合成酶基因表达虽然在某些植物中可以降低蚜虫的危害，然而持续释放EβF的某些植物对蚜虫却并没有驱避性。因此，本研究以玉米自交系A188为材料，以玉米蚜为研究对象，通过分析蚜虫诱导的玉米转录组数据，挑选蚜虫特异诱导基因的启动子，进而应用农杆菌介导的植物转化技术，获得由不同类型启动子调控亚洲薄荷EβF合成酶基因（MaβFS）表达的转基因玉米植株。利用qRT-PCR、GC-MS等分析MaβFS基因表达和挥发物释放，再结合生物测定分析确定最佳调控EβF合成的诱导型启动子。本研究将为发掘和利用蚜虫特异启动子用于生物防治提供重要信息，并为有效利用EβF控制蚜虫提供理论依据，对创制新型抗蚜虫玉米有指导价值。

蚜虫是重要的农业害虫，通过吸食作物汁液或传播病毒病而导致作物严重减产。[反]-β-法尼烯（EβF）作为大多数蚜虫报警信息素的主要甚至唯一成份，不但可以使蚜虫产生骚动、从植株上脱落，还可以吸引蚜虫天敌，进而可以有效地保护植物免受蚜虫危害。在本研究中，我们首先将来自于亚洲薄荷的EβF基因（I型）以及经过玉米密码子优化过的亚洲薄荷基因（II型）进行了合成，随后我们又在II型EβF基因中加入了一小段内含子获得III型EβF。通过农杆菌介导法将I，II，III型EβF基因分别过表达到玉米自交系A188中，我们发现这三种转基因玉米品种对玉米蚜虫均能表现出一定的驱蚜和吸引蚜虫天敌效果，其中转III型EβF基因玉米效果最好。之后，我们又进一步获得了蚜虫诱导型启动子特异调控转III型EβF基因的玉米品系，选择部分T0代株系进行检测，结果显示III型EβF基因已经整合到玉米基因组中，目前正在检测转III型EβF基因玉米株系能否只有在受到蚜虫取食后才释放EβF以趋避蚜虫并吸引蚜虫天敌，进而起到保护自身的作用。