Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts, United States of America.
Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
PLoS One. 2021 Jul 30;16(7):e0248202. doi: 10.1371/journal.pone.0248202. eCollection 2021.
Food resource access can mediate establishment success in invasive species, and generalist herbivorous insects are thought to rely on mechanisms of transcriptional plasticity to respond to dietary variation. While asexually reproducing invasives typically have low genetic variation, the twofold reproductive capacity of asexual organisms is a marked advantage for colonization. We studied host-related transcriptional acclimation in parthenogenetic, invasive, and polyphagous weevils: Naupactus cervinus and N. leucoloma. We analyzed patterns of gene expression in three gene categories that can mediate weevil-host plant interactions through identification of suitable host plants, short-term acclimation to host plant defenses, and long-term adaptation to host plant defenses and their pathogens. This approach employed comparative transcriptomic methods to investigate differentially expressed host detection, detoxification, immune defense genes, and pathway-level gene set enrichment. Our results show that weevil gene expression responses can be host plant-specific, and that elements of that response can be maintained in the offspring. Some host plant groups, such as legumes, appear to be more taxing as they elicit a complex gene expression response which is both strong in intensity and specific in identity. However, the weevil response to taxing host plants shares many differentially expressed genes with other stressful situations, such as host plant cultivation conditions and transition to novel host, suggesting that there is an evolutionarily favorable shared gene expression regime for responding to different types of stressful situations. Modulating gene expression in the absence of other avenues for phenotypic adaptation may be an important mechanism of successful colonization for these introduced insects.
食物资源的可获得性可以调节入侵物种的建立成功率，而广义的草食性昆虫被认为依赖于转录可塑性机制来应对饮食变化。虽然无性繁殖的入侵物种通常遗传变异较低，但无性生物的两倍繁殖能力是其殖民化的显著优势。我们研究了孤雌生殖、入侵和多食性象鼻虫（Naupactus cervinus 和 N. leucoloma）的与宿主相关的转录适应性。我们分析了三个基因类别中的基因表达模式，这些基因类别可以通过识别合适的宿主植物、短期适应宿主植物防御以及长期适应宿主植物防御及其病原体来介导象鼻虫与宿主植物的相互作用。这种方法采用比较转录组学方法来研究差异表达的宿主检测、解毒、免疫防御基因和途径水平的基因集富集。我们的结果表明，象鼻虫的基因表达反应可以是宿主植物特异性的，并且这种反应的某些元素可以在后代中保留。一些宿主植物群，如豆类，似乎更具挑战性，因为它们引发了强烈而特异性的复杂基因表达反应。然而，象鼻虫对具有挑战性的宿主植物的反应与其他压力情况（如宿主植物的栽培条件和向新宿主的过渡）共享许多差异表达的基因，这表明存在一种有利于进化的共享基因表达机制，用于应对不同类型的压力情况。在没有其他表型适应途径的情况下调节基因表达可能是这些引入昆虫成功殖民的重要机制。
