小麥氮磷高效與高產(chǎn)的協(xié)同機(jī)制研究

李燁　凌宏清

摘 要：氮、磷是限制植物生長(zhǎng)發(fā)育的主重要營(yíng)養(yǎng)素。在保證高產(chǎn)的前提下，提高小麥氮磷養(yǎng)分利用效率，是保障我國(guó)農(nóng)業(yè)可持續(xù)發(fā)展、糧食和生態(tài)環(huán)境安全的必由之路。該研究通過(guò)對(duì)大量小麥品系進(jìn)行在不同氮磷養(yǎng)分條件下的吸收利用效率分析，篩選出一批氮磷高效優(yōu)異種質(zhì)材料（品系），并利用對(duì)這些品系構(gòu)建了一批近等基因系及F2代遺傳分析群體，對(duì)氮磷高效及產(chǎn)量性狀進(jìn)行了系統(tǒng)的QTL分析。對(duì)氮同化關(guān)鍵谷氨酰胺合成酶基因GS的研究發(fā)現(xiàn)，TaGS2-A1與低氮條件下較高籽粒氮含量和千粒重相關(guān)聯(lián)，TaGS2-B1與低氮和高氮條件下的根系和地上部生物量相關(guān)聯(lián)；TaGS2-D1與低氮和高氮下的千粒重和小麥營(yíng)養(yǎng)生長(zhǎng)階段氮素吸收效率相關(guān)聯(lián)。通過(guò)缺失突變體研究發(fā)現(xiàn)，TaGS2-B缺失降低穗粒數(shù)和單株籽粒產(chǎn)量，進(jìn)而降低單株籽粒氮含量。研究還發(fā)現(xiàn)磷高效位點(diǎn)Xgwm149-4B對(duì)千粒重具有重要影響；通過(guò)NF-Y家族成員及其上游基因tae-miR169的研究發(fā)現(xiàn)，tae-miR169調(diào)控了NF-YA不同成員對(duì)低氮和低磷響應(yīng)的差異，超量表達(dá)TaNF-YA1-6B1可促進(jìn)小麥的根系生長(zhǎng)，有利于氮和磷高效吸收和提高小麥的穗數(shù)和籽粒產(chǎn)量。對(duì)94個(gè)小麥品系全基因組關(guān)聯(lián)分析，鑒定出在不同氮磷供應(yīng)條件下與小麥千粒重、穗粒數(shù)和有效分蘗數(shù)顯著關(guān)聯(lián)的遺傳位點(diǎn)。利用含有矮稈基因的近等基因系在不同氮磷養(yǎng)分條件下的根系、氮磷吸收利用效率等方面的研究，發(fā)現(xiàn)矮桿基因?qū)π←湹牡孜沾嬖谝欢ǖ膮f(xié)同效應(yīng)。通過(guò)構(gòu)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(rèn)識(shí)氮、磷高效吸收利用與高產(chǎn)性狀形成的協(xié)同機(jī)制奠定了基礎(chǔ)。

關(guān)鍵詞：小麥 氮 磷 養(yǎng)分高效吸收利用 全基因組關(guān)聯(lián)分析 養(yǎng)分與產(chǎn)量協(xié)同機(jī)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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