普通小麦-十倍体长穗偃麦草衍生新品种抗赤霉病基因的分子鉴别

Molecular Identification of FHB Resistance Gene in Varieties Derived from Common Wheat-Thinopyrum ponticum Partial Amphiploid

【目的】赤霉病(Fusarium head blight,FHB)是世界范围内严重危害小麦生产的病害之一。十倍体长穗偃麦草(Thinopyrum ponticum)具有优良的赤霉病抗性,普通小麦-十倍体长穗偃麦草衍生新品种西农509、西农511和西农529在田间展现出较强的赤霉病抗性。本文旨在对这3个品种的赤霉病抗性基因进行分子鉴别,为它们在小麦赤霉病抗性遗传改良中的应用提供理论依据。【方法】通过赤霉病菌(Fusarium graminearum)人工接种鉴定,明确3个小麦新品种对赤霉病的抗性水平。利用偃麦草E组染色体(臂)第1—7同源群的特异引物对3个普通小麦-十倍体长穗偃麦草衍生新品种及其主要亲本小偃693、小偃597和十倍体长穗偃麦草进行分子鉴定,确定其长穗偃麦草的遗传区段。利用与长穗偃麦草7EL染色体上抗赤霉病基因Fhb7紧密连锁的标记对实验材料进行分析,明确该抗性基因与Fhb7的关系。【结果】鉴定结果表明,西农509、西农529和西农511的赤霉病抗性与中抗对照品种扬麦158的抗性水平相当,表现为中抗。105个长穗偃麦草E基因组特异标记中有7个在3个新品种中均能扩增出长穗偃麦草的特异条带,其中5个标记定位于7EL染色体臂上,2个标记定位于7ES染色体臂上。利用97个定位于7E染色体的特异标记进一步对小偃693、小偃597和3个新品种的遗传片段进行鉴别,结果表明20个标记能在5个长穗偃麦草衍生品种(系)扩增出稳定的十倍体长穗偃麦草的特异条带,其中包括与Fhb7紧密连锁的Xsdau K8、Xsdau K144、Xsdau K27、Xsdau K99、Xcfa2040和Xsdau K116等6个标记(7EL 149.00—7EL 153.77),即表明该区段源自于十倍体长穗偃麦草,跨距约89 c M。然而,已报道的7EL染色体臂末端与Fhb7两侧紧密连锁的分子标记Xsdau K60(7EL 153.77)、Xmag1932(7EL 154.70)、Xcfa2240(7EL 156.27)、Xsdau K66(7EL 158.02)、Xsdau K71(7EL 158.97)和Xsews19(7EL 160.00)等在3个新品种及小偃597中均没检出长穗偃麦草的特异条带。【结论】普通小麦-十倍体长穗偃麦草衍生新品种西农509、西农511和西农529具有较好的赤霉病抗性,携带来自于十倍体长穗偃麦草7E染色体的遗传区段,然而该抗赤霉病基因不同于Fhb7。

[Objective] Fusarium head blight（FHB） is one of the most devastating diseases of wheat. Thinopyrum ponticum is one of the important source resistance cultivars of wheat disease resistance breeding, with high tolerance to FHB. Three derived varieties of common wheat-Th. ponticum Xinong 509, Xinong 511 and Xinong 529 showed moderate resistance to FHB in field. The objective of this study is to clarify the genetic constitution of resistance gene in three varieties.[Method] Single drop injection with Fusarium graminearum was performed to detect the reaction of the three derived varieties of common wheat-Th. ponticum to FHB. Specific molecular markers located on homologous group 1 to 7 of Thinopyrum E chromosome were employed to detect the sources of resistance to FHB, screening the three derived varieties of common wheat-Th. ponticum, and their major donor parents Xiaoyan 693, Xiaoyan 597 and Th. ponticum. Specific molecular markers closely linked with flanking Fhb7 were used to analyze the relationship between the gene conferring resistance to FHB and Fhb7. [Result] Three derived varieties were moderately resistant to FHB in the field experiment, and had no much difference compared with the medium-resistant control variety. Seven of the 105 chromosome E specific molecular markers of Thinopyrum could be amplified polymorphism bands in the three derived varieties and Th. ponticum, which located on the chromosome 7 E. A total of 97 specific markers located on the chromosome 7 E, 20 showed specific bands of Th. ponticum in the three derived varieties of common wheat-Th. ponticum, and their major donor parents Xiaoyan 693, Xiaoyan 597. The results indicate that the 89 c M genetic fragment derived from Th. ponticum 7 E chromosome. Of them, six molecular markers（Xsdau K8, Xsdau K144, Xsdau K27, Xsdau K99, Xcfa2040 and Xsdau K116）, which were located on 7 EL 149.00-7 EL 153.77, tightly linked to Fhb7. However, Xsdau K60（7 EL 153.77）, Xmag1932（7 EL 154.70）, Xcfa2240（7 EL 156.27）, Xsdau K66（7 EL 158.02）, Xsdau K71（7 EL 158.97） and Xsews19（7 EL 160.00）, which are next to Fhb7, showed no specific bands of Th. ponticum among the three derived varieties of common wheat-Th. ponticum and Xiaoyan 597. [Conclusion] Xinong 509, Xinong 511 and Xinong 529, derived from Th. ponticum with good FHB resistance, possess a novel FHB resistance gene, which derived from Th. ponticum and was different from Fhb7.