Abstract:

Phosphorus (P) deficiency in soil is a major constraint in agricultural production worldwide. Most soils contain significant amounts of total soil P that occurs in insoluble inorganic and organic fractions, but lack available phosphorus. Phytic acid is the major storage form of organic phosphorus in soil. In this experiment, the phytase gene with the signal peptide sequence of extracellular secretion was introduced into Brassica napus cv. Zhongshuang 4 via Agrobacterium tumefaciens LBA4404. Fifty six plants of transgenic Brassica napus were obtained and checked by PCR and phytase activity, most of them gave the positive results. The transformation efficiency was 0.16–9.2%. When grown in MS medium with phytic acid as a sole phosphorus source under sterile conditions, transgenic Brassica napus plants were able to obtain inorganic phosphate from phytic acid and grew normally, but the wild-type plants not. These results show that extracellular phytase secreted from plant roots is a significant factor in the utilization of phosphorus from phytate and indicate that there exists a prospect for using gene technology to improve the ability of plants to utilize accumulated forms of soil organic phosphorus.

Key words: Brassica napus, Phytase, Transgene, Extracellular secretion