Overexpression of LbPT7 Promotes Phosphorus Uptake by Plants and Affects Phosphorus Uptake by Arbuscular Mycorrhizas under High Phosphorus Condition

Previous studies have proved that arbuscular mycorrhizal fungi infection and phosphate transporters are particularly important for phosphorus uptake by plants. Early laboratory studies found that LbPT7 played a role in Pi uptake and it was affected by arbuscular mycorrhizal fungi. In order to verify the phosphorus uptake function of LbPT7 gene and the effect of interaction with arbuscular mycorrhiza on plants, we constructed LbPT7 overexpression vector with Nicotiana tabacum and obtained T1 generation overexpression positive plants as test material. Under the condition of pot experiment, we designed three factors: Arbuscular Mycorrhizal Fungi treatment, genotype treatment, phosphorus concentration treatment. After 4 weeks of treatment, we measured the biomass and phosphorus content of tobacco, and determined the colonization. The results showed that overexpression of LbPT7 can promote plant phosphorus uptake and inoculation of AM fungi further promote plant phosphorus uptake in phosphorus deficiency condition, but this effect of them can't superpose in phosphorus adequate conditions. Overexpression of LbPT7 promoted the absorption of phosphorus, but impeded the utilization of phosphorus of N. tabacum in phosphorus deficiency condition. Overexpression of LbPT7 had little effect on the colonization of AM fungi in N. tabacum.