Wang Shenmeng, Wang Ruoning, Yang Chengjun
Northeast Asia Biodiversity Research Center, Northeast Forestry University, No. 26 Hexing Road, Xiangfang District, Harbin City, Heilongjiang Province, PR China.
School of Forestry, Northeast Forestry University, No. 26, Hexing Road, Harbin City, PR China.
Open Life Sci. 2022 Jul 13;17(1):756-780. doi: 10.1515/biol-2022-0084. eCollection 2022.
In plants, Dof transcription factors are involved in regulating the expression of a series of genes related to N uptake and utilization. Therefore, the present study investigated how DNA-binding with one finger (Dof) genes are expressed in response to nitrogen (N) form and concentration to clarify the role of Dof genes and their functions in promoting N assimilation and utilization in poplar. The basic characteristics and expression patterns of Dof genes in poplar were analyzed by the use of bioinformatics methods. Dof genes expressed in response to N were screened, after which the related genes were cloned and transformed into ; the physiological indexes and the expression of related genes were subsequently determined. The function of Dof genes was then verified in plants grown in the presence of different N forms and concentrations. Forty-four Dof genes were identified, most of which were expressed in the roots and young leaves, and some of the Dof genes were expressed under ammonia- and nitrate-N treatments. Three genes related to N induction were cloned, their proteins were found to localize in the nucleus, and was successfully transformed into for functional verification. On comparing with WT plants, plants overexpressing the Dof gene grew better under low N levels; the contents of soluble proteins and chlorophyll significantly increased, while the soluble sugar content significantly decreased. The expressions of several AMT, NRT, and GS genes were upregulated, while the expressions of several others were downregulated, and the expression of PEPC and PK genes significantly increased. In addition, the activity of PEPC, PK, GS, and NR enzymes significantly increased. The results showed that overexpression of significantly increased the level of carbon and N metabolism and improved the growth of transgenic plants under low-N conditions. The study revealed the biological significance of poplar Dof transcription factors in N response and regulation of related downstream gene expression and provided some meaningful clues to explain the huge difference between poplar and transformed by exogenous Dof gene, which could promote the comprehensive understanding of the molecular mechanism of efficient N uptake and utilization in trees.
在植物中，Dof转录因子参与调控一系列与氮素吸收和利用相关基因的表达。因此，本研究调查了单指DNA结合（Dof）基因如何响应氮形态和浓度表达，以阐明Dof基因在促进杨树氮同化和利用中的作用及其功能。利用生物信息学方法分析了杨树中Dof基因的基本特征和表达模式。筛选出响应氮素表达的Dof基因，随后克隆相关基因并转化到；测定了生理指标和相关基因的表达。然后在不同氮形态和浓度条件下生长的植物中验证Dof基因的功能。鉴定出44个Dof基因，其中大部分在根和幼叶中表达，一些Dof基因在氨态氮和硝态氮处理下表达。克隆了3个与氮诱导相关的基因，发现它们的蛋白质定位于细胞核，并成功转化到用于功能验证。与野生型植物相比，过表达Dof基因的植物在低氮水平下生长更好；可溶性蛋白质和叶绿素含量显著增加，而可溶性糖含量显著降低。几个AMT、NRT和GS基因的表达上调，而其他几个基因的表达下调，PEPC和PK基因的表达显著增加。此外，PEPC、PK、GS和NR酶的活性显著增加。结果表明，过表达显著提高了碳氮代谢水平，改善了转基因植物在低氮条件下的生长。该研究揭示了杨树Dof转录因子在氮响应和相关下游基因表达调控中的生物学意义，并为解释杨树与外源Dof基因转化的巨大差异提供了一些有意义的线索，有助于全面理解树木高效吸收和利用氮的分子机制。
