Department of Primary Industries and Regional Development, 3 Baron Hay Ct, South Perth, WA, 6151, Australia.
School of Agriculture and Environment, University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
Planta. 2024 May 29;260(1):13. doi: 10.1007/s00425-024-04444-9.
PM3 and PM8 alleles carried by two CIMMYT wheat lines confer powdery mildew resistance in seedlings and/or adult plants. A stage-specific epistatic interaction was observed between PM3 and PM8. Powdery mildew is an important foliar disease of wheat. Major genes for resistance, which have been widely used in wheat breeding programs, are typically effective against only limited numbers of virulence genes of the pathogen. The main aim of this study was to map resistance loci in wheat lines 7HRWSN58 and ZWW09-149 from the International Maize and Wheat Improvement Center (CIMMYT). Doubled haploid populations (Magenta/7HRWSN58 and Emu Rock/ZWW09-149) were developed and grown in controlled environment experiments and inoculated with a composite of Blumeria graminis f.sp. tritici isolates that had been collected at various locations in Western Australia. Plants were assessed for powdery mildew symptoms (percentage leaf area diseased) on seedlings and adult plants. Populations were subjected to genotyping-by-sequencing and assayed for known SNPs in the resistance gene PM3. Linkage maps were constructed, and markers were anchored to the wheat reference genome sequence. In both populations, there were asymptomatic lines that exhibited no symptoms. Among symptomatic lines, disease severity varied widely. In the Magenta/7HRWSN58 population, most of the observed variation was attributed to the PM3 region of chromosome 1A, with the allele from 7HRWSN58 conferring resistance in seedlings and adult plants. In the Emu Rock/ZWW09-149 population, two interacting quantitative trait loci were mapped: one at PM3 and the other on chromosome 1B. The Emu Rock/ZWW09-149 population was confirmed to segregate for a 1BL·1RS translocation that carries the PM8 powdery mildew resistance gene from rye. Consistent with previous reports that PM8-derived resistance can be suppressed by PM3 alleles, the observed interaction between the quantitative trait loci on chromosomes 1A and 1B indicated that the PM3 allele carried by ZWW09-149 suppresses PM8-derived resistance from ZWW09-149, but only at the seedling stage. In adult plants, the PM8 region conferred resistance regardless of the PM3 genotype. The resistance sources and molecular markers that were investigated here could be useful in wheat breeding.
PM3 和 PM8 等位基因赋予两个 CIMMYT 小麦品系幼苗和/或成株期对白粉病的抗性。在 PM3 和 PM8 之间观察到特定发育阶段的上位性互作。白粉病是小麦的一种重要叶部病害。已广泛用于小麦育种计划的抗源主效基因通常仅对病原菌的有限数量的毒性基因有效。本研究的主要目的是定位国际玉米小麦改良中心（CIMMYT）的小麦品系 7HRWSN58 和 ZWW09-149 中的抗性基因座。构建了加倍单倍体群体（Magenta/7HRWSN58 和 Emu Rock/ZWW09-149），并在受控环境实验中生长，然后用在西澳大利亚不同地点收集的小麦白粉病菌 Blumeria graminis f.sp. tritici 复合菌株进行接种。在幼苗和成株期对植株的白粉病症状（叶片发病面积百分比）进行评估。对群体进行基于测序的基因型分析，并对 PM3 抗性基因中的已知 SNP 进行检测。构建了连锁图谱，并将标记锚定到小麦参考基因组序列上。在两个群体中，都有无症状的品系，没有表现出症状。在有症状的品系中，病情严重程度差异很大。在 Magenta/7HRWSN58 群体中，观察到的大多数变异归因于 1A 染色体的 PM3 区域，来自 7HRWSN58 的等位基因赋予幼苗和成株期的抗性。在 Emu Rock/ZWW09-149 群体中，定位到两个互作的数量性状位点：一个在 PM3 区域，另一个在 1B 染色体上。Emu Rock/ZWW09-149 群体被证实分离出携带来自黑麦的 PM8 白粉病抗性基因的 1BL·1RS 易位。与之前报道的 PM8 衍生的抗性可被 PM3 等位基因抑制的结果一致，在 1A 和 1B 染色体上观察到的数量性状位点之间的相互作用表明，来自 ZWW09-149 的 ZWW09-149 携带的 PM3 等位基因抑制来自 ZWW09-149 的 PM8 衍生的抗性，但仅在幼苗期。在成株期，PM8 区域赋予抗性，而与 PM3 基因型无关。本研究中调查的抗性来源和分子标记可用于小麦育种。
