Naz Ali Ahmad, Kunert Antje, Lind Volker, Pillen Klaus, Léon Jens
Institute of Crop Science and Resource Conservation, Crop Genetics and Biotechnology Unit, University of Bonn, Katzenburgweg 5, 53115 Bonn, Germany.
Theor Appl Genet. 2008 May;116(8):1095-104. doi: 10.1007/s00122-008-0738-y.
The present study aimed to localize exotic quantitative trait locus (QTL) alleles for the improvement of leaf rust (P. triticina) resistance in an advanced backcross (AB) population, B22, which is derived from a cross between the winter wheat cultivar Batis (Triticum aestivum) and the synthetic wheat accession Syn022L. The latter was developed from hybridization of T. turgidum ssp. dicoccoides and T. tauschii. Altogether, 250 BC2F3 lines of B22 were assessed for seedling resistance against the leaf rust isolate 77WxR under controlled conditions. In addition, field resistance against leaf rust was evaluated by assessing symptom severity under natural infestation across multiple environments. Simultaneously, population B22 was genotyped with a total of 97 SSR markers, distributed over the wheat A, B and D genomes. The phenotype and genotype data were subjected to QTL analysis by applying a 3-factorial mixed model analysis of variance including the marker genotype as a fixed effect and the environments, the lines and the marker by environment interactions as random effects. The QTL analysis revealed six putative QTLs for seedling resistance and seven for field resistance. For seedling resistance, the effects of exotic QTL alleles improved resistance at all detected loci. The maximum decrease of disease symptoms (-46.3%) was associated with marker locus Xbarc149 on chromosome 1D. For field resistance, two loci had stable main effects across environments and five loci exhibited marker by environment interaction effects. The strongest effects were detected at marker locus Xbarc149 on chromosome 1D, at which the exotic allele decreased seedling symptoms by 46.3% and field symptoms by 43.6%, respectively. Some of the detected QTLs co-localized with known resistance genes, while others appear to be as novel resistance loci. Our findings indicate, that the exotic wheat accession Syn022L may be useful for the improvement of leaf rust resistance in cultivated wheat.
本研究旨在定位外来数量性状位点（QTL）等位基因，以改良一个高代回交（AB）群体B22对叶锈病（小麦条锈菌）的抗性，该群体源自冬小麦品种巴蒂斯（普通小麦）与人工合成小麦Syn022L的杂交。后者由圆锥小麦亚种二粒小麦与节节麦杂交培育而成。在可控条件下，共对B22群体的250个BC2F3株系进行了苗期对叶锈菌分离株77WxR的抗性评估。此外，通过在多个环境中自然侵染条件下评估症状严重程度，对叶锈病的田间抗性进行了评价。同时，利用总共97个SSR标记对群体B22进行基因分型，这些标记分布在小麦A、B和D基因组上。通过应用三因素混合方差分析进行QTL分析，将标记基因型作为固定效应，环境、株系以及标记与环境的互作作为随机效应。QTL分析揭示了6个假定的苗期抗性QTL和7个田间抗性QTL。对于苗期抗性，外来QTL等位基因在所有检测位点均提高了抗性。疾病症状的最大降幅（-46.3%）与1D染色体上的标记位点Xbarc149相关。对于田间抗性，两个位点在不同环境中具有稳定的主效应，五个位点表现出标记与环境的互作效应。在1D染色体上的标记位点Xbarc149检测到的效应最强，外来等位基因分别使苗期症状降低46.3%，田间症状降低43.6%。一些检测到的QTL与已知抗性基因共定位，而其他一些似乎是新的抗性位点。我们的研究结果表明，外来小麦种质Syn022L可能有助于改良栽培小麦对叶锈病的抗性。
