Plant structural traits can act as barriers for herbivore attachment, feeding, and oviposition. In particular, epicuticular waxes (EWs) on the aerial surfaces of many land plants offer protection from biotic and abiotic stresses. In rice (Oryza sativa L.), mutations that reduce EWs have been previously reported. However, whether such mutations affect rice water weevil (Lissorhoptrus oryzophilus Kuschel) and fall armyworm (Spodoptera frugiperda Smith) performance has not been investigated yet. These pests cause significant economic problems in important rice-producing areas of the United States. The aim of our study was to characterize the EWs of EW mutants and wild-type rice plants by gas chromatography–mass spectrometry and compare the resistance of mutant and wild-type plants against rice water weevil and fall armyworm. We hypothesized that mutants with reduced EWs would have weaker resistance to pests than wild-type plants. Three mutant lines (6-1A, 7-17A, and 11-39A) and their wild-type parent (cv. ‘Sabine’) were used to test this hypothesis. Levels of EWs were significantly lower in mutant lines than in the wild-type, and qualitative differences in EW composition were also observed. Reduction in EWs significantly affected performance of insects in experiments conducted under greenhouse conditions. Experiments with rice water weevils were conducted in arenas in which females were given a choice of the mutants and the wild-type for oviposition. Number of first instars emerging from the three EW mutants (an indication of oviposition preference) was higher on the three EW mutants than on wild-type plants with normal wax levels. Similarly, in no-choice experiments using whole plants or detached leaves, weight gains of armyworms on leaves were higher on the mutant lines than on the wild-type. These results indicate that EW traits are involved in rice resistance to weevils and armyworms. Understanding the plant traits that contribute to resistance to rice pests will be helpful for the development of resistant varieties for reducing pest insect damage.

中文翻译：

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表皮蜡米突变体对稻水象甲（鞘翅目：象甲科）和秋粘虫（鳞翅目：夜蛾科）的抵抗力降低


植物结构特征可以作为草食动物附着、进食和产卵的障碍。特别是，许多陆地植物气生表面的表皮蜡（EW）可以提供免受生物和非生物胁迫的保护。在水稻（Oryza sativa L.）中，先前已报道过减少 EW 的突变。然而，此类突变是否影响稻水象甲（Lissorhoptrus oryzophilus Kuschel）和草地贪夜蛾（Spodoptera frugiperda Smith）的性能尚未得到研究。这些害虫给美国重要的稻米产区带来了严重的经济问题。我们研究的目的是通过气相色谱-质谱法表征EW突变体和野生型水稻植物的EW，并比较突变体和野生型植物对稻水象甲和草地贪夜蛾的抗性。我们假设 EW 减少的突变体对害虫的抵抗力比野生型植物更弱。使用三个突变株系（6-1A、7-17A 和 11-39A）及其野生型亲本（cv.“Sabine”）来检验这一假设。突变系中的 EW 水平显着低于野生型，并且还观察到 EW 成分的质量差异。在温室条件下进行的实验中，EW 的减少显着影响了昆虫的表现。稻水象甲的实验是在竞技场中进行的，雌性可以选择突变体和野生型进行产卵。从三个 EW 突变体中出现的第一龄数（表明产卵偏好）在三个 EW 突变体中高于具有正常蜡水平的野生型植物。 类似地，在使用整株植物或分离的叶子的无选择实验中，突变株系叶片上粘虫的重量增加高于野生型。这些结果表明，EW 性状与水稻对象鼻虫和粘虫的抗性有关。了解有助于抵抗水稻害虫的植物性状将有助于开发抗病品种以减少害虫危害。