Marcel Thierry C, Gorguet Benoît, Ta Minh Truong, Kohutova Zuzana, Vels Anton, Niks Rients E
Laboratory of Plant Breeding, Graduate School for Experimental Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
Department of Genetics and Breeding, Faculty of Agrobiology, Food and Nature Resourses, Czech University of Agriculture, Prague, Czech Republic.
New Phytol. 2008;177(3):743-755. doi: 10.1111/j.1469-8137.2007.02298.x. Epub 2007 Dec 7.
Partial resistance is considered race-nonspecific and durable, consistent with the concept of 'horizontal' resistance. However, detailed observations of partial resistance to leaf rust (Puccinia hordei) in barley (Hordeum vulgare) revealed small cultivar x isolate interactions, suggesting a minor-gene-for-minor-gene interaction model, similar to so-called 'vertical' resistance. Three consistent quantitative trait loci (QTLs), labelled Rphq2, Rphq3 and Rphq4, that were detected in the cross susceptible L94 x partially resistant Vada have been incorporated into the L94 background to obtain near-isogenic lines (NILs). Three isolates were used to map QTLs on seedlings of the L94 x Vada population and to evaluate the effect of each QTL on adult plants of the respective NILs under field conditions. Rphq2 had a strong effect in seedlings but almost no effect in adult plants, while Rphq3 was effective in seedlings and in adult plants against all three isolates. However, Rphq4 was effective in seedlings and in adult plants against two isolates but ineffective in both development stages against the third, demonstrating a clear and reproducible isolate-specific effect. The resistance governed by the three QTLs was not associated with a hypersensitive reaction. Those results confirm the minor-gene-for-minor-gene model suggesting specific interactions between QTLs for partial resistance and P. hordei isolates.
部分抗性被认为是品种非特异性且持久的，这与“水平”抗性的概念一致。然而，对大麦（Hordeum vulgare）对叶锈病（Puccinia hordei）的部分抗性进行的详细观察揭示了小的品种×分离株互作，这表明存在一种小基因对小基因的互作模型，类似于所谓的“垂直”抗性。在感病品种L94与部分抗病品种Vada的杂交后代中检测到的三个一致的数量性状位点（QTL），分别标记为Rphq2、Rphq3和Rphq4，已被导入L94背景中以获得近等基因系（NIL）。使用三个分离株在L94×Vada群体的幼苗上定位QTL，并在田间条件下评估每个QTL对相应NIL成年植株的影响。Rphq2在幼苗期有很强的作用，但在成年植株中几乎没有作用，而Rphq3在幼苗期和成年植株中对所有三个分离株都有效。然而，Rphq4在幼苗期和成年植株中对两个分离株有效，但在两个发育阶段对第三个分离株均无效，这表明存在明显且可重复的分离株特异性效应。由这三个QTL控制的抗性与过敏反应无关。这些结果证实了小基因对小基因模型，表明部分抗性的QTL与大麦叶锈菌分离株之间存在特异性互作。
