Although extensive studies have demonstrated that many drought-responsive genes confer drought toler- ance to plants, comparisons of the drought tolerance capa- bilities conferred by different genes under various natu...Although extensive studies have demonstrated that many drought-responsive genes confer drought toler- ance to plants, comparisons of the drought tolerance capa- bilities conferred by different genes under various natural conditions have seldom been reported. We evaluated and compared the effects of two sets of transgenes, the drought- responsive genes （AtDREBIB and AtCBL1） and the root architecture-regulated genes （iaaM and AtCKX）, on drought tolerance in Nicotiana tabacum plants subjected to different conditions. The expression of AtCKX3 driven by a root- specific promoter PYKIO （designated hereafter as PIO; PIO：AtCKX3）, 35S：AtCKX3, or PlO：iaaM promoted root growth and development. Compared to plants harboring PIO：AtCKX3, 35S：AtCKX3, PlO：iaaM, or the empty vector, those carrying 35S：AtDREB1B, 35S：AtCBLl, or 35S：iaaM exhibited increased drought tolerance under laboratory- controlled conditions. Conversely, in field conditions, plants transformed with 35S：AtDREB1, 35S：AtCBL1, or 35S：iaaM were sensitive to drought stress. Under field conditions, drought stress dramatically reduced the growth and seed production of plants harboring 35S：AtDREBIB, 35S：A tCBL1, 35S：iaaM, or the empty vector, whereas it had little effect on plants carrying PIO：AtCKX3, 35S：AtCKX3, or PlO：iaaM. This study demonstrates that a plant＇s tolerance to drought stress changes with environmental conditions, and our results indicates that manipulating the expression of genes that control root architecture may be important for engineering plants with improved drought tolerance in natural conditions.展开更多
基金This work was supported by the National Nat- ural Science Foundation of China （31171921, 31101527 and 31471851）, the National High Technology Research and Develop- ment Program of China （2011AA100204） and Doctoral Fund of Ministry of Education of China （20110008120024）.
文摘Although extensive studies have demonstrated that many drought-responsive genes confer drought toler- ance to plants, comparisons of the drought tolerance capa- bilities conferred by different genes under various natural conditions have seldom been reported. We evaluated and compared the effects of two sets of transgenes, the drought- responsive genes （AtDREBIB and AtCBL1） and the root architecture-regulated genes （iaaM and AtCKX）, on drought tolerance in Nicotiana tabacum plants subjected to different conditions. The expression of AtCKX3 driven by a root- specific promoter PYKIO （designated hereafter as PIO; PIO：AtCKX3）, 35S：AtCKX3, or PlO：iaaM promoted root growth and development. Compared to plants harboring PIO：AtCKX3, 35S：AtCKX3, PlO：iaaM, or the empty vector, those carrying 35S：AtDREB1B, 35S：AtCBLl, or 35S：iaaM exhibited increased drought tolerance under laboratory- controlled conditions. Conversely, in field conditions, plants transformed with 35S：AtDREB1, 35S：AtCBL1, or 35S：iaaM were sensitive to drought stress. Under field conditions, drought stress dramatically reduced the growth and seed production of plants harboring 35S：AtDREBIB, 35S：A tCBL1, 35S：iaaM, or the empty vector, whereas it had little effect on plants carrying PIO：AtCKX3, 35S：AtCKX3, or PlO：iaaM. This study demonstrates that a plant＇s tolerance to drought stress changes with environmental conditions, and our results indicates that manipulating the expression of genes that control root architecture may be important for engineering plants with improved drought tolerance in natural conditions.
