State Key Laboratory of Crop Stress Biology for Arid Areas (Northwest A&F University), Yangling, 712100, Shaanxi, China.
College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China.
BMC Genomics. 2020 Aug 6;21(1):546. doi: 10.1186/s12864-020-06950-y.
Many insects can develop differential biotypes on variable host plants, but the underlying molecular factors and mechanisms are not well understood. To address this issue, transcriptome profiling analyses were conducted for two biotypes of the cereal aphid, Sitobion avenae (Fabricius), on both original and alternative plants.
Comparisons between both biotypes generated 4174 differentially expressed unigenes (DEGs). In their response to host plant shift, 39 DEGs were shared by both biotypes, whereas 126 and 861 DEGs occurred only in biotypes 1 and 3, respectively. MMC (modulated modularity clustering) analyses showed that specific DEGs of biotypes 1 and 3 clustered into five and nine transcriptional modules, respectively. Among these DEGs, defense-related genes underwent intensive expression restructuring in both biotypes. However, biotype 3 was found to have relatively lower gene transcriptional plasticity than biotype 1. Gene enrichment analyses of the abovementioned modules showed functional divergence in defensive DEGs for the two biotypes in response to host transfer. The expression plasticity for some defense related genes was showed to be directly related to fecundity of S. avenae biotypes on both original and alternative plants, suggesting that expression plasticity of key defensive genes could have significant impacts on the adaptive potential and differentiation of S. avenae biotypes on different plants.
The divergence patterns of transcriptional plasticity in defense related genes may play important roles in the phenotypic evolution and differentiation of S. avenae biotypes. Our results can provide insights into the role of gene expression plasticity in the divergence of insect biotypes and adaptive evolution of insect populations.
许多昆虫可以在不同的宿主植物上产生不同的生物型，但潜在的分子因素和机制尚不清楚。为了解决这个问题，我们对两种不同生物型的麦长管蚜进行了转录组谱分析，这些生物型在原始和替代植物上都有生长。
两种生物型之间的比较共产生了 4174 个差异表达的基因。在对宿主植物转移的反应中，两种生物型共有 39 个差异表达基因，而分别只有 126 个和 861 个差异表达基因仅存在于生物型 1 和 3 中。MMC（调制模块聚类）分析表明，生物型 1 和 3 的特定差异表达基因分别聚类为五个和九个转录模块。在这些差异表达基因中，防御相关基因在两种生物型中都经历了强烈的表达重构。然而，与生物型 1 相比，生物型 3 的基因转录可塑性较低。对上述模块的基因富集分析表明，两种生物型在应对宿主转移时，防御相关差异表达基因的功能发生了分化。一些防御相关基因的表达可塑性与麦长管蚜在原始和替代植物上的繁殖力直接相关，这表明关键防御基因的表达可塑性可能对麦长管蚜生物型在不同植物上的适应潜力和分化产生重大影响。
防御相关基因转录可塑性的分化模式可能在麦长管蚜生物型的表型进化和分化中发挥重要作用。我们的研究结果为研究基因表达可塑性在昆虫生物型分化和昆虫种群适应性进化中的作用提供了新的思路。
