Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha 430128, China.
School of Agricultural Sciences, Zhengzhou University, Zhengzhou 475000, China.
Int J Mol Sci. 2020 Mar 21;21(6):2171. doi: 10.3390/ijms21062171.
Nitrogen (N) is essential for plant growth and crop productivity. Organic N is a major form of remobilized N in plants' response to N limitation. It is necessary to understand the regulatory role of N limitation adaption (NLA) in organic N remobilization for this adaptive response. Transcriptional and proteomic analyses were integrated to investigate differential responses of wild-type (WT) and mutant plants to N limitation and to identify the core organic N transporters targeted by NLA. Under N limitation, the mutant presented an early senescence with faster chlorophyll loss and less anthocyanin accumulation than the WT, and more N was transported out of the aging leaves in the form of amino acids. High-throughput transcriptomic and proteomic analyses revealed that N limitation repressed genes involved in photosynthesis and protein synthesis, and promoted proteolysis; these changes were higher in the mutant than in the WT. Both transcriptional and proteomic profiling demonstrated that LHT1, responsible for amino acid remobilization, were only significantly upregulated in the mutant under N limitation. These findings indicate that NLA might target LHT1 and regulate organic N remobilization, thereby improving our understanding of the regulatory role of NLA on N remobilization under N limitation.
氮（N）是植物生长和作物生产力的必需元素。有机氮是植物对氮限制响应中重新移动氮的主要形式。为了理解氮限制适应（NLA）在有机氮再移动中的调节作用，有必要了解这一适应性反应。本研究综合了转录组和蛋白质组分析，以研究野生型（WT）和突变体植物对氮限制的差异响应，并鉴定 NLA 靶向的核心有机氮转运体。在氮限制下，突变体表现出早期衰老，叶绿素损失更快，花青素积累更少，更多的氮以氨基酸的形式从衰老叶片中运输出去。高通量转录组和蛋白质组分析表明，氮限制抑制了参与光合作用和蛋白质合成的基因，并促进了蛋白水解；这些变化在突变体中比在 WT 中更高。转录组和蛋白质组分析均表明，LHT1 负责氨基酸再移动，仅在氮限制下突变体中显著上调。这些发现表明，NLA 可能靶向 LHT1 并调节有机氮再移动，从而提高我们对 NLA 在氮限制下调节氮再移动的作用的理解。
