Plants are continuously exposed to different abiotic and biotic stresses; therefore, to protect themselves, they depend on the fast reprogramming of large gene repertoires to prioritize the expression of a given stress-induced gene set over normal cellular household genes. The activity of the proteasome, a large proteolytic complex that degrades proteins, is vital to coordinate the expression of such genes. Proteins are labeled for degradation by the action of E3 ligases that site-specifically alter their substrates by adding chains of ubiquitin. Recent publications have revealed an extensive role of ubiquitination in the utilization of nutrients. This study presents the transcriptomic profiles of sulfur-deficient rosettes and roots of Arabidopsis thaliana rpt2a mutant with proteasomal malfunction. We found that genes connected with sulfur metabolism are regulated to the lesser extent in rpt2a mutant while genes encoding transfer RNAs and small nucleolar RNAs are highly upregulated. Several genes encoding E3 ligases are specifically regulated by sulfur deficiency. Furthermore, we show that a key transcription factor of sulfur deficiency response, Sulfur LIMitation1, undergoes proteasomal degradation and is able to interact with F-box protein, EBF1.

中文翻译：

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蛋白质的蛋白酶体降解对于植物对硫缺乏条件的正确转录反应很重要。

植物不断暴露于不同的非生物和生物胁迫下。因此，为了保护自己，他们依靠大型基因库的快速重编程来优先处理特定应激诱导基因组的表达，而不是正常细胞家庭基因。蛋白酶体（一种降解蛋白的大型蛋白水解复合物）的活性对于协调此类基因的表达至关重要。蛋白质通过E3连接酶的作用被标记为降解，该酶通过添加泛素链位点特异性地改变其底物。最近的出版物揭示了泛素化在营养利用中的广泛作用。这项研究提出了缺硫的莲座丛和拟南芥rpt2a根的转录组谱蛋白酶体功能异常的突变体。我们发现与硫代谢相关的基因在rpt2a突变体中受到的调控较小，而编码转移RNA和小核仁RNA的基因则被高度上调。几种编码E3连接酶的基因受硫缺乏的特异性调控。此外，我们表明硫缺乏反应的关键转录因子，Sulfur LIMitation1，经历了蛋白酶体降解，并能够与F-box蛋白EBF1相互作用。