Guo Yan, Du Ziyi, Chen Jiang, Zhang Zhongjun
Plant Pathology Department, College of Plant Protection, China Agricultural University, Beijing, China.
PLoS One. 2017 Apr 6;12(4):e0174939. doi: 10.1371/journal.pone.0174939. eCollection 2017.
Sheath blight is one of the most devastating wheat diseases worldwide. Breeding resistant cultivars is the most powerful strategy to defeat the disease. Plant resistance on "disease escape" works through modulation of morphological traits and shows sustainable resistance to disease. Plant architectural traits have been reported to play a significant role in disease response. Therefore, exploring the genetic relationship between plant architecture and disease resistance is of importance to the understanding of plant resistance via "disease escape". Using an F9 population of 266 RILs (Recombinant Inbred Lines) derived from the cross of Luke × AQ24788-83, we have generated a linkage map of 631 markers on 21 chromosomes. In this study, we present the QTL identification of fourteen plant architectural characteristics and heading time from two years and analyze their genetic relationships with seven previously published QTLs to sheath blight (QSBs, QSe.cau), including plant height (PH), the space between the flag leaf and penultimate leaf (fdR), heading date (Hd), and other traits. Twelve stable QTLs of the morphological traits were identified with good consistency across five replicates. For the seven previously published QSBs, we found no significant association with plant height. However, some of the QSBs displayed strong associations with plant architectural traits and heading date. Especially, QfdR.cau-1AS, QHd.cau-2BS, QfdR.cau-5DL, and QfdR.cau-6BL were respectively mapped to the same regions as QSe.cau-1AS, QSe.cau-2BS, QSe.cau-5DL, and QSe.cau-6BL. Taken together, we have demonstrated that plant height did not exert a direct influence on the resistance to sheath blight conferred by the seven QSBs and that the plant architecture and heading date did exhibit a tight relationship with the resistance. Therefore, this study provides a novel evidence to help understand sheath blight resistance in wheat. In addition, the linked morphological characteristics and the generated flanking markers will facilitate breeding for resistance to sheath blight in wheat.
纹枯病是全球最具毁灭性的小麦病害之一。培育抗病品种是战胜该病害的最有效策略。植物基于“避病”的抗性通过调节形态性状起作用，并表现出对病害的可持续抗性。据报道，植物株型性状在病害反应中起重要作用。因此，探索植物株型与抗病性之间的遗传关系对于理解植物通过“避病”实现的抗性具有重要意义。利用由Luke×AQ24788 - 83杂交产生的包含266个重组自交系（RILs）的F9群体，我们构建了一个在21条染色体上有631个标记的连锁图谱。在本研究中，我们展示了连续两年对14个植物株型特征和抽穗期的QTL鉴定，并分析了它们与之前发表的7个纹枯病QTL（QSBs、QSe.cau）的遗传关系，这些QTL包括株高（PH）、旗叶与倒数第二叶之间的间距（fdR）、抽穗日期（Hd）以及其他性状。在五个重复实验中鉴定出12个形态性状的稳定QTL，一致性良好。对于之前发表的7个QSBs，我们发现它们与株高没有显著关联。然而，一些QSBs与植物株型性状和抽穗日期表现出强烈关联。特别是，QfdR.cau - 1AS、QHd.cau - 2BS、QfdR.cau - 5DL和QfdR.cau - 6BL分别被定位到与QSe.cau - 1AS、QSe.cau - 2BS、QSe.cau - 5DL和QSe.cau - 6BL相同的区域。综上所述，我们证明了株高对7个QSBs赋予的纹枯病抗性没有直接影响，并且植物株型和抽穗日期确实与抗性表现出紧密关系。因此，本研究为帮助理解小麦纹枯病抗性提供了新的证据。此外，连锁的形态特征和产生的侧翼标记将有助于小麦纹枯病抗性育种。
