Abstract: In order to explore the differentially expressed genes（DEGs）in Weike 518（WK518）with high nitrogen efficiency and Nongda108（ND108） with low nitrogen efficiency under nitrogen reduction condition and their functions，the ear⁃leaf samples were collected from WK518 and ND108 at mid filling stage under normal nitrogen fertilizer application rate（225 kg/ha nitrogen,HN）and low nitrogen fertilizer application rate（0 kg/hanitrogen,LN）,and used for high⁃throughput RNA sequencing. Then the GO term and KEGG metabolic pathway of DEGs were analyzed from different compared groups，and the differentially expressed transcription factor families were analyzed. The results showed that 2 065 up⁃regulated DEGs and 2 319 down⁃regulated DEGs were detected between WK518 and ND108 under LN condition,2 368 up⁃regulated DEGs and 3 780 down⁃regulated DEGs were detected under HN condition;1 009 up⁃regulated DEGs and 2 268 down⁃regulated DEGs were detected in WK518 under different nitrogen application rates,and 364 up⁃regulated DEGs and 510 down⁃regulated DEGs were detected in ND108 under different nitrogen application rates.Under LN condition,DEGs between WK518 and ND108 were mainly enriched in uroporphyrin⁃Ⅲ C⁃methyltransferase activity,mannose⁃6⁃phosphate isomerase activity,oxidation⁃reduction process,mitochondrion organization,nuclear chromatin and other GO terms,and amino sugar and nucleotide sugar metabolism,phenylalaninemetabolism,monoterpenoid biosynthesis,glycine/serine and threonine metabolism,base excision repair and other KEGG pathways. Under HN condition，DEGs between WK518 and ND108 were mainly enriched in stomatal closure,transmembrane receptor protein serine/threonine kinase activity,chloroplast stroma，thylakoid,chloroplast envelope and other GO terms,and carbon fixation in photosynthetic organisms，amino sugar and nucleotide sugar metabolism,glycolysis/gluconeogenesis,β⁃alanine metabolism,photosynthesis⁃antenna proteins and other KEGG pathways.DEGs in WK518 were mainly enriched in response to chitin,protein phosphorylation，membrane，indole glucosinolate metabolic process，galactinol⁃sucrose galactosyltransferase and other GO terms,and carbon fixation in photosynthetic origination,plant hormone signal transduction,protein processing in endoplasmic reticulum,plant⁃pathogen interaction,MAPK signaling pathway⁃plant and other KEGG pathways under different nitrogen application rates.DEGs in ND108 were mainly enriched in response to water deprivation,toxin catabolic process,chitinase activity,trehalose biosynthetic process,trehalose⁃phosphatase activity and other GO terms,and glyoxylate and dicarboxylate metabolism,MAPK signaling pathway⁃plant，prodigiosin biosynthesis,zeatin biosynthesis,biotin metabolism and other KEGG pathways under different nitrogen application rates.Fifty⁃eight differentially expressed transcription factor families were detected in WK518 and ND108 under different nitrogen application rates,including GRAS,bHLH,MYB⁃related,NAC,C3H,ERF,C2H2,WRKY,FAR1 transcription factor families and so on,which were very important in plants growth,development and response to biotic and abiotic stresses.

Key words: Maize, Nitrogen reduction, Nitrogen efficiency, High?throughput RNA sequencingDifferentially expressed gene（DEG）

摘要： 为了研究不同氮效率玉米品种伟科518（氮高效品种，WK518）、农大108（氮低效品种，ND108）在氮减施条件下的差异表达基因（Differently expressed genes，DEG）及其功能，在不同氮条件下［正常氮（225 kg/hm²，HN）、低氮（0 kg/hm²，LN）］，对灌浆中期WK518和ND108穗位叶进行高通量转录组测序，筛选DEG，进行GO和KEGG富集分析，并对差异表达的转录因子进行分析。结果表明，低氮条件下，在WK518与ND108对比组中共检测到2 065个上调表达基因、2 319个下调表达基因。正常氮条件下，在WK518与ND108对比组中共检测到2 368个上调表达基因、3 780个下调表达基因。WK518在不同氮条件下共检测到1 009个上调表达基因、2 268个下调表达基因。ND108在不同氮条件下共检测到364个上调表达基因、510个下调表达基因。低氮条件下，WK518与ND108中的DEG主要富集于尿卟啉−Ⅲ C−甲基转移酶活性、甘露糖−6−磷酸异构酶活性、氧化−还原过程、线粒体组织、核染色质等GO条目，氨基糖及核苷酸糖新陈代谢，苯丙氨酸新陈代谢，类单萜生物合成，甘氨酸、丝氨酸及苏氨酸新陈代谢、碱基剪切修复等KEGG代谢通路。正常氮条件下，WK518与ND108中的DEG主要富集于气孔关闭、跨膜受体丝氨酸/苏氨酸蛋白激酶活性、叶绿体基质、类囊体、叶绿体被膜等GO条目，光合作用生物体中碳固定、氨基糖及核苷酸糖新陈代谢、糖酵解/糖异生、丙氨酸新陈代谢、光合作用-天线蛋白等KEGG代谢通路。WK518在不同氮条件下的DEG主要富集于几丁质反应、蛋白质磷酸化、生物膜、吲哚硫代葡萄糖苷代谢过程、肌醇半乳糖苷-蔗糖半乳糖基转移酶等GO条目，光合作用生物体中碳固定、植物激素信号传导、内质网内蛋白质加工过程、植物-病原体相互作用、植物MAPK信号通路等KEGG代谢通路。ND108在不同氮条件下的DEG主要富集于干旱胁迫响应、毒素分解代谢过程、几丁质酶活性、海藻糖生物合成过程、海藻糖-磷酸酶活性等GO条目，乙醛酸及二羧酸盐新陈代谢、植物MAPK信号通路、灵菌素生物合成、玉米素生物合成、生物素新陈代谢等KEGG代谢通路。不同氮条件下，在WK518和ND108中共检测出58个差异表达转录因子家族，包括GRAS、bHLH、MYB相关、NAC、C3H、ERF、C2H2、WRKY、FAR1等植物中重要的调控生长发育、生物及非生物胁迫响应的转录因子家族。

关键词: 玉米, 氮肥减施, 氮效率, 高通量转录组测序, 差异表达基因