Fusarium head blight (FHB), mainly incited by Fusarium graminearum Schwabe, has caused great losses in grain yield and quality of wheat globally. Fhb7, a gene with a major effect on FHB resistance, was recently cloned and shown to be a GST encoding glutathione S-transferase. Fhb7 originated from the 7E chromosome of Thinopyrum ponticum and confers broad resistance to Fusarium species. However, high-throughput diagnostic markers are not available for wider deployment of Fhb7 in breeding programs. To develop such DNA markers for high-throughput screening of Fhb7, we designed two kompetitive allele specific polymerase chain reaction (KASP) markers (Fhb7-KASP1 and Fhb7-KASP2) based on the promoter and coding sequences of GST homologs and tested their cosegregation with Fhb7 FHB resistance in a recombinant inbred population. As a validation of their usefulness in marker-assisted selection in breeding programs, Fhb7-KASP1 and Fhb7-KASP2 were shown to be diagnostic for Fhb7 status in a set of RWG34-near-isogenic lines (NILs) and a natural winter wheat population (RGON2020). Haplotype analysis of Thinopyrum accessions using the two markers and GST homolog sequences identified only six accessions with the Fhb7 resistance marker alleles and the Hap I-R haplotype, and five of them were cytologically confirmed to be Th. ponticum, the species in which Fhb7 was originally identified. The development of the diagnostic markers in this study will facilitate the deployment of Fhb7 in wheat breeding programs to improve FHB resistance.

中文翻译：

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小麦枯萎病抗性基因 Fhb7 诊断标志物的开发与验证

主要由禾谷镰刀菌引起的赤霉病（FHB）已在全球范围内造成小麦产量和品质的巨大损失。Fhb7是一种对 FHB 抗性具有主要影响的基因，最近被克隆并显示为GST编码谷胱甘肽 S-转移酶。Fhb7起源于Thinopyrum ponticum的7E染色体，对镰刀菌具有广泛的抗性。然而，高通量诊断标记不能用于在育种计划中更广泛地部署Fhb7 。开发用于Fhb7高通量筛选的此类 DNA 标记，我们基于GST同源物的启动子和编码序列设计了两个竞争性等位基因特异性聚合酶链反应 (KASP) 标记（Fhb7-KASP1 和 Fhb7-KASP2），并在重组近交种群中测试了它们与Fhb7 FHB 抗性的共分离。作为对其在育种计划中标记辅助选择的有用性的验证，Fhb7-KASP1 和 Fhb7-KASP2 被证明可诊断一组 RWG34 近等基因系 (NIL) 和天然冬小麦种群中的Fhb7状态。 RGON2020)。使用这两个标记和GST同源序列对Thinopyrum种质进行单倍型分析，仅鉴定了 6 个具有Fhb7的种质抗性标记等位基因和Hap IR单倍型，其中5个经细胞学证实为Th。ponticum ，最初鉴定出Fhb7的物种。本研究中诊断标记的开发将促进Fhb7在小麦育种计划中的部署，以提高 FHB 抗性。