不同氮利用效率小麦品种TaNRT/TaNPF家族基因表达特点

Gene expression characteristics of TaNRT/TaNPF family in wheat cultivars with different nitrogen efficiency

氮素是小麦生长发育的必需元素之一,NO_(3)^(-)-N是小麦从土壤中获取氮的主要形式。NRT/NPF家族基因编码膜转运蛋白,主要参与植物NO_(3)^(-)-N吸收、运输及分配。为了解小麦NRT/NPF家族基因与氮素利用的关系,选用氮高效小麦品种周麦27(ZM27)和氮低效品种矮抗58(AK58),利用二代测序技术,研究了不同氮水平(N120、N225、N330)开花期TaNRT/TaNPF家族基因在旗叶中的表达特点。结果表明,二代测序鉴定到386个TaNRT/TaNPF家族基因;与AK58相比,ZM27在氮减量(N120)、正常(N225)、过量(N330)条件下差异表达基因分别为27、16和23个,上调表达基因分别为16(59.26%)、12(75%)和19(82.61%)个;减氮条件下ZM27有7个特异下调表达基因,氮过量条件下TaNPF8.1表达量最高,且显著上调1.5倍。可见,TaNRT/TaNPF家族基因表达水平受施氮量及品种调控。利用小麦网络数据库分析发现TaNRT/TaNPF家族基因表达具有组织特异性及染色体偏好性,旗叶表达量最高的TaNPF8.1定位于3A染色体,根系特异表达的TaNRT2.2和TaNRT3.1主要分布于6号染色体,茎秆特异表达的TaNPF4.5主要分布在2号染色体。qRT-PCR分析显示TaNRT/TaNPF基因表达特点与二代转录组及网络数据结果一致。TaNPF8.1、TaNPF4.5和TaNRT3.1蛋白互作分析发现,NO_(3)^(-)-N转运可能还需要转录因子MYB、叶绿素A-B结合蛋白、伴侣蛋白等协同参与,为进一步研究TaNRT/TaNPF家族表达与氮素吸收利用的关系奠定了基础。

Nitrogen is one of the essential elements for wheat growth and development,and NO_(3)^(-)-N is the main form of nitrogen that wheat obtains from soil.NRT/NPF genes family encode membrane transporters,which are mainly involved in NO_(3)^(-)-N absorption,transport,and allocation in plants.In order to understand the relationship between NRT/NPF family and nitrogen utilization in wheat,the relative expression characteristic of TaNRT/TaNPF family in flag leaves of N-efficient wheat cultivars Zhoumai 27(ZM27)and N-inefficient wheat cultivars Aikang 58(AK58)at flowering stage were studied with the second-generation sequencing technology.The results showed that 386 genes of TaNRT/TaNPF family were identified in the second generation transcriptome database.Compared with AK58,there were 27,16,and 23 differentially expressed genes in ZM27 in reducing(N120),normal(N225),and excessive(N330)nitrogen treatments.There were 16(59.26%),12(75%),and 19(82.61%)up-regulated genes in ZM27,respectively.Seven genes were down-regulated in ZM27 in reducing nitrogen treatment.The relative expression level of TaNPF8.1 was the highest and significantly up-regulated by 1.5 times in nitrogen excessive condition.In conclusion,the relative expression of TaNRT/TaNPF family genes was regulated by nitrogen application rate and cultivar.Wheat network data base showed that the relative expression of TaNRT/TaNPF family had tissue specificity and chromosomal preference.The highest expression level of TaNPF8.1 in flag leaf was located on chromosome 3A,and the root specific expression TaNRT2.2 and TaNRT3.1 were mainly distributed on chromosome 6.The stem specific expression of TaNPF4.5 was mainly distributed on chromosome 2.The qRT-PCR of TaNRT/TaNPF genes were consistent with the results of the second-generation transcriptome and network data.Interaction analysis of TaNPF8.1,TaNPF4.5,and TaNRT3.1 revealed that NO3--N transport may also require the collaborative participation of transcription factor MYB,chlorophyll A-B binding protein,and chaperone protein.These findings laid a foundation for further studies on the relationship between TaNRT/TaNPF family expression and nitrogen uptake and utilization.