Holme Inger Baeksted, Dionisio Giuseppe, Madsen Claus Krogh, Brinch-Pedersen Henrik
Department of Molecular Biology and Genetics, Faculty of Science and Technology, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark.
Plant Biotechnol J. 2017 Apr;15(4):415-422. doi: 10.1111/pbi.12636. Epub 2016 Nov 1.
The phytase purple acid phosphatase (HvPAPhy_a) expressed during barley seed development was evaluated as transgene for overexpression in barley. The phytase was expressed constitutively driven by the cauliflower mosaic virus 35S-promoter, and the phytase activity was measured in the mature grains, the green leaves and in the dry mature vegetative plant parts left after harvest of the grains. The T -generation of HvPAPhy_a transformed barley showed phytase activity increases up to 19-fold (29 000 phytase units (FTU) per kg in mature grains). Moreover, also in green leaves and mature dry straw, phytase activities were increased significantly by 110-fold (52 000 FTU/kg) and 57-fold (51 000 FTU/kg), respectively. The HvPAPhy_a-transformed barley plants with high phytase activities possess triple potential utilities for the improvement of phosphate bioavailability. First of all, the utilization of the mature grains as feed to increase the release of bio-available phosphate and minerals bound to the phytate of the grains; secondly, the utilization of the powdered straw either directly or phytase extracted hereof as a supplement to high phytate feed or food; and finally, the use of the stubble to be ploughed into the soil for mobilizing phytate-bound phosphate for plant growth.
对在大麦种子发育过程中表达的植酸酶紫色酸性磷酸酶（HvPAPhy_a）作为大麦过表达转基因进行了评估。该植酸酶由花椰菜花叶病毒35S启动子组成型驱动表达，并在成熟籽粒、绿叶以及收获籽粒后剩余的干燥成熟营养植物部分中测量了植酸酶活性。HvPAPhy_a转化大麦的T代显示植酸酶活性增加高达19倍（成熟籽粒中每千克29000植酸酶单位（FTU））。此外，在绿叶和成熟干秸秆中，植酸酶活性也分别显著增加了110倍（52000 FTU/kg）和57倍（51000 FTU/kg）。具有高植酸酶活性的HvPAPhy_a转化大麦植株在提高磷生物有效性方面具有三重潜在用途。首先，将成熟籽粒用作饲料，以增加与籽粒植酸盐结合的生物可利用磷和矿物质的释放；其次，直接利用粉状秸秆或将从中提取的植酸酶用作高植酸饲料或食物的补充；最后，将茬翻耕到土壤中，以调动与植酸盐结合的磷用于植物生长。
