Study On Soil Phosphorus Uptake And Utilization Of Transgenic Canola

The bioavailability of soil phosphorus (P) is low due to its binding to soil mineral surfaces, low solubility, difficulty to move and some other reasons. Most of phosphate in acidity and alkaline soils is insoluble, and 50% to 80% of total phosphorus in soils belongs to organic P. All of these seriously impact on crop growth and yield. So, P has been one of the major limting factors for plant growth. Canola is an important oilseed crop in the world and it is sensitive to phosphorus deficiency. Middle and lower reaches of the Yangtze River is main producing areas of rapeseed in China, while the P availability of this region in soil is low, which will inevitably affect the rapeseed production. In order to enhance the phosphate efficiency and ensure the crop yield, 30 millins tons of phosphate fertilizer is used annually. Because of absorption, deposiation or turn into organic phosphorous form, over 80% of fertilized phosphate can't be utilized by plants. So, enhancing the plant utilization ability to soil phosphorus will play an import role in improving crop production and agro-ecological environment. Researches had been reported that increasing the secretion of organic acid could enhance plant utilization of insoluble phosphate and Al tolerance. Besides, increasing phytase secretion could enhance plant utilization of organic phosphorus. In this study, we obtained transgenic canola which overexpress CS, phyA and appA gene, respectively, by genetic engineering, and then the ability of the transgenic plants to absorb and utilize insoluble and organic phosphorus in soil were evaluated. The main results were as follows:1. Forty nine transgenic plants were obtained, nineteen, twenty-three, and seven of which were transformed with the vector of pBI121-CSb, pBI121-appA and pBI121 -phyA, respcetively.2. The expression of transgenes was further confirmed by RT-PCR and Northern blot. It was showed that the foreign gene can stably express in transgenic plants.3. The phynotype of CS transgenic lines were evaluated by pot culture. The results were showed that the transgenic plants grew better than wild type under low phosphorus and insoluble phosphate condition. The shoot biomass of transgenic plants was 2 to 4 times higher than wild type in seedling period, so did the P accumulation. When exposed to Al solution, the CS activity of CS3 was more than two times higher than wild type.4. The phynotype of phytase transgenic lines were detected by pot culture. The results were showed that the transgenic plants grew better than wild type when phytate was used as the only P source. And the transgenic line P1 has higher seed yield than WT. These results should be verified by futher research using transgenic homozygous.