美洲棉铃虫幼虫腹侧可外翻腺分泌物对番茄抗虫反应的影响

为明确美洲棉铃虫Helicoverpa zea幼虫腹侧可外翻腺(ventral eversible gland,VEG)分泌物对植物抗虫反应的影响,在宾夕法尼亚州立大学帕克分校校园日光温室大棚内分别测定取食未损伤、机械损伤后涂抹磷酸缓冲盐溶液(phosphate buffer saline,PBS)和机械损伤后涂抹VEG分泌物3种处理的番茄叶片后美洲棉铃虫幼虫体重增加量,不同处理番茄叶片中防御关键酶多酚氧化酶(polyphenol oxidase,PPO)活性、胰蛋白酶抑制剂(trypsin proteinase inhibitors,TPI)抑制率以及防御相关的蛋白酶抑制剂Ⅱ(proteinase inhibitor Ⅱ,PIN2)基因相对表达量。结果显示,3种处理中,取食机械损伤后涂抹VEG分泌物的番茄叶片的美洲棉铃虫幼虫体重较处理前增加量最少,为4.27 mg,显著低于其它2种处理;机械损伤后涂抹VEG分泌物的番茄叶片中PPO活性和TPI抑制率最高,分别为109.16 U/mg和27.48%,分别显著高于其它2种处理;同时机械损伤后涂抹VEG分泌物的番茄叶片中PIN2基因相对表达量显著上调,分别是未损伤和机械损伤后涂抹PBS缓冲液处理的11.83倍和1.17倍。表明美洲棉铃虫幼虫VEG分泌物能够促使防御关键酶的大量积累,使得防御相关基因的相对表达量上调,显著诱导番茄的抗虫反应,阻止后续昆虫的取食。

Effects of ventral eversible gland secretions of American cotton bollworm Helicoverpa zea caterpillars on anti-herbivore responses in tomato

To explore the effect of secretions from the ventral eversible gland (VEG) of American cotton bollworm Helicoverpa zea caterpillars on plant anti-herbivore responses, tomato plants were used as the experimental materials and three plant damage treatments were set to compare the differences of caterpillar weight gain, defensive key enzymes of polyphenol oxidase (PPO), inhibition rate of trypsin proteinase inhibitors (TPI) and relative gene (proteinase inhibitor II, PIN2) expressions in tomato leaflets including undamaged, mechanical wounding with application of phosphate buffer saline (PBS) and mechanical wounding with application of VEG secretions in the greenhouse of Pennsylvania State University, University Park. The results showed that the application of VEG secretions significantly decreased caterpillar weight gain with 4.27 mg, which was significantly lower than caterpillars that fed on leaflets which were undamaged and mechanical wounding with application of PBS, respectively; the application of VEG secretions significantly increased the accumulation of PPO with 109.16 U/mg and inhibition rate of TPI with 27.48% and up-regulated the expression of PIN2 in tomato leaflets; which were 11.83 or 1.17 times higher than that in tomato leaflets undamaged or mechanically wounded with application of PBS. Taken together, VEG secretions of H. zea caterpillars were capable to accumulate plant defense related key enzymes, up-regulate plant defense related genes, significantly trigger plant anti-herbivore defenses and retard the subsequent caterpillars.