Li Xiaoliang, He Haitong, He Suqin, Wang Luyao, Zhang Wei, Kong Zhaosheng, Wang Lixiang
College of Agriculture, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
Shanxi HouJi Laboratory, Taiyuan 030031, Shanxi, China.
Sheng Wu Gong Cheng Xue Bao. 2025 Feb 25;41(2):657-669. doi: 10.13345/j.cjb.240407.
Peanut, a major economic and oil crop known for the high protein and oil content, is extensively cultivated in China. Peanut plants have the ability to form nodules with rhizobia, where the nitrogenase converts atmospheric nitrogen into ammonia nitrogen that can be utilized by the plants. Analysis of nodule fixation is of positive significance for avoiding overapplication of chemical fertilizer and developing sustainable agriculture. In this study, ., a member of the family predominantly expressed in peanut nodules, was identified by bioinformatics analysis. Subsequent spatiotemporal expression analysis revealed that . was highly expressed in nodules and showed significant responses to high nitrogen, low nitrogen, high phosphorus, low phosphorus, and rhizobia treatments. Histochemical staining indicated that the gene was primarily expressed in developing nodules and at the connection region between mature nodules and peanut roots. The fusion protein AhNIGT1.2-GFP was located in the nucleus of tobacco epidermal cells. The .-OE significantly increased the number of peanut nodules, while .-RNAi reduced the number of nodules, which suggested a positive regulatory role of AhNIGT1.2 in peanut nodulation. The .-OE in roots down-regulated the expression levels of ., ., , and , which indicated that . influenced peanut nodulation by modulating nitrate transport and the expression of genes. The transcriptome analysis of .-OE and control roots revealed that overexpressing . significantly enriched the differentially expressed genes associated with nitrate response, nodulation factor pathway, enzymes for triterpene biosynthesis, and carotenoid biosynthesis. These findings suggest that . play a key role in peanut nodulation by regulating nitrate transport and response and other related pathways. This study gives insights into the molecular mechanisms of nitrogen and phosphorus in regulating legume nodulation and nitrogen fixation, and sheds light on the development of legume crops that can efficiently fix nitrogen in high nitrogen environments.
花生是一种主要的经济作物和油料作物，以高蛋白和高含油量著称，在中国广泛种植。花生植株能够与根瘤菌形成根瘤，根瘤中的固氮酶将大气中的氮转化为氨态氮供植物利用。分析根瘤固氮对于避免过度施用化肥和发展可持续农业具有积极意义。在本研究中，通过生物信息学分析鉴定出了一个主要在花生根瘤中表达的 家族成员。随后的时空表达分析表明，该成员在根瘤中高度表达，并且对高氮、低氮、高磷、低磷和根瘤菌处理有显著响应。组织化学染色表明，该基因主要在发育中的根瘤以及成熟根瘤与花生根的连接区域表达。融合蛋白AhNIGT1.2-GFP定位于烟草表皮细胞的细胞核中。AhNIGT1.2过表达显著增加了花生根瘤的数量，而AhNIGT1.2-RNAi则减少了根瘤数量，这表明AhNIGT1.2在花生结瘤中起正调控作用。根中AhNIGT1.2过表达下调了 、 、 和 的表达水平，这表明AhNIGT1.2通过调节硝酸盐转运和 基因的表达影响花生结瘤。对AhNIGT1.2过表达和对照根的转录组分析表明，过表达AhNIGT1.2显著富集了与硝酸盐响应、结瘤因子途径、三萜生物合成酶和类胡萝卜素生物合成相关的差异表达基因。这些发现表明，AhNIGT1.2通过调节硝酸盐转运和响应以及其他相关途径在花生结瘤中起关键作用。本研究深入了解了氮和磷调控豆科植物结瘤和固氮的分子机制，并为在高氮环境下高效固氮的豆科作物的培育提供了思路。
