Background Breeding of rice with panicle resistance to rice blast disease caused by Pyricularia oryzae is a challenge towards sustainable rice production. Methods for accurate estimation of disease severity can support breeding. White head symptoms are a commonly used index of panicle blast in the field. As the development mechanism of this symptom remains unclear, we used cut-flower dye (CFD) solution to visualize the infected panicle tissues. Results CFD delineated the edge of white head symptoms in rice panicles artificially infected with P. oryzae. Hyphae within the tissues were confirmed through staining with a fluorescent wheat germ agglutinin conjugate. Hyphal density was obviously diminished at the dye edge. Growing hyphae preferred to move along the vascular bundles; infected tissues lost the ability to transport water, leading to white head formation. By marking the edge of the white heads, this simple dyeing technique precisely reveals the extent of infection. Further, digital imaging allowed dried samples to be stored and reassessed later. Conclusions The CFD detection technique served as a powerful tool for estimating disease severity by color, as it clearly revealed lesions in both the panicles and leaves. Combined with reliable methods for artificial inoculation and observation of infecting hyphae, this technique will advance the research and breeding of panicle blast-resistant rice.

中文翻译：

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用切花染料检测稻瘟病菌引起的白头病。

背景 培育具有抗稻瘟病抗性的水稻是对可持续水稻生产的挑战。准确估计疾病严重程度的方法可以支持育种。白头症状是田间穗瘟的常用指标。由于这种症状的发展机制仍不清楚，我们使用切花染料 (CFD) 溶液来可视化受感染的圆锥花序组织。结果 CFD 描绘了米假单胞菌人工侵染的水稻穗部白头症状的边缘。通过用荧光小麦胚芽凝集素缀合物染色确认组织内的菌丝。菌丝密度在染料边缘明显减少。生长的菌丝倾向于沿着维管束移动；受感染的组织失去了运输水的能力，导致白头形成。通过标记白头的边缘，这种简单的染色技术准确地揭示了感染的程度。此外，数字成像允许储存干燥的样品并在以后重新评估。结论 CFD 检测技术是通过颜色评估疾病严重程度的有力工具，因为它清楚地揭示了圆锥花序和叶片中的病变。结合可靠的人工接种方法和侵染菌丝观察，该技术将推动抗穗稻瘟病水稻的研究和育种。结论 CFD 检测技术是通过颜色评估疾病严重程度的有力工具，因为它清楚地揭示了圆锥花序和叶片中的病变。结合可靠的人工接种方法和侵染菌丝观察，该技术将推动抗穗稻瘟病水稻的研究和育种。结论 CFD 检测技术是通过颜色评估疾病严重程度的有力工具，因为它清楚地揭示了圆锥花序和叶片中的病变。结合可靠的人工接种方法和侵染菌丝观察，该技术将推动抗穗稻瘟病水稻的研究和育种。