Department of Horticulture and Crop Science, The Ohio State University and the Ohio Agriculture Research and Development Center, Wooster, Ohio 44691, USA.
Phytopathology. 2012 Mar;102(3):306-14. doi: 10.1094/PHYTO-05-11-0143.
Host resistance is the main way to control Fusarium head blight (FHB) in wheat. Despite improved levels of resistance to infection and spread in vegetative tissue, the toxin deoxynivalenol (DON) can still accumulate to unacceptable concentration levels. In this study, our objectives were to assess the genetic variation for resistance to kernel infection (RKI) and resistance to toxin accumulation (RTA) and their role in controlling DON. We collected spikes with different levels of visual symptoms from each of 32 wheat genotypes and at four environments and determined DON and fungal biomass (FB) from each sample. We assessed RKI by regressing FB on the level of visual symptoms and RTA by regressing DON on FB for each genotype. Significant genetic effects were found for RKI and RTA. Some genotypes consistently had low FB in their grain despite increasing visual symptoms suggesting RKI. Additionally, some genotypes consistently had low DON in their grain despite increasing FB levels suggesting a higher RTA in these genotypes. The variation for RKI and RTA explained a significant fraction of the variation for DON among genotypes with moderate visual symptoms using independent grain samples. Although RKI and RTA were significantly correlated (r = 0.58, P = 0.05), RTA was more predictive of DON accumulation because it modeled 32 to 44% of the genotype sum of squares for DON, while only 9 to 10% were predicted using RKI. Thus, variation for RTA was important in explaining variation for DON among genotypes with acceptable levels of resistance to fungal infection and spread. This work indicates that there is a need to develop a better understanding of RTA and rapid screening methods for this trait.
寄主抗性是控制小麦赤霉病（FHB）的主要方法。尽管在感染和营养组织传播方面的抗性水平有所提高，但真菌毒素脱氧雪腐镰刀菌烯醇（DON）仍可能积累到不可接受的浓度水平。在这项研究中，我们的目标是评估对籽粒感染（RKI）和毒素积累抗性（RTA）的遗传变异及其在控制 DON 中的作用。我们从 32 个小麦基因型中的每一个收集了具有不同视觉症状水平的穗，并在四个环境中进行了收集，从每个样本中测定 DON 和真菌生物量（FB）。我们通过将 FB 回归到视觉症状水平来评估 RKI，通过将 DON 回归到 FB 来评估 RTA。在 RKI 和 RTA 中均发现了显著的遗传效应。尽管观察到的视觉症状增加，但一些基因型的籽粒 FB 仍然较低，这表明 RKI 较低。此外，尽管 FB 水平增加，但一些基因型的籽粒 DON 仍然较低，这表明这些基因型的 RTA 较高。使用独立的籽粒样本，中等程度视觉症状的基因型之间 DON 的变异中，RKI 和 RTA 解释了很大一部分变异。尽管 RKI 和 RTA 呈显著相关（r = 0.58，P = 0.05），但 RTA 对 DON 积累的预测性更强，因为它可以模拟 DON 的基因型总和的 32%至 44%，而仅使用 RKI 预测了 9%至 10%。因此，在解释具有可接受的真菌感染和传播抗性的基因型之间 DON 的变异时，RTA 的变异性很重要。这项工作表明，需要更好地了解 RTA，并为此特性开发快速筛选方法。
