解无机磷细菌能够溶解土壤中的难溶性矿质磷酸盐，是解决土壤缺磷问题的新型途径之一。然而，解无机磷细菌的解磷能力受到可溶性磷的反馈抑制，其在土壤中的生理活性也受到可溶性磷的影响。前期研究发现，可溶性磷通过调控解无机磷细菌的葡萄糖代谢调节其有机酸分泌，进而影响其解磷能力，但该分子机制尚不明确。为了系统评估土壤环境中可溶性磷对解无机磷细菌解磷及植物接种效应的影响，阐明可溶性磷调控解无机磷细菌解磷的深层次机理，本项目拟对杨树根际解无机磷细菌类芽孢杆菌Paenibacillus sp. MP-J5在不同可溶性磷水平土壤中的解磷能力、杨树根际/根内定殖及促生作用进行测定；同时，利用RNA-seq技术对可溶性磷不足/充足条件下MP-J5菌株的转录组进行测序分析，解析可溶性磷调节其葡萄糖代谢途径转换的分子机制。本研究将为MP-J5菌株的田间应用提供指导，也为利用遗传育种技术对该菌株的Pi敏感性改造奠定基础。

Mineral phosphate-solubilizing bacteria (PSB) can release soluble phosphate from insoluble mineral phosphate. Application of PSB could be a novel solution to soil phosphate-deficiency. However, the phosphate solubilization of PSB is feedback inhibited by soluble phosphate, and the effects of soluble phosphate on physiological activities of PSB in soil still lack of systematic evaluation. Previous research demonstrated that soluble phosphate can regulate phosphate solubilization by PSB through regulating organic acids secretion, which is based on the regulation of glucose metabolism of PSB, yet the molecular mechanism is still unclear. Aim to evaluate the effects of soluble phosphate on phosphate solublization, inoculation efficacy of PSB in soil, the phosphate solubilization, colonization (inner tissue and rhizosphaere) and plant growth promotion of PSB strain Paenibacillus sp. MP-J5 be measured in soil with different soluble phosphate treatments. In order to reveal the deep mechanism of soluble phosphate effects on phosphate solubilization, the global gene expressions of the strain MP-J5 under phosphate-deficiency and phosphate-sufficiency on transcriptional level will be assess by using RNA-seq technique. Meanwhile, the molecular mechanism of the shift of glucose catabolism pathways by soluble phosphate will be revealed by the global transcriptome analysis. This work would provide valuable scientific guidance for further practical and commercial application of the strain MP-J5 and lay the foundation for molecular engineering strategy to reduce the sensitivity of PSB strain to soluble phosphate.