Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou, Shandong, 253023, China.
National Key Laboratory of Wheat Improvement, Shandong Agricultural University, Tai'an, Shandong, 271018, China.
BMC Plant Biol. 2024 Apr 18;24(1):297. doi: 10.1186/s12870-024-04993-x.
Developing and enriching genetic resources plays important role in the crop improvement. The flag leaf affects plant architecture and contributes to the grain yield of wheat (Triticum aestivum L.). The genetic improvement of flag leaf traits faces problems such as a limited genetic basis. Among the various genetic resources of wheat, Thinopyrum intermedium has been utilized as a valuable resource in genetic improvement due to its disease resistance, large spikes, large leaves, and multiple flowers. In this study, a recombinant inbred line (RIL) population was derived from common wheat Yannong15 and wheat-Th. intermedium introgression line SN304 was used to identify the quantitative trait loci (QTL) for flag leaf-related traits.
QTL mapping was performed for flag leaf length (FLL), flag leaf width (FLW) and flag leaf area (FLA). A total of 77 QTLs were detected, and among these, 51 QTLs with positive alleles were contributed by SN304. Fourteen major QTLs for flag leaf traits were detected on chromosomes 2B, 3B, 4B, and 2D. Additionally, 28 QTLs and 8 QTLs for flag leaf-related traits were detected in low-phosphorus and drought environments, respectively. Based on major QTLs of positive alleles from SN304, we identified a pair of double-ended anchor primers mapped on chromosome 2B and amplified a specific band of Th. intermedium in SN304. Moreover, there was a major colocated QTL on chromosome 2B, called QFll/Flw/Fla-2B, which was delimited to a physical interval of approximately 2.9 Mb and contained 20 candidate genes. Through gene sequence and expression analysis, four candidate genes associated with flag leaf formation and growth in the QTL interval were identified.
These results promote the fine mapping of QFll/Flw/Fla-2B, which have pleiotropic effects, and will facilitate the identification of candidate genes for flag leaf-related traits. Additionally, this work provides a theoretical basis for the application of Th. intermedium in wheat breeding.
开发和丰富遗传资源在作物改良中起着重要作用。旗叶影响植物结构，对小麦（Triticum aestivum L.）的产量有贡献。旗叶性状的遗传改良面临遗传基础有限等问题。在小麦的各种遗传资源中，中间偃麦草已被用作遗传改良的宝贵资源，因为它具有抗病性、大穗、大叶片和多花。本研究以普通小麦扬麦 15 为材料，构建了重组自交系群体，利用其与中间偃麦草的易位系 SN304 对旗叶相关性状进行了数量性状位点（QTL）分析。
对旗叶长（FLL）、旗叶宽（FLW）和旗叶面积（FLA）进行了 QTL 作图。共检测到 77 个 QTL，其中 SN304 贡献的正效等位基因 51 个。在 2B、3B、4B 和 2D 染色体上检测到 14 个旗叶性状的主效 QTL。此外，在低磷和干旱环境下分别检测到 28 个和 8 个与旗叶相关的 QTL。基于 SN304 的正效等位基因的主效 QTL，我们在染色体 2B 上找到了一对双端锚定引物，并在 SN304 中扩增到中间偃麦草的特异条带。此外，在染色体 2B 上还检测到一个主效共定位 QTL，称为 QFll/Flw/Fla-2B，其物理区间约为 2.9 Mb，包含 20 个候选基因。通过基因序列和表达分析，在 QTL 区间鉴定到与旗叶形成和生长相关的 4 个候选基因。
这些结果促进了对具有多效性的 QFll/Flw/Fla-2B 的精细定位，有助于鉴定与旗叶相关性状的候选基因。此外，本研究为中间偃麦草在小麦育种中的应用提供了理论依据。
