The functional assay of OsNA R2.1 in rice

【作者】 范晓荣； 冯慧敏； 严明； 徐国华；

【机构】 南京农业大学资环学院；

【摘要】 <正>We report the physiological function of another member of the NAR2 family,OsNAR2.1 in rice(Oryza saliva,ssp.Japonica,cv.Nipponbare).OsNAR2.1 was mainly expressed in roots and induced by nitrate and suppressed by ammonium and some amino acids.Knockdown of OsNAR2.1 by RNA interference synchronously suppressed expression of OsNRT2.1,OsNRT2.2 and OsNRT2.3a in the osnar2.1mutants.Both high- and low-affinity nitrate transports were greatly impaired by OsNAR2.1 knockdown.Yeast two hybridization showed that OsNAR2.1 not only interacted with OsNRT2.1/OsNRT2.2,but also with OsNRT2.3a.The K_m value for nitrate uptake was 0.03 mM for OsNRT2.1/OsNRT2.2-OsNAR2.1 and 0.34 mM for OsNRT2.3a-OsNAR2.1 using the Xenopus oocyte heterologous expression system.Using promoter-GUS reporter plants and semi-quantitative RT-PCR analyses,we observed that OsNAR2.1 was expressed mainly in the root epidermal cells,A region from position -311 to -1,relative to the translation start site in the promoter region of OsNAR2.1,was found to contain the cis-element(s) necessary for the nitrate-, but not light- and sugar-dependent activation.Taken together,the data demonstrate that OsNAR2.1 plays a key role in enabling the plant to cope with variable nitrate supply.更多还原

【Abstract】 We report the physiological function of another member of the NAR2 family,OsNAR2.1 in rice(Oryza saliva,ssp.Japonica,cv.Nipponbare).OsNAR2.1 was mainly expressed in roots and induced by nitrate and suppressed by ammonium and some amino acids.Knockdown of OsNAR2.1 by RNA interference synchronously suppressed expression of OsNRT2.1,OsNRT2.2 and OsNRT2.3a in the osnar2.1mutants.Both high- and low-affinity nitrate transports were greatly impaired by OsNAR2.1 knockdown.Yeast two hybridization showed that OsNAR2.1 not only interacted with OsNRT2.1/OsNRT2.2,but also with OsNRT2.3a.The K_m value for nitrate uptake was 0.03 mM for OsNRT2.1/OsNRT2.2-OsNAR2.1 and 0.34 mM for OsNRT2.3a-OsNAR2.1 using the Xenopus oocyte heterologous expression system.Using promoter-GUS reporter plants and semi-quantitative RT-PCR analyses,we observed that OsNAR2.1 was expressed mainly in the root epidermal cells,A region from position -311 to -1,relative to the translation start site in the promoter region of OsNAR2.1,was found to contain the cis-element(s) necessary for the nitrate-, but not light- and sugar-dependent activation.Taken together,the data demonstrate that OsNAR2.1 plays a key role in enabling the plant to cope with variable nitrate supply.更多还原