Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is a serious invasive pest of small‐grain cereals and many grass species. An efficient strategy to defy aphid attacks is to identify sources of natural resistance and transfer resistance genes into susceptible crop cultivars. Revealing the genes helps understand plant defense mechanisms and engineer plants with durable resistance to the pest. To date, more than 15 RWA resistance genes have been identified in wheat (Triticum aestivum L.) but none of them has been cloned. Previously, we genetically mapped the RWA resistance gene Dn2401 into an interval of 0.83 cM on the short arm of chromosome 7D and spanned it with five bacterial artificial chromosome (BAC) clones. Here, we used a targeted strategy combining traditional approaches toward gene cloning (genetic mapping and sequencing of BAC clones) with novel technologies, including optical mapping and long‐read nanopore sequencing. The latter, with reads spanning the entire length of a BAC insert, enabled us to assemble the whole region, a task that was not achievable with short reads. Long‐read optical mapping validated the DNA sequence in the interval and revealed a difference in the locus organization between resistant and susceptible genotypes. The complete and accurate sequence of the Dn2401 region facilitated the identification of new markers and precise annotation of the interval, revealing six high‐confidence genes. Identification of Epoxide hydrolase 2 as the most likely Dn2401 candidate opens an avenue for its validation through functional genomics approaches.

中文翻译：

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通过长读技术访问面包小麦中的俄罗斯小麦蚜虫抗性基因。

俄罗斯小麦蚜虫（RWA）（Diuraphis noxia Kurdjumov）是小谷物和许多草种的严重入侵害虫。抵抗蚜虫攻击的有效策略是识别天然抗药性并将抗性基因转移到易感作物品种中。揭示基因有助于了解植物防御机制，并设计出对害虫具有持久抗性的植物。迄今为止，已经在小麦（Triticum aestivum L.）中鉴定出超过15个RWA抗性基因，但是没有一个被克隆。以前，我们对RWA抗性基因Dn2401进行了基因定位在7D染色体的短臂上插入一个0.83 cM的区间，并跨越了五个细菌人工染色体（BAC）克隆。在这里，我们采用了针对性策略，将传统的基因克隆方法（BAC克隆的基因定位和测序）与新技术相结合，包括光学定位和长读纳米孔测序。后者的读取跨越BAC插入的整个长度，使我们能够组装整个区域，而短读取是无法实现的。长时间的光学作图验证了该间隔内的DNA序列，并揭示了抗性和易感基因型之间的基因座组织差异。Dn2401的完整而准确的序列该区域促进了新标记的鉴定和间隔的精确注释，揭示了六个高可信度基因。将环氧水解酶2鉴定为最可能的Dn2401候选基因，为通过功能基因组学方法进行验证打开了一条途径。