南美斑潜蝇为害对黄瓜叶片中蛋白酶抑制剂活性及葫芦素B含量的影响

【目的】蛋白酶抑制剂和葫芦素是两类在植物中具有抗虫活性的化合物,在植食性昆虫与其寄主植物相互作用中起着重要的作用。本文在室内研究了南美斑潜蝇Liriomyza huidobrensis(Blanchard)为害对黄瓜叶片中蛋白酶抑制剂活性及葫芦素B含量的影响,以期揭示南美斑潜蝇与其寄主植物相互作用的机理以及为利用诱导抗性控制南美斑潜蝇的为害奠定必要的基础。【方法】用分光光度法和高效液相色谱法,分别测定了南美斑潜蝇幼虫为害后黄瓜叶片中蛋白酶抑制剂活性和葫芦素B含量的变化。【结果】在南美斑潜蝇幼虫为害期间(1~9 d),黄瓜叶片中胰蛋白酶抑制剂和胰凝乳蛋白酶抑制剂活性及葫芦素B含量与健康对照相比显著上升,但上升幅度并不与为害强度和为害持续时间相一致,其中对胰蛋白酶抑制剂具有系统诱导作用,而对胰凝乳蛋白酶抑制剂和葫芦素B的系统诱导作用不明显。【结论】南美斑潜蝇幼虫为害可诱导寄主植物体内蛋白酶抑制剂活性和葫芦素B含量上升,培育蛋白酶抑制剂或葫芦素含量高或易诱导的黄瓜品种可能是控制南美斑潜蝇为害的有效途径。

Effects of Liriomyza huidobrensis （Blanchard） larval infestation on trypsin and chymotrypsin activity and cucurbitacin B content in cucumber leaves

Objectives] Protease inhibitors and cucurbitacins are two kinds of insect-resistant compounds in plants that are important in the interactions between herbivorous insects and their host plants. We studied the effects of Liriomyza huidobrensis （Blanchard） larval infestation on the activities of protease inhibitors and cucurbitacin B content in cucumber leaves in order to investigate the mechanisms of interaction between the leaf miner and its host plants, and to build a necessary foundation for use of inducible resistance to control the leaf miner. Methods] Spectrophotometry was used to determine the changes of the activities of protease inhibitors and High-Performance Liquid Chromatography （HPLC） to determine the cucurbitacin B content in cucumber leaves. Results] The activities of trypsin and chymotrypsin inhibitors, and the cucurbitacin B content in cucumber leaves increased during larval infestation （1-9 d）, compared to control plants, but the magnitudes of these increases were not consistent with the infestation levels and durations. Induction of the trypsin inhibitor was systemic while induction of the chymotrypsin inhibitor and cucurbitacin B were not. Conclusion] Larval infestation can induce an increase in protease inhibitor activity and cucurbitacin B, and the breeding of cucumber varieties with inducible protease inhibitor and/or cucurbitacin B may be an effective approach for controlling the leaf miner.