Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
J Plant Physiol. 2021 Jan;256:153311. doi: 10.1016/j.jplph.2020.153311. Epub 2020 Nov 13.
The stress responses of plant compete for resources with growth and development. Resource allocations among these processes may have been optimized in plants adapted to natural habitats. Here, nitrogen (N) allocations were compared in leaves of Arabidopsis and Chorispora bungeana, a cryophyte with strong freezing tolerance. The results showed that the two species differed not only in N partitions among N forms and allocations among leaves, but also in their responses to cold stress. Interestingly, leaf protein contents were enhanced in C. bungeana while reduced in Arabidopsis, though the N allocations to leaves were reduced in both plants upon cold stress. Profoundly, when grown at warm temperature, contents of total free amino acids (FAAs) in leaves of C. bungeana were 6-11 times higher than those in Arabidopsis. In contrast, cold treatment induced FAAs accumulation in leaves of Arabidopsis without having significant effect in any leaf of C. bungeana. Considerable discrepancy was also found between the two species in the expressions of nitrate transporter genes and the activities of nitrate assimilation enzymes. Correlation and network analysis showed that most NPFs were clustered in a single network module and had loose relations with protein synthesis in Arabidopsis, while they were distributed in different modules in a decentralized network in C. bungeana. Therefore, our results reveal that C. bungeana may have optimized its N allocation strategy by producing and storing amino acids as efficient N reserve and adopting a decentralized network for N utilization, which may equip the plant with powerful capabilities for environmental adaptions.
植物的应激反应与生长和发育争夺资源。这些过程中的资源分配可能在适应自然栖息地的植物中得到了优化。在这里，我们比较了拟南芥和高山嵩草这两种植物的氮分配，高山嵩草是一种具有很强抗冻能力的低温植物。结果表明，这两个物种不仅在氮的分配方式、叶片的分配方式上存在差异，而且对冷胁迫的反应也不同。有趣的是，冷胁迫下，拟南芥叶片中的蛋白质含量降低，而高山嵩草中的蛋白质含量增加，尽管两种植物叶片中的氮分配都减少了。更有趣的是，当在温暖的温度下生长时，高山嵩草叶片中的总游离氨基酸（FAAs）含量是拟南芥的 6-11 倍。相比之下，冷处理诱导了拟南芥叶片中 FAAs 的积累，但对高山嵩草的任何叶片都没有显著影响。这两个物种在硝酸盐转运蛋白基因的表达和硝酸盐同化酶的活性方面也存在很大差异。相关性和网络分析表明，大多数 NPFs 在一个单独的网络模块中聚类，与拟南芥中的蛋白质合成关系松散，而在高山嵩草中则分布在不同的模块中，形成一个分散的网络。因此，我们的结果表明，高山嵩草可能通过产生和储存氨基酸作为有效的氮储备，并采用分散的氮利用网络来优化其氮分配策略，这可能使植物具备强大的环境适应能力。
