Zhu Lingxiao, Liu Liantao, Sun Hongchun, Zhang Yongjiang, Zhu Jijie, Zhang Ke, Li Anchang, Bai Zhiying, Wang Guiyan, Li Cundong
State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Crop Growth Regulation of Hebei Province, College of Agronomy, Hebei Agricultural University, Baoding, China.
Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Science, Shijiazhuang, China.
Front Plant Sci. 2021 Oct 18;12:748715. doi: 10.3389/fpls.2021.748715. eCollection 2021.
Nitrogen (N) deficiency is one of the pivotal environmental factors that induce leaf senescence. However, little is known regarding the impact of low N on root senescence in cotton. Thus, the objective of this study was to investigate the effect of low nitrogen on root senescence. In this study, the molecular mechanism of cotton root senescence in response to nitrogen deficiency was investigated by combing physiological and transcriptomic analysis when no nitrogen and normal nitrogen (138mg N·kg soil). The results showed that: (1) nitrogen starvation induced the premature senescence of leaf, while delaying root senescence. (2) The increase in catalase (CAT) activity at 60, 80, and 100days after emergence (DAE), combined with decrease of malonaldehyde content at 60, 80, and 100 DAE, and the content of abscisic acid (ABA), all of these contributed to the delay of root senescence by low nitrogen treatment. (3) To study the molecular mechanisms underlying root senescence, the gene expression profiling between low nitrogen and normal nitrogen treatments were compared pairwise at 20, 40, 60, 80, and 100 DAE. A total of 14,607 genes were identified to be differentially expressed at these five points. (5) Most genes involved in glutathione (GSH) and ascorbate peroxidase (APX) synthesis were upregulated, while ABA, apoptosis, caspase, and cell cycle-related differentially expressed genes (DEGs) were downregulated. Coupled with the physiology data, these results provide new insights into the effect of nitrogen starvation on root senescence.
氮（N）缺乏是诱导叶片衰老的关键环境因素之一。然而，关于低氮对棉花根系衰老的影响知之甚少。因此，本研究的目的是探究低氮对根系衰老的影响。在本研究中，通过在无氮和正常氮（138mg N·kg土壤）条件下结合生理和转录组分析，研究了棉花根系衰老对缺氮响应的分子机制。结果表明：（1）氮饥饿诱导叶片过早衰老，同时延缓根系衰老。（2）出苗后60、80和100天过氧化氢酶（CAT）活性增加，同时60、80和100天丙二醛含量降低，以及脱落酸（ABA）含量，所有这些都有助于低氮处理延缓根系衰老。（3）为了研究根系衰老的分子机制，在出苗后20、40、60、80和100天对低氮和正常氮处理之间的基因表达谱进行了两两比较。在这五个时间点共鉴定出14607个差异表达基因。（5）大多数参与谷胱甘肽（GSH）和抗坏血酸过氧化物酶（APX）合成的基因上调，而ABA、凋亡、半胱天冬酶和细胞周期相关的差异表达基因（DEGs）下调。结合生理数据，这些结果为氮饥饿对根系衰老的影响提供了新的见解。
