氮素是作物必需的營(yíng)養(yǎng)元素之一,，對(duì)作物的生命活動(dòng)和產(chǎn)量的形成具有重要意義。近年來(lái),，隨著農(nóng)田氮肥的過(guò)量施用,，對(duì)環(huán)境造成的污染也日益加重。提高作物氮利用效率,，是農(nóng)業(yè)可持續(xù)發(fā)展的關(guān)鍵,，是第二次“綠色革命”的目標(biāo)和要求。
中科院華南植物園植物營(yíng)養(yǎng)生理研究組博士研究生方中明在張明永研究員的指導(dǎo)下，發(fā)現(xiàn)在水稻中超表達(dá)OsPTR9基因可促進(jìn)水稻對(duì)銨態(tài)氮的吸收,，同時(shí)在低施氮肥的條件下可促進(jìn)水稻增產(chǎn),。研究顯示：OsPTR9基因的表達(dá)受外界氮源和光晝夜節(jié)律的調(diào)節(jié)。營(yíng)養(yǎng)生長(zhǎng)階段,，超表達(dá)OsPTR9能夠促進(jìn)銨的吸收,，增加側(cè)根的發(fā)生，提高水稻生物量,。生殖生長(zhǎng)階段,，超表達(dá)OsPTR9能夠提高氮再動(dòng)員和重新分配的運(yùn)輸效率，最終提高水稻產(chǎn)量,。在OsPTR9降低表達(dá)的突變體和RNAi植株中指標(biāo)和表型相反,。在不施氮肥的種植下，超標(biāo)達(dá)OsPTR9的水稻的產(chǎn)量比對(duì)照增幅最大,，達(dá)到18.6%,；正常施用氮肥下，超表達(dá)OsPTR9的水稻兩個(gè)株系比對(duì)照增產(chǎn)7.2%和8.1%,；施用銨態(tài)氮肥,，有利于超表達(dá)水稻獲得較高的產(chǎn)量。研究結(jié)果初步表明：OsPTR9在促進(jìn)氮利用效率和水稻分子育種上具有潛在的應(yīng)用價(jià)值,，該基因超表達(dá)后能夠提高土壤中氮的利用,，促進(jìn)水稻生長(zhǎng)并提高產(chǎn)量。
該研究成果已申請(qǐng)一項(xiàng)國(guó)家發(fā)明專利（專利號(hào)：201110022987.3）,，申請(qǐng)并公開(kāi)一項(xiàng)國(guó)際發(fā)明專利(專利號(hào)：PCT/CN2011/082100),。同時(shí)已在國(guó)際學(xué)術(shù)刊物Plant Biotechnology Journal(doi: 10.1111/pbi.12031，IF2011= 5.442)上發(fā)表,。(生物谷Bioon.com)
DOI: 10.1111/pbi.12031
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Altered expression of the PTR/NRT1 homologue OsPTR9 affects nitrogen utilization efficiency, growth and grain yield in rice
Zhongming Fang1,2,†, Kuaifei Xia1,3, Xin Yang1,2, Marianne Suter Grotemeyer4, Stefan Meier4, Doris Rentsch4, Xinlan Xu3, Mingyong Zhang1,3,*
The plant PTR/NRT1 (peptide transporter/nitrate transporter 1) gene family comprises di/tripeptide and low-affinity nitrate transporters; some members also recognize other substrates such as carboxylates, phytohormones (auxin and abscisic acid), or defence compounds (glucosinolates). Little is known about the members of this gene family in rice (Oryza sativa L.). Here, we report the influence of altered OsPTR9 expression on nitrogen utilization efficiency, growth, and grain yield. OsPTR9 expression is regulated by exogenous nitrogen and by the day-night cycle. Elevated expression of OsPTR9 in transgenic rice plants resulted in enhanced ammonium uptake, promotion of lateral root formation and increased grain yield. On the other hand, down-regulation of OsPTR9 in a T-DNA insertion line (osptr9) and in OsPTR9-RNAi rice plants had the opposite effect. These results suggest that OsPTR9 might hold potential for improving nitrogen utilization efficiency and grain yield in rice breeding.
