Chen Lei, Guo Li-Xue, Yu Xin-Yue, Huo Shi-Mei, Hoffmann Ary A, Zhou Jia-Yi, Sun Jing-Tao, Hong Xiao-Yue
Department of Entomology, Nanjing Agricultural University, Nanjing, Jiangsu, China.
School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia.
Mol Ecol. 2024 Aug 29:e17521. doi: 10.1111/mec.17521.
The diet breadth of generalist herbivores when compared to specialists tends to be associated with greater transcriptional plasticity. Here, we consider whether it may also contribute to variation in host range among two generalists with different levels of polyphagy. We examined two related polyphagous spider mites with different host ranges, Tetranychus urticae (1200 plants) and Tetranychus truncatus (90 plants). Data from multiple populations of both species domesticated on common beans and transferred to new plant hosts (cotton, cucumber, eggplant) were used to investigate transcriptional plasticity relative to population-based variation in gene expression. Compared to T. truncatus, T. urticae exhibited much higher transcriptional plasticity. Populations of this species also showed much more variable expression regulation in response to a plant host, particularly for genes related to detoxification, transport, and transcriptional factors. In response to the different plant hosts, both polyphagous species showed enriched processes of drug/xenobiotics metabolism, with T. urticae orchestrating a relatively broader array of biological pathways. Through co-expression network analysis, we identified gene modules associated with host plant response, revealing shared hub genes primarily involved in detoxification metabolism when both mites fed on the same plants. After silencing a shared hub CYP gene related to eggplant exposure, the performance of both species on the original bean host improved, but the fecundity of T. truncatus decreased when feeding on eggplant. The extensive transcriptomic variation shown by T. urticae might serve as a potential compensatory mechanism for a deficiency of hub genes in this species. This research points to nuanced differences in transcriptomic variability between generalist herbivores.
与专食性食草动物相比，广食性食草动物的饮食广度往往与更大的转录可塑性相关。在此，我们探讨它是否也可能导致两种具有不同多食性水平的广食性动物在宿主范围上的差异。我们研究了两种宿主范围不同的相关多食性叶螨，即二斑叶螨（1200种植物）和截形叶螨（90种植物）。利用在菜豆上驯化并转移到新植物宿主（棉花、黄瓜、茄子）上的两个物种的多个种群的数据，来研究相对于基于种群的基因表达变化的转录可塑性。与截形叶螨相比，二斑叶螨表现出更高的转录可塑性。该物种的种群对植物宿主的反应也表现出更多可变的表达调控，特别是与解毒、转运和转录因子相关的基因。针对不同的植物宿主，这两种多食性物种都显示出药物/异生物质代谢过程的富集，二斑叶螨协调了相对更广泛的生物途径。通过共表达网络分析，我们确定了与宿主植物反应相关的基因模块，揭示了两种叶螨取食同一植物时主要参与解毒代谢的共享枢纽基因。在沉默与茄子暴露相关的共享枢纽CYP基因后，两种物种在原始菜豆宿主上的表现都有所改善，但截形叶螨在取食茄子时的繁殖力下降。二斑叶螨所显示的广泛转录组变异可能是该物种枢纽基因缺乏的一种潜在补偿机制。这项研究指出了广食性食草动物在转录组变异性方面的细微差异。
