Salivary glucose oxidase (GOX) is one of the most abundant salivary proteins in generalist caterpillar Helicoverpa zea. GOX has been hypothesized to benefit H. zea by modulating direct defense responses of plants. Although the function of this protein has been studied, its role remains unclear. The study aims to test the hypothesis that GOX induces similar defensive responses among Solanaceous plants, and has similar consequences for larval performance of H. zea. Using six different plants in Solanaceae, including tomato (Solanum lycopersicum cv. Better Boy and S. lycopersicum var. cerasiforme), bell pepper (Capsicum annuum cv. Revolution), habanero pepper (Capsicum chinense), tomatillo (Physalis philadelphica cv. Tamayo), and tobacco (N. benthamiana), we tested the impact of GOX on induction of two common defense proteins, trypsin protease inhibitors (TPI) and polyphenol oxidases (PPO), and on relative growth rate of H. zea larvae. We found that GOX specifically induced TPI activity in tomato and habanero pepper, and the level of defense protein depended on leaf location. In addition, prior application of GOX did not increase the performance of H. zea in any plant tested. Changes in performance in tomato and habanero pepper matched the induction of TPI. In summary, our findings indicate that GOX induces similar defense responses in some Solanacean plants, but largely depends on species/genotype of plant, and that the presence of GOX did not benefit larval H. zea by modulating direct defense responses of plants. Other mechanisms must be involved in driving the evolution of this salivary protein.

中文翻译：

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棉铃虫唾液葡萄糖氧化酶在茄科中防御蛋白的诱导及其对幼虫性能的影响

唾液葡萄糖氧化酶（GOX）是通才毛毛虫Helicoverpa zea中最丰富的唾液蛋白之一。假设GOX通过调节植物的直接防御反应而有益于玉米。尽管已经研究了这种蛋白质的功能，但其作用仍不清楚。这项研究旨在测试GOX诱导茄科植物中类似的防御反应，并有幼虫表现类似后果的假设美洲棉铃虫。茄科使用六种不同的植物，包括番茄（番茄品种，更好的男孩和番茄变种cerasiforme），甜椒（辣椒品种。革命），哈瓦那辣椒（辣椒（Capsicum chinense），番茄（Physalis philadelphica cv。Tamayo）和烟草（N. benthamiana），我们测试了GOX对两种常见防御蛋白，胰蛋白酶蛋白酶抑制剂（TPI）和多酚氧化酶（PPO）的诱导作用以及对玉米。幼虫的相对生长速率。我们发现GOX在番茄和哈瓦那辣椒中特异性诱导TPI活性，而防御蛋白的水平取决于叶片的位置。此外，GOX的先前应用并没有提高玉米的性能。在任何经过​​测试的工厂中。番茄和哈瓦那辣椒的性能变化与TPI的诱导相匹配。总而言之，我们的发现表明，GOX在一些茄科植物中诱导相似的防御反应，但在很大程度上取决于植物的物种/基因型，并且GOX的存在并不能通过调节植物的直接防御反应而使幼虫玉米粉受益。其他机制也必须参与驱动唾液蛋白的进化。