转枯草芽孢杆菌植酸酶基因烟草对不同介质中植酸磷的吸收利用

利用转入枯草芽孢杆菌植酸酶基因的不同烟草株系,分别在无菌培养基、砂培和土培试验中研究了转植酸酶基因烟草对植酸磷的吸收和利用.结果表明,在无菌培养基试验中,所有转植酸酶基因烟草对植酸磷的吸收利用能力均显著高于野生型,其生物量比野生型提高了3.6～10.7倍,总磷吸收量提高了2.2～4.6倍;在沙培和土培中,转植酸酶基因烟草对植酸磷的吸收利用与野生型相比,生物量和总磷吸收量差异不显著.这说明转植酸酶基因在无菌条件下可以提高植物吸收利用植酸磷的能力,但是在自然条件下,由于微生物分解或矿物固定等原因,其作用不稳定,需要进一步研究克服土壤中的限制因素,才能使转基因植物充分发挥作用.

Phytate-phosphorus uptake and utilization by transgenic tobacco carrying Bacillus subtilis phytase gene

Phytate is the major form of organic phosphorus in soil. Elevating the phyrase activity in transgenic plants may be an effective approach to promote their phytate-phosphorus utilization, but little is known about the applied conditions. In this study, several transgenic tobacco lines carrying Bacillus subtilis phytase gene were compared with wild-type tobacco, in terms of their ability in acquiring phosphorus from phytate in sterilized agar, sand and soil. In sterilized agar, transgenic tobacco plants were more efficient in phytate-phosphorus uptake and utilization, and their biomass and total phosphorus content were 3.6-10.7 and 2.2-4.6 fold of the wild-type's, respectively. In sand and soil systems, however, there were no significant differences in biomass and total phosphorus content between the trsansgenic and wild-type tobacco plants. These results indicated that Bacillus phytase transgene could only improve the phytate-phosphorus uptake by transgenic plants under sterilized condition, and its effectiveness might be limited under natural conditions because of microbial decomposition and mineral fixation. Therefore, further research is needed to understand the limiting factors on the functions of the transgene.