Page 131 - 《广西植物》2026年第5期
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5 期              王力涵等: 不同氮素形态配比对马大相思幼苗生长及转录组响应的分析                                           8 6 3

                 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 ratiosꎬ asexual tissue ̄cultured
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                 seedlings were used as materialsꎬ five different NH / NO  ratios (0 ∶ 10ꎬ 3 ∶ 7ꎬ 5 ∶ 5ꎬ 7 ∶ 3ꎬ 10 ∶ 0) were applied to
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                 Hoagland nutrient solution. After 30 days of hydroponic cultureꎬ transcriptome sequencing was performed on the Illumina
                 platformꎬ and differentially expressed genes (DEGs) were screened using edgeR with the criteria of |log FC | > 1 and
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                 FDR < 0.05. KEGG enrichment analysis and quantitative real ̄time PCR (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 solutionꎬ and root DEGs were consistently more
                 abundant than leaf DEGs. (2) Root DEGs were significantly enriched in ribosome ̄related pathways ( P< 0. 001)ꎬ
                 whereas leaf DEGs were predominantly enriched in metabolic pathwaysꎬ secondary metabolite biosynthesisꎬ and plant
                 hormone signal transduction pathways. (3) A total of 88 DEGs were identified in nitrogen metabolism pathwaysꎬ
                 covering 11 key functional nodes including nitrate transportꎬ nitrate reductionꎬ and glutamine synthesis. Among these
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                 DEGsꎬ 18 were down ̄regulated and 13 were up ̄regulated in roots with increasing NO  ratioꎻ in leavesꎬ 13 were down ̄
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                 regulated and 9 were up ̄regulated. (4) Three genes belonging to the AMT1 subfamily were detectedꎬ which were
                 expressed in both roots and leaves but showed significantly higher expression levels in roots. Two of these genes were
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                 ammonium ̄inducible and exhibited up ̄regulated expression with increasing NO  ratioꎬ while the expression of AMT1.1
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                 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 dataꎬ confirming the
                 high reliability of the RNA ̄Seq results. Collectivelyꎬ 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 assimilationꎬ while
                 enrichment of metabolic pathways in leaves optimizes nitrogen allocation to photosynthetic products and secondary
                 metabolitesꎬ 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. auriculiformisꎬ nitrogen formꎬ transcriptome sequencingꎬ differentially expressed
                 genes (DEGs)ꎬ ammonium transporter




                氮素是植物生长发育必需的大量营养元素ꎬ                            2020)ꎮ AMT 基因家族一般划分为 AMT1 和 AMT2
            作为蛋白质、核酸、叶绿素及多种代谢产物的核心                             两个亚家族ꎬ尽管两个亚家族成员之间结构高度
            组成成分ꎬ直接调控植物生长进程、产量形成与品                             相似ꎬ但其基因结构和成员数量均不同( 丛郁等ꎬ
                                                        -      2011)ꎮ 在基因结构上ꎬAMT1 家族成员一般不含
            质表现(李文鑫ꎬ 2020)ꎮ 土壤中的硝态氮(NO )
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            和铵态氮(NH ) 是植物获取氮素的主要形态ꎬ两                           内含子ꎬ多为高亲和转运体( Hao et al.ꎬ 2020)ꎻ
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            种形态氮素的转运代谢机制差异显著( Ge et al.ꎬ                       AMT2 家族成员含多个内含子且位置大小基本保
                                                               守ꎬ其亲和性无明确规律ꎻ在基因数量上ꎬAMT 家
            2025)ꎮ 硝态氮需经硝酸还原酶( nitrate reductaseꎬ
            NR)和亚硝酸还原酶( nitrite reductaseꎬ NIR) 催化             族成员一般为 6 ~ 16 个( Li et al.ꎬ 2021)ꎮ 在基因
            还原后才能被植物同化利用ꎬ而铵态氮可通过谷                              表达上ꎬ通过对水稻( Oryza sativa)、百脉根( Lotus
            氨酰胺合成酶( glutamine synthetaseꎬ GS) / 谷氨酸            corniculatus) 和白桦( Betula platyphylla) 的 研 究 发
            转运蛋白(glutamate transporter)途径直接参与代谢                现ꎬAMT 家族成员在根、茎和叶等的基因表达具有

            (王新磊和吕新芳ꎬ 2020)ꎮ                                   组织部位特异性(Simon ̄Rosin et al.ꎬ 2003)ꎮ 自拟
                 铵转运蛋白( ammonium transporterꎬ AMT) 是           南芥 AtAMT1.1 首次被克隆以来ꎬ模式植物中的
            植物吸收 NH 的关键元件ꎬ其介导的细胞铵离子                            AMT 家族的功能已得到系统解析ꎬ但木本植物基
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            的稳态维持对植物生理功能至关重要( Li et al.ꎬ                       因组测序起步较晚ꎬ固氮豆科木本植物的 AMT 家
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