The danger of Sclerotium cepivorum lies in the strength of its survival structure: sclerotia. Sclerotia comprising hardened mycelium contains food reserves that allow it to remain dormant for long period, which makes the sclerotia-infested soil useless to grow any crop of the Allium species, including onion and garlic. This paper would be the first report on the application of two-photon fluorescence microscopy to the analysis of the structure of sclerotia from S. cepivorum. For this study and, in order to test the method, two different types of sclerotia were used: (1) sclerotia isolated from naturally infested soil and (2) sclerotia produced in vitro (from 20-day-old cultures). Both types of sclerotia were processed by cryopreservation and eight µm histological cuts were used to obtain an autofluorescence image. For both sclerotia, the fluorescence spectrum has three peak signals at their wall. Sclerotia from infested soil presented fluorescence peaks at 400-436, 436-475, and 515-575 nm, while signals from sclerotia produced in vitro presented fluorescence peaks at 400-442, 500-600, and 655-700 nm. Peaks at the violet electromagnetic region (400-436 and 400-442) are like that of the signals reported by the melanin. This study showed that two-photon microscopy is a novel and valuable tool for the study of sclerotia structure and their fluorescence signal, and the possibility of using it as a specific marker to direct detection in the field should be explored.

中文翻译：

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双光子显微镜在研究从自然侵染的土壤中分离并在体外产生的菌核中的应用

菌核的危险在于其生存结构的强度：菌核。包含硬化菌丝体的菌核含有食物储备，使其能够长时间保持休眠状态，这使得菌核感染的土壤无法种植任何葱属作物，包括洋葱和大蒜。这篇论文将是关于双光子荧光显微镜在 S.cepivorum 菌核结构分析中应用的第一份报告。在这项研究中，为了测试该方法，使用了两种不同类型的菌核：（1）从自然感染的土壤中分离的菌核和（2）体外产生的菌核（来自 20 天大的培养物）。两种类型的菌核都通过冷冻保存处理，并使用 8 µm 组织切片来获得自发荧光图像。对于两种菌核，荧光光谱在其壁上具有三个峰值信号。来自受感染土壤的菌核在 400-436、436-475 和 515-575 nm 处呈现荧光峰，而来自体外产生的菌核的信号在 400-442、500-600 和 655-700 nm 处呈现荧光峰。紫色电磁区（400-436 和 400-442）的峰值类似于黑色素报告的信号。该研究表明，双光子显微镜是研究菌核结构及其荧光信号的一种新颖且有价值的工具，应探索将其作为特异性标记物在现场进行直接检测的可能性。而来自体外产生的菌核的信号在 400-442、500-600 和 655-700 nm 处呈现荧光峰。紫色电磁区（400-436 和 400-442）的峰值类似于黑色素报告的信号。该研究表明，双光子显微镜是研究菌核结构及其荧光信号的一种新颖且有价值的工具，应探索将其作为特异性标记物在现场进行直接检测的可能性。而来自体外产生的菌核的信号在 400-442、500-600 和 655-700 nm 处呈现荧光峰。紫色电磁区（400-436 和 400-442）的峰值类似于黑色素报告的信号。该研究表明，双光子显微镜是研究菌核结构及其荧光信号的一种新颖且有价值的工具，应探索将其作为特异性标记物在现场进行直接检测的可能性。