Background

Rice sheath blight (ShB) disease, caused by the pathogenic fungus Rhizoctonia solani, causes significant yield losses globally. US weedy rice populations, which are de-domesticated forms of indica and aus cultivated rice, appear to be more resistant to ShB than local japonica cultivated rice. We mapped quantitative trait loci (QTL) associated with ShB resistance using two F₈ recombinant inbred line populations generated from crosses of an indica crop variety, Dee-Geo-Woo-Gen (DGWG), with individuals representing the two major US weed biotypes, straw hull (SH) and black hull awned (BHA).

Results

We identified nine ShB resistance QTL across both mapping populations. Five were attributable to alleles that affect plant height (PH) and heading date (HD), two growth traits that are known to be highly correlated with ShB resistance. By utilizing an approach that treated growth traits as covariates in the mapping model, we were able to infer that the remaining four QTL are involved in ShB resistance. Two of these, qShB1–2 and qShB4, are different from previously identified ShB QTL and represent new candidates for further study.

Conclusion

Our findings suggest that ShB resistance can be improved through favorable plant growth traits and the combined effects of small to moderate-effect resistance QTL. Additionally, we show that including PH and HD as covariates in QTL mapping models is a powerful way to identify new ShB resistance QTL.

中文翻译：

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赋予两个杂草稻作图群体抗白叶枯病新QTL的鉴定

背景

由病原性真菌Rhizoctonia solani引起的水稻鞘枯病（ShB）病害在全球范围内造成重大的产量损失。美国杂草稻的人群，这是去驯化形式籼稻和AUS栽培稻，似乎对纹枯病比本地更耐粳稻栽培稻。我们映射数量性状基因座与进行两个F纹枯病抗性相关（QTL）_8个从一个杂交产生的重组自交系群体籼稻作物品种，迪-地理佑根（DGWG）中，用表示两个主要的美国杂草生物型的个体，稻草壳（SH）和黑壳篷（BHA）。

结果

我们在这两个作图群体中鉴定出9个ShB抵抗QTL。五个归因于影响植物高度（PH）和抽穗期（HD）的等位基因，这两个生长性状与ShB抗性高度相关。通过使用在映射模型中将生长性状视为协变量的方法，我们能够推断出其余四个QTL均与ShB抗性有关。其中qShB1-2和qShB4这两个与以前确定的ShB QTL不同，它们代表了进一步研究的新对象。

结论

我们的研究结果表明，可以通过有利的植物生长性状和中低效抗性QTL的综合作用来提高对ShB的抗性。此外，我们表明在QTL映射模型中将PH和HD作为协变量包括是识别新的ShB抗性QTL的有效方法。