Zhu Xianwen, Boehm Jeffrey D, Zhong Shaobin, Cai Xiwen
Dep. of Plant Sciences, North Dakota State Univ., Fargo, ND, 58108, USA.
current address: Institute of Advanced Agricultural Sciences, Peking Univ., Weifang, Shandong, 261000, P. R. China.
Plant Genome. 2022 Jun;15(2):e20183. doi: 10.1002/tpg2.20183. Epub 2022 Mar 1.
Hexaploid-derived resistance genes exhibit complex inheritance and expression patterns in tetraploid backgrounds. This study aimed to characterize the inheritance patterns and genomic compatibilities of hexaploid-derived Fusarium head blight (FHB) resistance genes in tetraploid durum wheat (Triticum durum Desf.). Evaluation of FHB resistance for F hybrids of hexaploid 'Sumai 3' crossed with tetraploid and hexaploid wheats indicated that Sumai 3-derived FHB resistance genes exhibit a dominant phenotypic effect seen only in hexaploid hybrids. Alternately, the hexaploid-derived FHB resistance genes from PI 277012 exhibited complete dominance in the crosses with both tetraploid and hexaploid wheat. FHB evaluation of the F hybrids of Sumai 3 and PI 277012 crossed with 'Langdon' (LDN)-'Chinese Spring' D-genome substitution lines suggested that chromosomes 2B, 3B, 4B, 5B, 6B, 3A, 4A, 6A, and 7A contain genes that suppress expression of the Sumai 3-derived FHB resistance, whereas chromosomes 4A, 6A, and 6B contain genes required for expression of PI 277012-derived FHB resistance. A wide range of segregation for FHB severity (10-90%) was observed in the F generation of Sumai 3 crossed with durum cultivars LDN and 'Divide', but the distribution of F families derived from the most resistant F segregants was skewed towards susceptibility. Similar segregation trends were observed in the crosses of PI 277012 with other durum wheats, whereby FHB resistance became slightly diluted over successive generations. These results suggest tetraploid durum wheat contains the unique alleles at multiple gene loci on different chromosomes that positively and/or negatively regulate the expression of hexaploid-derived FHB resistance genes, which complicate efforts to deploy these genes in durum breeding programs.
六倍体衍生的抗性基因在四倍体背景下呈现出复杂的遗传和表达模式。本研究旨在表征四倍体硬粒小麦（Triticum durum Desf.）中六倍体衍生的赤霉病（FHB）抗性基因的遗传模式和基因组兼容性。对六倍体‘苏麦3号’与四倍体和六倍体小麦杂交的F1杂种进行FHB抗性评估表明，苏麦3号衍生的FHB抗性基因表现出仅在六倍体杂种中可见的显性表型效应。另外，来自PI 277012的六倍体衍生FHB抗性基因在与四倍体和六倍体小麦的杂交中均表现出完全显性。对苏麦3号和PI 277012与‘兰登’（LDN）-‘中国春’D基因组代换系杂交的F1杂种进行FHB评估表明，2B、3B、4B、5B、6B、3A、4A、6A和7A染色体含有抑制苏麦3号衍生FHB抗性表达的基因，而4A、6A和6B染色体含有PI 277012衍生FHB抗性表达所需的基因。在苏麦3号与硬粒小麦品种LDN和‘迪瓦德’杂交的F2代中观察到FHB严重程度的广泛分离（10%-90%），但来自最抗病F2分离株的F3家系分布偏向感病。在PI 277012与其他硬粒小麦的杂交中也观察到类似的分离趋势，即FHB抗性在连续几代中略有稀释。这些结果表明，四倍体硬粒小麦在不同染色体的多个基因座上含有独特的等位基因，这些等位基因正向和/或负向调节六倍体衍生FHB抗性基因的表达，这使得在硬粒小麦育种计划中部署这些基因的努力变得复杂。
