Autophagy is an evolutionarily conserved mechanism that mediates the degradation of cytoplasmic components in eukaryotic cells. In plants, autophagy has been extensively associated with the recycling of proteins during carbon starvation conditions. Even tough lipids constitute a significant energy reserve, our understanding of the function of autophagy in the management of cell lipid reserves and components remains fragmented. To further investigate the significance of autophagy in lipid metabolism, we performed an extensive lipidomic characterization of Arabidopsis (Arabidopsis thaliana) autophagy mutants (atg) submitted to dark-induced senescence conditions. Our results revealed an altered lipid profile in atg mutants, suggesting that autophagy affects the homeostasis of multiple lipid components under dark-induced senescence. The acute degradation of chloroplast lipids coupled with the differential accumulation of triacylglycerols (TAGs) and plastoglobuli-related transcripts indicates an alternative metabolic reprogramming towards lipid storage in atg mutants. The imbalance of lipid metabolism compromises the production of cytosolic lipid droplets and the regulation of peroxisomal lipid oxidation pathways in atg mutants.

中文翻译：

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拟南芥在黑暗诱导衰老过程中脂质稳态需要自噬

自噬是一种进化保守的机制，介导真核细胞中细胞质成分的降解。在植物中，自噬与碳饥饿条件下蛋白质的循环利用广泛相关。即使坚韧的脂质构成了重要的能量储备，我们对自噬在细胞脂质储备和成分管理中的功能的理解仍然是零碎的。为了进一步研究自噬在脂质代谢中的重要性，我们对提交给黑暗诱导的衰老条件的拟南芥（Arabidopsis thaliana）自噬突变体（atg）进行了广泛的脂质组学表征。我们的研究结果揭示了atg突变体中脂质谱的改变，表明自噬会影响黑暗诱导的衰老下多种脂质成分的稳态。叶绿体脂质的急性降解，加上三酰基甘油（TAG）和质体相关转录物的差异积累，表明向atg突变体中的脂质存储提供了另一种代谢重编程方法。脂质代谢的不平衡损害了atg突变体中胞浆脂质小滴的产生和过氧化物酶体脂质氧化途径的调节。