【摘要】 由于难溶性矿物磷酸盐和有机磷的大量存在,土壤总磷虽高,但多数土壤缺乏有效磷,这是世界范围内农业生产的主要限制因素之一。土壤中有机磷的存在形式主要是植酸,为了提高土壤有效磷供给,利用根癌农杆菌菌株LBA4404,通过两步再生方法将植物表达载体pBINPR-phyI中含有的带胞外分泌信号肽序列的植酸酶基因转入油菜品种中双6号中,并获得转基因油菜56株,转化效率0.16%~9.20%。分子检测和酶活性检验表明,植酸酶基因已导入中双6号,转基因植株能有效表达植酸酶基因并向根外分泌植酸酶,转基因植株能以植酸为唯一磷源正常生长,非转基因植株则不能。结果表明,转基因植株根系分泌大量高活性植酸酶有助于土壤中有机磷释放出有效磷供植物利用;利用基因工程技术提高植物对土壤闭蓄态有机磷利用效率的前景是可期待的。更多还原

【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 0.16–9.20%. 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.更多还原