Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.
Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, 701, Taiwan.
BMC Genomics. 2024 Jun 19;25(1):621. doi: 10.1186/s12864-024-10518-5.
Whole plant senescence represents the final stage in the life cycle of annual plants, characterized by the decomposition of aging organs and transfer of nutrients to seeds, thereby ensuring the survival of next generation. However, the transcriptomic profile of vegetative organs during this death process remains to be fully elucidated, especially regarding the distinctions between natural programmed death and artificial sudden death induced by herbicide.
Differential genes expression analysis using RNA-seq in leaves and roots of Arabidopsis thaliana revealed that natural senescence commenced in leaves at 45-52 days after planting, followed by roots initiated at 52-60 days. Additionally, both organs exhibited similarities with artificially induced senescence by glyphosate. Transcription factors Rap2.6L and WKRY75 appeared to serve as central mediators of regulatory changes during natural senescence, as indicated by co-expression networks. Furthermore, the upregulation of RRTF1, exclusively observed during natural death, suggested its role as a regulator of jasmonic acid and reactive oxygen species (ROS) responses, potentially triggering nitrogen recycling in leaves, such as the glutamate dehydrogenase (GDH) shunt. Root senescence was characterized by the activation of AMT2;1 and GLN1;3, facilitating ammonium availability for root-to-shoot translocation, likely under the regulation of PDF2.1.
Our study offers valuable insights into the transcriptomic interplay between phytohormones and ROS during whole plant senescence. We observed distinct regulatory networks governing nitrogen utilization in leaf and root senescence processes. Furthermore, the efficient allocation of energy from vegetative organs to seeds emerges as a critical determinant of population sustainability of annual Arabidopsis.
植物整体衰老代表了一年生植物生命周期的最后阶段，其特征是衰老器官的分解和营养物质向种子的转移，从而确保了下一代的生存。然而，在这个死亡过程中，营养器官的转录组图谱仍有待充分阐明，特别是关于自然程序性死亡和除草剂诱导的人工突然死亡之间的区别。
使用 RNA-seq 在拟南芥的叶片和根部进行差异基因表达分析表明，自然衰老从种植后 45-52 天开始在叶片中发生，随后在 52-60 天开始在根部发生。此外，这两个器官与草甘膦人工诱导的衰老表现出相似性。转录因子 Rap2.6L 和 WKRY75 似乎作为自然衰老过程中调节变化的中央介质，这表明它们在共表达网络中起作用。此外，仅在自然死亡过程中上调的 RRTF1 表明其作为茉莉酸和活性氧（ROS）反应调节剂的作用，可能触发叶片中的氮循环，如谷氨酸脱氢酶（GDH）旁路。根衰老的特征是 AMT2;1 和 GLN1;3 的激活，促进了铵在根部到地上部的转运中的可用性，这可能受 PDF2.1 的调节。
我们的研究为植物整体衰老过程中植物激素和 ROS 之间的转录组相互作用提供了有价值的见解。我们观察到了在叶片和根衰老过程中控制氮利用的不同调节网络。此外，从营养器官向种子有效分配能量是一年生拟南芥种群可持续性的关键决定因素。
