Department of Entomology, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
Wheat, Sorghum, and Forage Research Unit, USDA-ARS, Lincoln, NE 68583, USA.
Int J Mol Sci. 2020 Oct 27;21(21):7966. doi: 10.3390/ijms21217966.
Yellow sugarcane aphid (YSA) (, Forbes) is a damaging pest on many grasses. Switchgrass ( L.), a perennial C4 grass, has been selected as a bioenergy feedstock because of its perceived resilience to abiotic and biotic stresses. Aphid infestation on switchgrass has the potential to reduce the yields and biomass quantity. Here, the global defense response of switchgrass cultivars Summer and Kanlow to YSA feeding was analyzed by RNA-seq and metabolite analysis at 5, 10, and 15 days after infestation. Genes upregulated by infestation were more common in both cultivars compared to downregulated genes. In total, a higher number of differentially expressed genes (DEGs) were found in the YSA susceptible cultivar (Summer), and fewer DEGs were observed in the YSA resistant cultivar (Kanlow). Interestingly, no downregulated genes were found in common between each time point or between the two switchgrass cultivars. Gene co-expression analysis revealed upregulated genes in Kanlow were associated with functions such as flavonoid, oxidation-response to chemical, or wax composition. Downregulated genes for the cultivar Summer were found in co-expression modules with gene functions related to plant defense mechanisms or cell wall composition. Global analysis of defense networks of the two cultivars uncovered differential mechanisms associated with resistance or susceptibility of switchgrass in response to YSA infestation. Several gene co-expression modules and transcription factors correlated with these differential defense responses. Overall, the YSA-resistant Kanlow plants have an enhanced defense even under aphid uninfested conditions.
黄脊甘蔗绵蚜（YSA）（Forbes）是许多禾本科植物的有害害虫。柳枝稷（L.）是一种多年生 C4 禾本科植物，因其对非生物和生物胁迫的潜在抗性而被选为生物能源饲料。蚜虫对柳枝稷的侵害有可能降低产量和生物量。在这里，通过 RNA-seq 和代谢物分析，分析了柳枝稷品种 Summer 和 Kanlow 对 YSA 取食的全球防御反应，分别在取食后 5、10 和 15 天进行分析。与下调基因相比，受侵染上调的基因在两个品种中更为常见。总共，在 YSA 易感品种（Summer）中发现了更多的差异表达基因（DEGs），而在 YSA 抗性品种（Kanlow）中观察到的 DEGs 较少。有趣的是，在每个时间点或在两个柳枝稷品种之间没有发现共同下调的基因。基因共表达分析表明，Kanlow 上调的基因与类黄酮、对化学物质的氧化反应或蜡组成等功能有关。夏季品种下调的基因在与植物防御机制或细胞壁组成相关的基因功能的共表达模块中发现。对两个品种防御网络的全面分析揭示了与柳枝稷对 YSA 侵害的抗性或敏感性相关的不同机制。几个基因共表达模块和转录因子与这些差异防御反应相关。总的来说，YSA 抗性的 Kanlow 植物即使在没有蚜虫侵害的情况下也具有增强的防御能力。
