中文摘要：

【目的】生长素响应因子（ARF）在介导生长素信号传递和调控下游生长素响应基因的表达中发挥着重要功能。本文旨在以在富集丰磷特异表达基因的小麦根系c DNA差减文库中鉴定的1个ARF类别的家族成员TaARF6为基础,对该基因c DNA序列、分子特征、不同供磷水平下该基因在根、叶中表达模式及遗传转化TaARF6对丰磷和缺磷条件下植株形态的影响进行较全面研究,阐明该小麦生长素响应因子基因介导不同供磷水平下对植株生长特性的影响。【方法】采用生物信息学工具预测TaARF6编码蛋白特征;采用溶液培养法培养丰、缺磷处理小麦幼苗,采用半定量RT-PCR技术鉴定TaARF6在丰、缺磷处理下的表达特征。采用DNA重组技术构建将TaARF6编码阅读框融合至表达载体中的表达质粒,利用农杆菌介导的遗传转化法建立超表达TaARF6转基因烟草植株。采用琼脂培养和溶液培养法,培养丰、缺磷不同供磷水平下野生型植株和转基因烟草植株,进而利用常规分析方法鉴定不同磷水平下植株长势、根系和茎叶生物量和植株根叶形态及性状。【结果】1）TaARF6编码生长素响应因子（ARF）型转录因子,编码蛋白中含有ARF家族成员具有的保守结构域。该基因在氨基酸水平上与源于短柄草Bd ARF6和源于水稻的Os ARF6具有高度同源特征。表达分析表明,TaARF6在根、叶中均呈典型低磷下表达下调、复磷后表达再度回升模式,表明该基因表达受到外界供磷水平的调节。2）遗传转化结果表明,在正常生长和低磷逆境下,与野生型植株相比,转基因烟草株系幼苗和植株形态明显增大。3）丰、缺磷不同供磷水平下,与未转化的野生型（WT）对照植株相比,转基因系（Line 3和Line 5）植株幼苗和植株根系、茎叶和单株鲜、干重均较野生型显著增加。此外,与WT相比,转基因系植株根系数量增多、主侧根长度、根体积?

英文摘要：

【Objectives】Auxin response factors（ ARFs） play a critical role in mediating transduction of auxin signaling and regulating expression of downstream auxin-responsive genes. In this study,an ARF type transcription factor gene referred to TaARF6 identified in a root suppression subtractive c DNA library that enriches the differentially expressed genes under Pi sufficiency as the basis was used to investigate molecular characterization of TaARF6 and its expression patterns under various Pi-supply conditions,as well as its functions in regulating plant phenotypes. The objective of this study was aimed to elucidate biological roles of TaARF6 in mediating plant growth features under the conditions of Pi sufficiency and Pi deficiency. 【Methods 】The protein characterization of TaARF6 was predicted by the bioinformatics＇ tools. The seedlings of wheat（ cv. Shixin 828） were cultured underthe sufficient-and deficient-Pi conditions by a hydroponic approach and used to investigate the expression patterns of TaARF6 based on semi-quantitative RT-PCR. A DNA recombinant technique was adopted to construct the expression cassette integrating the TaARF6 open reading frame. The transgenic tobacco plants overexpressing TaARF6 were generated based on a genetic transformation approach mediated by Agobacterium-tumefaciens using the leaf discs as explants. Based on the culture methods of agar medium and hydroponic solution,the seedlings and plants of the transgenic Line 3 and Line 5 as well as wild type（ WT） were cultured to determine the growth features and to assay the fresh and dry weights of roots and aboveground tissues under the conditions of Pi sufficiency and Pi deficiency.【Results】1） TaARF6 encodes a transcription factor categoried into auxin response factor family and shares the conserved domains of ARF proteins in plants,such as the DNA binding domain and the auxin response domain. It shares a high identity to Bd ARF6 and Os ARF6,two ARF family members in B. distachyon and rice,respectively,at the amin