Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Wellington Rd, Clayton, Vic., 3800, Australia.
Centre for Biospectroscopy, School of Chemistry, Monash University, Wellington Rd, Clayton, Vic., 3800, Australia.
Sci Rep. 2018 Feb 9;8(1):2691. doi: 10.1038/s41598-018-20928-7.
Localisation of metabolites in sorghum coleoptiles using Raman hyperspectral imaging analysis was compared in wild type plants and mutants that lack cyanogenic glucosides. This novel method allows high spatial resolution in situ localization by detecting functional groups associated with cyanogenic glucosides using vibrational spectroscopy. Raman hyperspectral imaging revealed that dhurrin was found mainly surrounding epidermal, cortical and vascular tissue, with the greatest amount in cortical tissue. Numerous "hotspots" demonstrated dhurrin to be located within both cell walls and cytoplasm adpressed towards the plasmamembrane and not in the vacuole as previously reported. The high concentration of dhurrin in the outer cortical and epidermal cell layers is consistent with its role in defence against herbivory. This demonstrates the ability of Raman hyperspectral imaging to locate cyanogenic glucosides in intact tissues, avoiding possible perturbations and imprecision that may accompany methods that rely on bulk tissue extraction methods, such as protoplast isolation.
利用拉曼高光谱成像分析对高粱幼茎中代谢物的定位进行了研究，比较了野生型植物和缺乏氰苷葡萄糖的突变体。这种新方法通过检测与氰苷葡萄糖相关的功能基团，利用振动光谱实现了高空间分辨率的原位定位。拉曼高光谱成像显示，霍霍林主要存在于表皮、皮层和维管束组织周围，其中皮层组织中的含量最大。大量“热点”表明，霍霍林位于细胞壁和细胞质内，紧贴质膜，而不是以前报道的液泡中。霍霍林在外皮层和表皮细胞层中的高浓度与其在防御草食性方面的作用一致。这证明了拉曼高光谱成像能够在完整组织中定位氰苷葡萄糖，避免了可能伴随依赖于整体组织提取方法（如原生质体分离）的方法的潜在干扰和不准确性。
