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Abstract：
CONCLUSIONS: The small 295-bp ZmPht1; 5 promoter is sufficient to drive high-intensity expression of target genes, especially under phosphate deprivation conditions, and is therefore useful for crop improvement via transgenic techniques. Phosphate (Pi) deficiency has become a major challenge and limiting factor in world agricultural production. Manipulating the gene expression using appropriate promoters to improve the Pi absorption and utilization efficiency of crops could reduce the requirement for Pi fertilizers. In the study, a 295-bp strong promoter (M2P-7) of maize high-affinity phosphate transporter ZmPht1; 5 was isolated and functionally validated in transgenic Nicotiana benthamiana and maize by analyzing the ZmPht1; 5 promoter (M2P-1) and its 5\' truncated variants (M2P-2 ~ M2P-8) in different sizes under normal and Pi-deprivation conditions. The M2P-7 displayed the highest promoter activities among 5\' truncated fragments in all tested tissues of transgenic Nicotiana benthamiana at different development stages, which was 1.5 and 3 times higher than the well-used CaMV35S promoter under normal and Pi-deprivation conditions, respectively. In maize, the M2P-7 promoter activity was comparable to the maize ubiquitin1 promoter widely used in monocots under normal condition, which was about 1.3 times that of the ubiquitin1 promoter under Pi-deprivation environments. Moreover, the M2P-7 fragment is only 295 bp in length, thus reducing the construct size, and is therefore beneficial for genetic transformation. Thus, the small promoter M2P-7 of plant origin could be of great use for monocotyledonous and dicotyledonous crop improvement via transgenic techniques based on its promoter activities, expression patterns and small size.
摘要：
结论：小295-bp的ZmPht1;5启动子足以驱动靶基因的高强度表达，特别是在磷酸盐剥夺条件下，因此可用于通过转基因技术改良作物。磷酸盐（Pi）缺乏已成为世界农业生产中的主要挑战和限制因素。使用适当的启动子操纵基因表达以提高作物的Pi吸收和利用效率可以减少对Pi肥料的需求。在研究中,玉米高亲和力磷酸盐转运蛋白ZmPht1的295bp强启动子（M2P-7）；通过分析ZmPht1；5启动子（M2P-1）及其5'截短变体（M2P-2〜M2P-8），在正常和Pi剥夺条件下，在转基因烟草和玉米中分离并进行了功能验证。M2P-7在转基因烟草在不同发育阶段的所有测试组织中的5个截短片段中显示出最高的启动子活性，在正常和Pi剥夺条件下，比使用良好的CaMV35S启动子高1.5和3倍，分别。在玉米中，在正常条件下，M2P-7启动子活性与单子叶植物中广泛使用的玉米泛素1启动子相当，在Pi剥夺环境下，约为泛素1启动子的1.3倍。此外，M2P-7片段只有295bp长,从而减小了结构的大小，因此有利于遗传转化。因此，植物来源的小启动子M2P-7通过基于其启动子活性的转基因技术可用于单子叶和双子叶作物的改良，表达模式和小尺寸。
