| 摘要: |
| 为探究不同氮素形态配比对马大相思(Acacia mangium × A. auriculiformis)无性系生长及基因表达的调控机制,以无性系组培苗AMA308为材料,在Hoagland营养液基础上设置5种NH5+/NO3-比例(0:10、3:7、5:5、7:3、10:0)处理,利用Illumina高通量测序平台进行转录组测序,通过edgeR筛选差异表达基因(DEGs)以|log2FC|>1且FDR<0.05为筛选标准,并进行KEGG富集分析,选取5个氮代谢基因进行RT-qPCR验证。结果表明:(1)随着营养液中硝态氮比例升高,根、叶差异表达基因数量显著增加,根部DEGs高于叶片。(2)根部DEGs显著富集于核糖体相关的通路(P<0.001),而叶片DEGs主要富集于代谢途径、次生代谢物生物合成及植物激素信号转导通路。(3)共鉴定出88个参与氮代谢的DEGs,涵盖硝酸转运、还原及谷氨酰胺合成等11个关键节点; 其中18个基因在根部随NO3-比例增加下调表达,13个上调; 叶片中13个下调、9个上调。(5)筛选到3个AMT1亚家族基因,它们均在根和叶中表达但根部表达量显著更高; 2个基因受铵离子诱导上调,而AMT1.1表达不受铵浓度影响,其在根部与叶片中的表达模式存在显著性差异。(5)RT-qPCR验证显示5个基因表达量与转录组数据相关系数≥0.79(P<0.05),证实了数据的可靠性。该研究揭示了马大相思根系和叶片协同响应氮素形态的分子基础,为其苗期精准施氮及分子育种提供了理论依据和候选基因。 |
| 关键词: 马大相思, 氮素形态, 转录组测序, 差异基因, 铵转运蛋白 |
| DOI：10.11931/guihaia.gxzw202509017 |
| 分类号:Q953 |
| 文章编号:1000-3152(2026)05-0862-15 |
| Fund project:国家自然科学基金(32271918)。 |
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| Effects of different nitrogen form ratios on growth and transcriptome response of Acacia mangium MA. auriculiformis seedlings |
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WANG Lihan1,2, WANG Xuyang1,3, XU Fang1, BAI Qingsong1,
LIAO Huanqin1, ZHANG Weihua1
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1. Guangdong Academy of Forestry, Guangzhou 510520, China;2. College of Forestry, Hebei Agricultural University,
Baoding 071001, Hebei, China;3. College of Agriculture, Yunnan University, Kunming 650091, China
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| Abstract: |
| In order to investigate the regulatory mechanisms underlying asexual growth and gene expression in Acacia mangium × A. auriculiformis clone AMA308 in response to different nitrogen form ratios, asexual tissue-cultured seedlings were used as materials, five different NH5+/NO3- ratios(0:10, 3:7, 5:5, 7:3, 10:0)were applied to Hoagland nutrient solution. After 30 days of hydroponic culture, transcriptome sequencing was performed on the Illumina platform, and differentially expressed genes(DEGs)were screened using edgeR with the criteria of |log2FC| > 1 and FDR < 0.05. KEGG enrichment analysis and quantitative real-time polymerase chain reaction(RT-qPCR)validation were conducted to verify the sequencing results. The results were as follows:(1)The number of DEGs in both root and leaf tissues increased significantly with the elevated proportion of nitrate in the nutrient solution, and root DEGs were consistently more abundant than leaf DEGs.(2)Root DEGs were significantly enriched in ribosome-related pathways(P<0.001), whereas leaf DEGs were predominantly enriched in metabolic pathways, secondary metabolite biosynthesis, and plant hormone signal transduction pathways.(3)A total of 88 DEGs were identified in nitrogen metabolism pathways, covering 11 key functional nodes including nitrate transport, nitrate reduction, and glutamine synthesis. Among these DEGs, 18 were down-regulated and 13 were up-regulated in roots with increasing NO3- ratio; in leaves, 13 were down-regulated and 9 were up-regulated.(5)Three genes belonging to the AMT1 subfamily were detected, which were expressed in both roots and leaves but showed significantly higher expression levels in roots. Two of these genes were ammonium-inducible and exhibited up-regulated expression with increasing NO3- ratio, while the expression of AMT1.1 was unaffected by external ammonium concentration and displayed distinct tissue-specific expression patterns between roots and leaves.(5)RT-qPCR validation demonstrated that the correlation coefficients between the expression levels of the four genes and the transcriptome data were ≥0.79(P<0.05)with the transcriptome sequencing data, confirming the high reliability of the RNA-Seq results. Collectively, this study demonstrates that Acacia mangium × A. auriculiformis modulates root and leaf responses to variable nitrogen forms via distinct molecular mechanisms. Ribosomal pathway enrichment in roots enhances protein synthesis capacity to facilitate efficient nitrogen uptake and assimilation, while enrichment of metabolic pathways in leaves optimizes nitrogen allocation to photosynthetic products and secondary metabolites, thereby supporting both photosynthetic performance and stress adaptation. This research elucidates the molecular basis of coordinated root-leaf responses to nitrogen forms for Acacia mangium × A. auriculiformis and provides theoretical support and candidate genes for precise nitrogen application during its seedling stage. |
| Key words: Acacia mangium × A. auriculiformis, nitrogen form, transcriptome sequencing, differentially expressed genes, ammonium transporter |
