Transgenic soybean with low phytate content constructed by Agrobacterium transformation and pollen-tube pathway

The expression of a microbial phytase in transgenic plants may create a new biochemical pathway that mobilizes its endogenous phytate and release inorganic phosphate from it, so that more phosphorus is available for plant growth. In this study, transgenic soybean plants were generated via both Agrobacterium transformation and pollen tube pathway with the PhyA gene of Aspergillus ficuum. The optimal concentrations of plant hormones including N₆-benzylaminopurine (BAP), gibberellin (GA₃) and indole-3-butyric acid (IBA) were tested based on their effectiveness on promoting the growth of transgenic explants. Genomic PCR results and Southern blot hybridization analysis showed that transgenic soybean plants selected for resistance to kanamycin contained the phyA transgene. The transgenic soybean plants with phyA gene integrated in their genome exhibited lower amount of phytate in different soybean tissues including leaf, stem and root, which indicated that engineering crop plants with a higher expression level of heterologous phytase could improve the degradation of phytate and potentially in turn mobilize more inorganic phosphate from phytate and thus reduce phosphate load on agricultural ecosystems.