Žnidarič Magda Tušek, Zagorščak Maja, Ramšak Živa, Stare Katja, Chersicola Marko, Novak Maruša Pompe, Kladnik Aleš, Dermastia Marina
Department of Biotechnology and Systems Biology National Institute of Biology Ljubljana Slovenia.
School of Viticulture and Enology University of Nova Gorica Vipava Slovenia.
Plant Direct. 2025 Jan 8;9(1):e70035. doi: 10.1002/pld3.70035. eCollection 2025 Jan.
Abscission is a tightly regulated process in which plants shed unnecessary, infected, damaged, or aging organs, as well as ripe fruits, through predetermined abscission zones in response to developmental, hormonal, and environmental signals. Despite its importance, the underlying mechanisms remain incompletely understood. This study highlights the deleterious effects of abscission on chloroplast ultrastructure in the cells of the tomato flower pedicel abscission zone, revealing spatiotemporal differential gene expression and key transcriptional networks involved in chloroplast vesiculation during abscission. Significant changes in chloroplast structure and vesicle formation were observed 8 and 14 h after abscission induction, coinciding with the differential expression of vesiculation-related genes, particularly with upregulation of () and (). This suggests a possible vesicle transport of chloroplast degrading material for recycling by autophagy-independent senescence-associated vacuoles (SAVs) and CV-containing vesicles (CCVs). Ethylene signaling appears to be involved in the regulation of these processes, as treatment with a competitive inhibitor of ethylene action, 1-methylcyclopropene, delayed vesiculation, reduced the expression of , and increased expression of (). In addition, chloroplast vesiculation during abscission was associated with differential expression of photosynthesis-related genes, particularly those involved in light reactions, underscoring the possible functional impact of the observed structural changes. This work provides new insights into the molecular and ultrastructural mechanisms underlying abscission and offers potential new targets for agricultural or biotechnological applications.
脱落是一个受到严格调控的过程，在此过程中，植物会通过预先确定的脱落区，响应发育、激素和环境信号，脱落不必要的、受感染的、受损的或衰老的器官以及成熟果实。尽管其很重要，但其潜在机制仍未完全了解。本研究突出了脱落对番茄花柄脱落区细胞中叶绿体超微结构的有害影响，揭示了脱落过程中叶绿体囊泡化所涉及的时空差异基因表达和关键转录网络。在脱落诱导后8小时和14小时观察到叶绿体结构和囊泡形成的显著变化，这与囊泡化相关基因的差异表达一致，特别是（）和（）的上调。这表明叶绿体降解物质可能通过不依赖自噬的衰老相关液泡（SAVs）和含CV的囊泡（CCVs）进行囊泡运输以进行回收利用。乙烯信号似乎参与了这些过程的调控，因为用乙烯作用的竞争性抑制剂1-甲基环丙烯处理会延迟囊泡化，降低（）的表达，并增加（）的表达。此外，脱落过程中的叶绿体囊泡化与光合作用相关基因的差异表达有关，特别是那些参与光反应的基因，这突出了所观察到的结构变化可能产生的功能影响。这项工作为脱落的分子和超微结构机制提供了新的见解，并为农业或生物技术应用提供了潜在的新靶点。
