National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
PLoS One. 2013 Jul 10;8(7):e68150. doi: 10.1371/journal.pone.0068150. Print 2013.
Meta-analysis was performed for three major foliar diseases with the aim to find out the total number of QTL responsible for these diseases and depict some real QTL for molecular breeding and marker assisted selection (MAS) in maize. Furthermore, we confirmed our results with some major known disease resistance genes and most well-known gene family of nucleotide binding site (NBS) encoding genes. Our analysis revealed that disease resistance QTL were randomly distributed in maize genome, but were clustered at different regions of the chromosomes. Totally 389 QTL were observed for these three major diseases in diverse maize germplasm, out of which 63 QTL were controlling more than one disease revealing the presence of multiple disease resistance (MDR). 44 real-QTLs were observed based on 4 QTL as standard in a specific region of genome. We also confirmed the Ht1 and Ht2 genes within the region of real QTL and 14 NBS-encoding genes. On chromosome 8 two NBS genes in one QTL were observed and on chromosome 3, several cluster and maximum MDR QTL were observed indicating that the apparent clustering could be due to genes exhibiting pleiotropic effect. Significant relationship was observed between the number of disease QTL and total genes per chromosome based on the reference genome B73. Therefore, we concluded that disease resistance genes are abundant in maize genome and these results can unleash the phenomenon of MDR. Furthermore, these results could be very handy to focus on hot spot on different chromosome for fine mapping of disease resistance genes and MAS.
进行了三个主要叶部病害的荟萃分析，目的是找出这些病害的 QTL 总数，并为玉米的分子育种和标记辅助选择（MAS）描绘一些实际的 QTL。此外，我们使用一些主要的已知抗病基因和最知名的核苷酸结合位点（NBS）编码基因家族来验证我们的结果。我们的分析表明，抗病 QTL 在玉米基因组中随机分布，但在染色体的不同区域聚集。在不同的玉米种质资源中，总共观察到 389 个控制这三种主要病害的 QTL，其中 63 个 QTL控制着一种以上的病害，显示出多种抗病性（MDR）的存在。根据基因组特定区域的 4 个 QTL 标准，共观察到 44 个实际 QTL。我们还在实际 QTL 区域内确认了 Ht1 和 Ht2 基因以及 14 个 NBS 编码基因。在第 8 号染色体上，一个 QTL 中观察到两个 NBS 基因，在第 3 号染色体上，观察到几个聚类和最大的 MDR QTL，表明明显的聚类可能是由于表现出多效性的基因。基于参考基因组 B73，观察到疾病 QTL 的数量与每条染色体上的总基因之间存在显著关系。因此，我们得出结论，抗病基因在玉米基因组中丰富，这些结果可以揭示 MDR 的现象。此外，这些结果对于针对不同染色体上的热点进行抗病基因的精细图谱绘制和 MAS 非常有用。
