Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Elche, Spain.
CEBAS-CSIC, Department of Plant Nutrition, Campus Universitario de Espinardo, 30100 Murcia, Spain.
Int J Mol Sci. 2021 Oct 31;22(21):11843. doi: 10.3390/ijms222111843.
Plants have a remarkable regenerative capacity, which allows them to survive tissue damage after biotic and abiotic stresses. In this study, we use 'Micro-Tom' explants as a model to investigate wound-induced de novo organ formation, as these explants can regenerate the missing structures without the exogenous application of plant hormones. Here, we performed simultaneous targeted profiling of 22 phytohormone-related metabolites during de novo organ formation and found that endogenous hormone levels dynamically changed after root and shoot excision, according to region-specific patterns. Our results indicate that a defined temporal window of high auxin-to-cytokinin accumulation in the basal region of the explants was required for adventitious root formation and that was dependent on a concerted regulation of polar auxin transport through the hypocotyl, of local induction of auxin biosynthesis, and of local inhibition of auxin degradation. In the apical region, though, a minimum of auxin-to-cytokinin ratio is established shortly after wounding both by decreasing active auxin levels and by draining auxin via its basipetal transport and internalization. Cross-validation with transcriptomic data highlighted the main hormonal gradients involved in wound-induced de novo organ formation in tomato hypocotyl explants.
植物具有显著的再生能力，这使它们能够在生物和非生物胁迫后存活下来，并修复组织损伤。在这项研究中，我们使用“Micro-Tom”外植体作为模型，研究创伤诱导的新器官形成，因为这些外植体可以在不添加外源植物激素的情况下再生缺失的结构。在这里，我们在新器官形成过程中同时对 22 种与植物激素相关的代谢物进行了靶向分析，发现内源激素水平在根和芽切除后根据区域特异性模式动态变化。我们的结果表明，外植体基部高生长素/细胞分裂素积累的特定时间窗口是不定根形成所必需的，这依赖于通过下胚轴协调调节极性生长素运输、局部诱导生长素生物合成以及局部抑制生长素降解。然而，在顶端区域，在受伤后不久，通过降低活性生长素水平和通过其向基运输和内化消耗生长素，建立了一个最低的生长素/细胞分裂素比值。与转录组数据的交叉验证突出了番茄下胚轴外植体中创伤诱导新器官形成所涉及的主要激素梯度。
