小麥氮磷高效與高產的協同機制研究

李燁　凌宏清

摘 要：氮、磷是限制植物生長發育的主重要營養素。在保證高產的前提下，提高小麥氮磷養分利用效率，是保障我國農業可持續發展、糧食和生態環境安全的必由之路。該研究通過對大量小麥品系進行在不同氮磷養分條件下的吸收利用效率分析，篩選出一批氮磷高效優異種質材料（品系），并利用對這些品系構建了一批近等基因系及F2代遺傳分析群體，對氮磷高效及產量性狀進行了系統的QTL分析。對氮同化關鍵谷氨酰胺合成酶基因GS的研究發現，TaGS2-A1與低氮條件下較高籽粒氮含量和千粒重相關聯，TaGS2-B1與低氮和高氮條件下的根系和地上部生物量相關聯；TaGS2-D1與低氮和高氮下的千粒重和小麥營養生長階段氮素吸收效率相關聯。通過缺失突變體研究發現，TaGS2-B缺失降低穗粒數和單株籽粒產量，進而降低單株籽粒氮含量。研究還發現磷高效位點Xgwm149-4B對千粒重具有重要影響；通過NF-Y家族成員及其上游基因tae-miR169的研究發現，tae-miR169調控了NF-YA不同成員對低氮和低磷響應的差異，超量表達TaNF-YA1-6B1可促進小麥的根系生長，有利于氮和磷高效吸收和提高小麥的穗數和籽粒產量。對94個小麥品系全基因組關聯分析，鑒定出在不同氮磷供應條件下與小麥千粒重、穗粒數和有效分蘗數顯著關聯的遺傳位點。利用含有矮稈基因的近等基因系在不同氮磷養分條件下的根系、氮磷吸收利用效率等方面的研究，發現矮桿基因對小麥的氮磷吸收存在一定的協同效應。通過構建好的遺傳群體及新挖掘的基因，為氮磷高效基因/QTL的定位和克隆，深入認識氮、磷高效吸收利用與高產性狀形成的協同機制奠定了基礎。

關鍵詞：小麥 氮 磷 養分高效吸收利用 全基因組關聯分析 養分與產量協同機制

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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