Geng Jie, Zhang Mei, Hu Jixun, Bilal Muhammad, Yang Jun, Hu Tao
State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, China.
BMC Plant Biol. 2025 Jul 2;25(1):819. doi: 10.1186/s12870-025-06817-y.
Nitrogen is one of the essential macronutrients bulk elements affecting plant growth and yield. However, the nitrogen content in most agricultural soils today is insufficient to meet the increasing demand for crop productivity. Festuca sinensis is an important cultivated forage grass found in high-altitude regions of China. Breeding forage varieties capable of maintaining high yields under nitrogen-deficient conditions is of great significance. Despite its ecological and agricultural importance, the molecular mechanisms underlying the response of Festuca sinensis to nitrogen starvation, as well as the identification of key regulatory genes, remain largely unexplored.
In this study, Festuca sinensis was cultured under different nitrogen concentrations using 1/2 Hoagland nutrient solution. Significant morphological differences were observed among the treatments, and physiological experiments confirmed that Festuca sinensis experienced substantial stress under low-nitrogen conditions. Subsequently, RNA-Seq analysis was conducted with four treatment groups and two plant tissue types. We focused on the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched with Differentially Expressed Genes (DEGs) in three aspects: (1) the nitrogen starvation response of Festuca sinensis, (2) the symbiosis between Festuca sinensis and Epichloë sinensis, and (3) the response to nitrogen starvation after symbiosis. Through this analysis, we screened five key genes (FsNRT2.2, FsNRT2.4, FsC/VIF2, FsIRT1, and FsYSL15) as potentially important regulators. Additionally, protein interaction network analysis revealed several core genes that may play crucial roles in nitrogen starvation response and provide insights for breeding new Festuca sinensis germplasm with enhanced nitrogen deficiency tolerance.
This study is the first to screen core genes in Festuca sinensis related to its response to nitrogen starvation, its symbiosis with Epichloë sinensis, and the symbiotic response to nitrogen-deficient conditions. the key genes identified along with their enriched pathways, provide valuable insights into the molecular mechanisms underlying nitrogen starvation tolerance. These genes can be utilized to develop new Epichloë sinensis germplasm with enhanced tolerance to nitrogen deficiency and may also serve as a reference for advancing nitrogen starvation research in other plant species.
氮是影响植物生长和产量的必需大量元素之一。然而，如今大多数农业土壤中的氮含量不足以满足对作物生产力日益增长的需求。中华羊茅是中国高海拔地区一种重要的栽培牧草。培育能够在缺氮条件下保持高产的牧草品种具有重要意义。尽管中华羊茅具有生态和农业重要性，但其对氮饥饿响应的分子机制以及关键调控基因的鉴定在很大程度上仍未得到探索。
在本研究中，使用1/2霍格兰营养液在不同氮浓度下培养中华羊茅。各处理间观察到显著的形态差异，生理实验证实中华羊茅在低氮条件下经历了严重胁迫。随后，对四个处理组和两种植物组织类型进行了RNA测序分析。我们从三个方面关注基因本体论（GO）术语和京都基因与基因组百科全书（KEGG）通路中差异表达基因（DEG）的富集情况：（1）中华羊茅的氮饥饿响应，（2）中华羊茅与中华内生真菌的共生关系，以及（3）共生后对氮饥饿的响应。通过该分析，我们筛选出五个关键基因（FsNRT2.2、FsNRT2.4、FsC/VIF2、FsIRT1和FsYSL15）作为潜在的重要调控因子。此外，蛋白质相互作用网络分析揭示了几个可能在氮饥饿响应中起关键作用的核心基因，并为培育具有更强耐缺氮能力的中华羊茅新种质提供了见解。
本研究首次在中华羊茅中筛选出与其对氮饥饿响应、与中华内生真菌共生以及对缺氮条件的共生响应相关的核心基因。所鉴定的关键基因及其富集的通路为耐氮饥饿的分子机制提供了有价值的见解。这些基因可用于培育对缺氮具有更强耐受性的中华羊茅新种质，也可为推进其他植物物种的氮饥饿研究提供参考。
