Jatropha curcas L. is an important biofuel plant with excellent tolerance of barren environments. However, studies on the regulatory mechanisms that operate in this plant in response to nitrogen (N) shortage are scarce. In this study, genome-wide transcriptional profiles of the roots and leaves of 8-week old physic nut seedlings were analyzed after 2 and 16 days of N starvation. Enrichment results showed that genes associated with N metabolism, processing and regulation of RNA, and transport predominated among those showing alterations in expression. Genes encoding transporter families underwent major changes in expression in both roots and leaves; in particular, those with roles in ammonia, amino acid and peptide transport were generally up-regulated after long-term starvation, while AQUAPORIN genes, whose products function in osmoregulation, were down-regulated. We also found that ASPARA−GINASE B1 and SARCOSINE OXIDASE genes were up-regulated in roots and leaves after 2 and 16 d N starvation. Genes associated with ubiquitination-mediated protein degradation were significantly up-regulated. In addition, genes in the JA biosynthesis pathway were strongly activated while expression of those in GA signaling was inhibited in leaves. We showed that four major classes of genes, those with roles in N uptake, N reutilization, C/N ratio balance, and cell structure and synthesis, were particularly influenced by long-term N limitation. Our discoveries may offer clues to the molecular mechanisms that regulate N reallocation and reutilization so as to maintain or increase plant performance even under adverse environmental conditions.
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机译:麻疯树是重要的生物燃料工厂,在贫瘠的环境中具有出色的耐受性。但是,缺乏针对该工厂响应氮(N)短缺而起作用的调节机制的研究。在这项研究中,在N饥饿2天和16天后,分析了8周龄物理坚果幼苗的根和叶的全基因组转录谱。富集结果显示,与N代谢,RNA加工和调控以及运输相关的基因在表达变化的基因中占主导。编码转运蛋白家族的基因在根和叶中的表达均发生了重大变化。特别是,那些长期处于饥饿状态的氨,氨基酸和肽转运中的氨基酸通常被上调,而其在渗透调节作用中起作用的AQUAPORIN基因则被下调。我们还发现,在2和16 d N饥饿后,根和叶中的ASPARA-GINASE B1和SARCOSINE OXIDASE基因被上调。与泛素介导的蛋白质降解相关的基因被显着上调。另外,JA生物合成途径中的基因被强烈激活,而GA信号传导中的那些基因的表达被抑制。我们显示出四个主要类别的基因,它们在氮吸收,氮再利用,C / N比平衡以及细胞结构和合成中起作用,特别受长期氮限制的影响。我们的发现可能为调节氮再分配和再利用的分子机制提供线索,从而即使在不利的环境条件下也能维持或提高植物的性能。
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