Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
Chair of Plant Physiology and Biotechnology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland.
Int J Mol Sci. 2020 Mar 17;21(6):2042. doi: 10.3390/ijms21062042.
Plant senescence is a highly regulated process that allows nutrients to be mobilized from dying tissues to other organs. Despite that senescence has been extensively studied in leaves, the senescence of ephemeral organs located underground is still poorly understood, especially in the context of phytohormone engagement. The present study focused on filling this knowledge gap by examining the roles of abscisic acid (ABA) and jasmonate in the regulation of senescence of fine, absorptive roots and leaves of Immunohistochemical (IHC), chromatographic, and molecular methods were utilized to achieve this objective. A transcriptomic analysis identified significant changes in gene expression that were associated with the metabolism and signal transduction of phytohormones, especially ABA and jasmonate. The increased level of these phytohormones during senescence was detected in both organs and was confirmed by IHC. Based on the obtained data, we suggest that phytohormonal regulation of senescence in roots and leaves is organ-specific. We have shown that the regulation of ABA and JA metabolism is tightly regulated during senescence processes in both leaves and roots. The results were discussed with respect to the role of ABA in cold tolerance and the role of JA in resistance to pathogens.
植物衰老（senescence）是一个高度受调控的过程，该过程可以使养分从垂死的组织转移到其他器官。尽管衰老在叶片中已经得到了广泛的研究，但位于地下的短暂器官（ephemeral organs）的衰老仍然知之甚少，尤其是在植物激素参与的背景下。本研究通过研究脱落酸（ABA）和茉莉酸（jasmonate）在细根和叶片衰老中的调控作用，致力于填补这一知识空白。为了实现这一目标，采用了免疫组织化学（IHC）、色谱和分子方法。转录组分析确定了与植物激素代谢和信号转导相关的基因表达的显著变化，特别是 ABA 和茉莉酸。在这两个器官中都检测到衰老过程中这些植物激素水平的增加，并通过 IHC 得到了证实。基于获得的数据，我们提出植物激素对根和叶衰老的调控是器官特异性的。我们已经表明，ABA 和 JA 代谢的调控在叶片和根的衰老过程中受到严格调控。结果还讨论了 ABA 在耐冷性中的作用以及 JA 在抗病原体中的作用。
