Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
USDA-ARS Sustainable Agricultural Systems Laboratory, Beltsville, MD, USA.
BMC Genomics. 2024 Feb 28;25(1):221. doi: 10.1186/s12864-024-10128-1.
Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are components of the wheat streak mosaic virus disease complex in the Great Plains region of the U.S.A. and elsewhere. Co-infection of wheat with WSMV and TriMV causes synergistic interaction with more severe disease symptoms compared to single infections. Plants are equipped with multiple antiviral mechanisms, of which regulation of microRNAs (miRNAs) is a potentially effective constituent. In this investigation, we have analyzed the total and relative expression of miRNA transcriptome in two wheat cultivars, Arapahoe (susceptible) and Mace (temperature-sensitive-resistant), that were mock-inoculated or inoculated with WSMV, TriMV, or both at 18 °C and 27 °C.
Our results showed that the most abundant miRNA family among all the treatments was miRNA166, followed by 159a and 168a, although the order of the latter two changed depending on the infections. When comparing infected and control groups, twenty miRNAs showed significant upregulation, while eight miRNAs were significantly downregulated. Among them, miRNAs 9670-3p, 397-5p, and 5384-3p exhibited the most significant upregulation, whereas miRNAs 319, 9773, and 9774 were the most downregulated. The comparison of infection versus the control group for the cultivar Mace showed temperature-dependent regulation of these miRNAs. The principal component analysis confirmed that less abundant miRNAs among differentially expressed miRNAs were strongly correlated with the inoculated symptomatic wheat cultivars. Notably, miRNAs 397-5p, 398, and 9670-3p were upregulated in response to WSMV and TriMV infections, an observation not yet reported in this context. The significant upregulation of these three miRNAs was further confirmed with RT-qPCR analysis; in general, the RT-qPCR results were in agreement with our computational analysis. Target prediction analysis showed that the miRNAs standing out in our analysis targeted genes involved in defense response and regulation of transcription.
Investigation into the roles of these miRNAs and their corresponding targets holds promise for advancing our understanding of the mechanisms of virus infection and possible manipulation of these factors for developing durable virus resistance in crop plants.
小麦线条花叶病毒（WSMV）和小麦花叶病毒（TriMV）是美国大平原地区和其他地区小麦线条花叶病毒病复合体的组成部分。与单一感染相比，小麦同时感染 WSMV 和 TriMV 会导致协同作用，出现更严重的病症。植物具有多种抗病毒机制，其中 miRNA（microRNA）的调控是一种潜在有效的组成部分。在这项研究中，我们分析了在 18°C 和 27°C 下，模拟接种或接种 WSMV、TriMV 或两者的两个小麦品种（易感的 Arapahoe 和热敏抗性的 Mace）的 miRNA 转录组的总表达和相对表达。
我们的结果表明，在所有处理中，最丰富的 miRNA 家族是 miRNA166，其次是 159a 和 168a，尽管后两者的顺序因感染而异。在比较感染组和对照组时，有 20 个 miRNA 表现出显著上调，而 8 个 miRNA 则显著下调。其中，miRNA9670-3p、397-5p 和 5384-3p 表现出最显著的上调，而 miRNA319、9773 和 9774 则下调最多。与对照相比，Mace 品种的感染显示出这些 miRNA 的温度依赖性调控。主成分分析证实，差异表达 miRNA 中较少的 miRNA 与接种有症状的小麦品种强烈相关。值得注意的是，miRNA397-5p、398 和 9670-3p 对 WSMV 和 TriMV 的感染呈上调反应，这在该背景下尚未有报道。这些三个 miRNA 的显著上调通过 RT-qPCR 分析进一步得到证实；总的来说，RT-qPCR 结果与我们的计算分析一致。靶标预测分析表明，我们分析中突出的 miRNA 靶向参与防御反应和转录调控的基因。
研究这些 miRNA 及其对应靶标的作用有望深入了解病毒感染的机制，并有可能操纵这些因素，从而在作物植物中开发持久的抗病毒性。
