Interdepartmental Plant Biology Major, Iowa State University, Ames, IA, 50011-1010, USA.
Department of Agronomy, Iowa State University, Ames, IA, 50011-1010, USA.
Plant Cell Rep. 2016 May;35(5):1121-32. doi: 10.1007/s00299-016-1942-x. Epub 2016 Feb 16.
Bacterial phosphite oxidoreductase gene and chemical phosphite can be used as a selection system for Agrobacterium -mediated maize transformation. Application of phosphite (Phi) on plants can interfere the plant metabolic system leading to stunted growth and lethality. On the other hand, ectopic expression of the ptxD gene in tobacco and Arabidopsis allowed plants to grow in media with Phi as the sole phosphorous source. The phosphite oxidoreductase (PTXD) enzyme catalyzes the conversion of Phi into phosphate (Pi) that can then be metabolized by plants and utilized as their essential phosphorous source. Here we assess an alternative selectable marker based on a bacterial ptxD gene for Agrobacterium-mediated maize transformation. We compared the transformation frequencies of maize using either the ptxD/Phi selection system or a standard herbicide bar/bialaphos selection system. Two maize genotypes, a transformation amenable hybrid Hi II and an inbred B104, were tested. Transgene presence, insertion copy numbers, and ptxD transcript levels were analyzed and compared. This work demonstrates that the ptxD/Phi selection system can be used for Agrobacterium-mediated maize transformation of both type I and type II callus culture and achieve a comparable frequency as that of the herbicide bar/bialaphos selection system.
细菌亚磷酸盐氧化还原酶基因和化学亚磷酸盐可用作农杆菌介导的玉米转化的选择系统。亚磷酸盐（Phi）在植物上的应用会干扰植物的代谢系统，导致生长迟缓和致死。另一方面，ptxD 基因在烟草和拟南芥中的异位表达使植物能够在以 Phi 为唯一磷源的培养基中生长。亚磷酸盐氧化还原酶（PTXD）酶催化将 Phi 转化为可被植物代谢并用作其必需磷源的磷酸盐（Pi）。在这里，我们评估了一种基于细菌 ptxD 基因的替代选择标记，用于农杆菌介导的玉米转化。我们比较了使用 ptxD/Phi 选择系统或标准除草剂 bar/bialaphos 选择系统的玉米转化频率。测试了两种玉米基因型，一种是可转化的杂种 Hi II，另一种是自交系 B104。分析和比较了转基因的存在、插入拷贝数和 ptxD 转录本水平。这项工作表明，ptxD/Phi 选择系统可用于农杆菌介导的玉米转化，包括 I 型和 II 型愈伤组织培养，并且与除草剂 bar/bialaphos 选择系统的频率相当。
