烟粉虱取食对不同抗虫性辣椒品种营养物质和抗性物质的影响

Effects of Bemisia tabaci feeding on nutrients and resistance-related compounds of pepper varieties with different insect resistances

为了探讨烟粉虱取食对辣椒体内营养物质和抗性物质的影响,选择抗虫辣椒品种(‘新一代三鹰椒’、‘新苏椒五号’)和感虫品种(‘苏椒13号’、‘苏椒15号’)各2个,每株辣椒分别接烟粉虱成虫0头(对照)、30头(低密度)、60头(中密度)和120头(高密度),取食24 h后测定辣椒叶片中叶绿素、可溶性糖、可溶性蛋白以及酚类、黄酮类化合物含量。结果发现,低密度的烟粉虱取食后,辣椒叶片叶绿素含量显著上升,随着虫口密度的提高,叶绿素含量有所下降,但仍高于对照;感虫辣椒品种的叶绿素含量增加幅度高于抗虫品种。低密度和高密度的烟粉虱取食后,辣椒叶片中可溶性糖含量出现明显下降趋势,抗虫品种的下降幅度大于感虫品种。低密度和中密度的烟粉虱取食后,辣椒叶片中可溶性蛋白含量显著下降,但高密度烟粉虱取食后辣椒叶片中可溶性蛋白含量明显上升;抗虫品种的变化幅度明显高于感虫品种。烟粉虱取食后,叶片中酚类化合物含量明显上升,感虫品种的上升幅度较抗虫品种上升幅度大;随着虫量的增加,辣椒叶片中酚类化合物含量呈明显上升趋势,但高密度烟粉虱取食后酚类化合物含量出现明显下降趋势。烟粉虱取食后,感虫辣椒品种‘苏椒15号’叶片中黄酮类化合物含量明显上升;其他3个品种在中等以下密度的烟粉虱取食时,黄酮类化合物与对照差异不显著,但在高密度烟粉虱取食时,黄酮类化合物明显高于对照。研究表明,烟粉虱取食可引起辣椒营养物质和抗性物质含量向着有利于提高抗虫性的方向改变,但不同虫口密度下不同辣椒品种的改变幅度不同。研究结果为进一步揭示寄主植物与烟粉虱之间的防御和反防御机制提供了基础。

Induced insect resistance is a series of defending reactions of plant under biotic and abiotic stress.In order toexplore the effects of Bemisia tabaci feeding on induced insect resistance of different varieties of pepper,and illuminate theinsect resistance mechanisms,we conducted an experiment in insectary.In the experiment,two insect-resistant varieties(‘Xinyidai Sanying’and‘Xinsujiao5’)and two insect-susceptible varieties(‘Sujiao13’and‘Sujiao15’)of pepper wereselected and infected with B.tabaci adults0(control),30(lower density),60(middle density)and120(higher density)heads per plant,respectively.The contents of chlorophyll,soluble sugar,soluble protein,phenol compound and flavonoidsin pepper leaves were determined after24h of feeding of B.tabaci.The results showed that leaf chlorophyll content ofpepper under feeding of lower density of B.tabaci was significantly increased,and the chlorophyll content decreased withthe increase of population density of the insect,but was still higher than that of the control.The increase of chlorophyllcontent in the insect-susceptible pepper varieties was higher than that of the insect-resistant varieties.The content of solublesugar in pepper leaves showed a decreasing trend after infected with the insects with lower and higher densities,and thedecreased level of insect-resistant varieties was higher than that of insect-susceptible varieties.The content of soluble proteinin pepper leaves decreased after infected by the insects with lower and middle densities,but increased when fed by highdensity insects.The changing range of soluble protein contents of insect-resistant pepper varieties was higher than that ofinsect-susceptible varieties.The contents of phonemic compounds in leaves increased significantly after B.tabaci feeding,and the increase rate of insect-susceptible varieties was higher than that of the insect-resistant cultivars.With the increasedinsect density,the content of phenolic compounds in pepper leaves showed a significant upward trend,but decreased obviouslywhen the population density was120head per plant.We also found that the content of flavonoids in the leaves ofpepper‘Sujiao15’was significantly increased after B.tabaci feeding,and that in other varieties under middle insect densitywere not significantly different from that of the control.However,in the case of higher insect density,the content of flavonoidswas significantly higher than that of control.Our results indicated that the feeding of B.tabaci changed contents ofnutrients and resistant substances in the direction of improving insect resistance.The extents of change of different pepper varieties under different insect densities were different.The results provided a basis for further revealing the defense andanti-defense mechanisms between hos plant and B.tabaci.