小麦氮磷高效与高产的协同机制研究

李烨　凌宏清

摘 要：氮、磷是限制植物生长发育的主重要营养素。在保证高产的前提下，提高小麦氮磷养分利用效率，是保障我国农业可持续发展、粮食和生态环境安全的必由之路。该研究通过对大量小麦品系进行在不同氮磷养分条件下的吸收利用效率分析，筛选出一批氮磷高效优异种质材料（品系），并利用对这些品系构建了一批近等基因系及F2代遗传分析群体，对氮磷高效及产量性状进行了系统的QTL分析。对氮同化关键谷氨酰胺合成酶基因GS的研究发现，TaGS2-A1与低氮条件下较高籽粒氮含量和千粒重相关联，TaGS2-B1与低氮和高氮条件下的根系和地上部生物量相关联；TaGS2-D1与低氮和高氮下的千粒重和小麦营养生长阶段氮素吸收效率相关联。通过缺失突变体研究发现，TaGS2-B缺失降低穗粒数和单株籽粒产量，进而降低单株籽粒氮含量。研究还发现磷高效位点Xgwm149-4B对千粒重具有重要影响；通过NF-Y家族成员及其上游基因tae-miR169的研究发现，tae-miR169调控了NF-YA不同成员对低氮和低磷响应的差异，超量表达TaNF-YA1-6B1可促进小麦的根系生长，有利于氮和磷高效吸收和提高小麦的穗数和籽粒产量。对94个小麦品系全基因组关联分析，鉴定出在不同氮磷供应条件下与小麦千粒重、穗粒数和有效分蘖数显著关联的遗传位点。利用含有矮秆基因的近等基因系在不同氮磷养分条件下的根系、氮磷吸收利用效率等方面的研究，发现矮杆基因对小麦的氮磷吸收存在一定的协同效应。通过构建好的遗传群体及新挖掘的基因，为氮磷高效基因/QTL的定位和克隆，深入认识氮、磷高效吸收利用与高产性状形成的协同机制奠定了基础。

关键词：小麦 氮 磷 养分高效吸收利用 全基因组关联分析 养分与产量协同机制

Abstract：Nitrogen （N） and phosphate （P） are important nutrients limited plant growth. Elevating nutrient using efficiency to reduce fertilization in food production is an urgently great requirement for protection of environment， green agriculture and sustainable development of national economics. In this study， we screened wheat germplasms and selected varieties with high N and P using efficiency， generated some isogenic lines and F2 populations using them， and analyzed QTLs for high N/P using efficiency and high yield. We found that TaGS2-A1 was related to N content of seeds and thousand grain weight （TGW） under low N conditions， TaGS2-B1 was correlated with root and shoot weight under low and high N conditions， and TaGS2-D1 was related to TGW and N absorption efficiency of vegetative growth of wheat under low and high N conditions. By analyzing deletion mutant， we found that deletion of TaGS2-B reduced seed number per ear， yield per plant and seed N content per plant. We also found Xgwm149-4B， a high P-efficiency locus， had important effect on TGW. By studying NF-Y gene family and their upstream gene tae-miR169， we found tae-miR169 regulated the expression of NF-YA members under low N/P conditions， Overexpression of TaNF-YA1-6B1 could enhanced wheat root growth， high N/P absorption， spike and seed number. Using whole genome association analysis using 94 wheat varieties， we detected the genetic loci related to TGW， spike number and productive tilling number under different N/P conditions. Further， we characterizated the effects of wheat dwarf genes （Rhts） on root development， N/P absorption and utilization efficiency under different N/P conditions， and found the different Rht genes had different effect on wheat N and P absorption and root development. The results obtained in this study provide a good basis for further mapping and cloning genes/QTLs for high N/P efficiency， and analyzing their synergistic effects on absorption， translocation， utilization efficiency of N and P， and as well as high yield.

Key Words：Wheat； Nitrogen； Phosphate； Effective absorption and utilization of nutrients； Whole genome association analysis； Synergistic mechanisms of nutrients and yield

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