Dhurrin is the most abundant cyanogenic glucoside found in sorghum (Sorghum bicolor) where it plays a key role in chemical defense by releasing toxic hydrogen cyanide upon tissue disruption. Besides this well-established function, there is strong evidence that dhurrin plays additional roles, e.g. as a transport and storage form of nitrogen, released via endogenous recycling pathways. However, knowledge about how, when and why dhurrin is endogenously metabolized is limited. We combined targeted metabolite profiling with matrix-assisted laser desorption/ionization-mass spectrometry imaging to investigate accumulation of dhurrin, its recycling products and key general metabolites in four different sorghum lines during 72 h of grain imbibition, germination and early seedling development, as well as the spatial distribution of these metabolites in two of the lines. Little or no dhurrin or recycling products were present in the dry grain, but their de novo biosynthesis started immediately after water uptake. Dhurrin accumulation increased rapidly within the first 24 h in parallel with an increase in free amino acids, a key event in seed germination. The trajectories and final concentrations of dhurrin, the recycling products and free amino acids reached within the experimental period were dependent on genotype. Matrix-assisted laser desorption/ionization-mass spectrometry imaging demonstrated that dhurrin primarily accumulated in the germinating embryo, confirming its function in protecting the emerging tissue against herbivory. The dhurrin recycling products, however, were mainly located in the scutellum and/or pericarp/seed coat region, suggesting unknown key functions in germination.

Dhurrin是高粱中发现的最丰富的氰甙（高粱）通过在组织破裂时释放有毒的氰化氢，在化学防御中发挥关键作用。除了这种公认的功能外，有充分的证据表明，杜兰精还具有其他作用，例如通过内源性循环途径释放的氮的运输和储存形式。但是，关于如何，何时以及为什么对杜林内源性代谢的知识是有限的。我们将目标代谢物谱图与基质辅助激光解吸/电离质谱光谱成像相结合，研究了谷物吸收，发芽和幼苗早期生长72小时内，四种蛋白质在高粱中的Durrin，其再循环产物和主要一般代谢物的积累情况。这些代谢物在两条线中的空间分布。干燥谷粒中几乎没有杜林或回收产物，但吸水后立即开始从头进行生物合成。在最初的24小时内，Durrin积累迅速增加，与此同时，游离氨基酸的增加是种子发芽的关键事件。在实验期间达到的杜林蛋白的轨迹和最终浓度，再循环产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。但吸水后立即开始从头开始生物合成。在最初的24小时内，Durrin积累迅速增加，与此同时，游离氨基酸的增加是种子发芽的关键事件。在实验期间达到的杜林蛋白的轨迹和最终浓度，再循环产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。但吸水后立即开始从头开始生物合成。在最初的24小时内，Durrin积累迅速增加，与此同时，游离氨基酸的增加是种子发芽的关键事件。在实验期内达到的杜林蛋白的轨迹和最终浓度，回收产物和游离氨基酸均取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。在最初的24小时内，Durrin积累迅速增加，与此同时，游离氨基酸的增加是种子发芽的关键事件。在实验期间达到的杜林蛋白的轨迹和最终浓度，再循环产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。在最初的24小时内，Durrin积累迅速增加，与此同时，游离氨基酸的增加是种子发芽的关键事件。在实验期间达到的杜林蛋白的轨迹和最终浓度，再循环产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。在实验期内达到的回收产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。在实验期内达到的回收产物和游离氨基酸取决于基因型。基质辅助激光解吸/电离质谱光谱成像表明，杜尔林主要积累在发芽的胚胎中，证实了其在保护新兴组织免受草食动物方面的功能。然而，Durrin回收产品主要位于盾片和/或果皮/种皮区域，这表明其发芽的关键功能未知。