Establishment of a plant phosphorus utilization and weed control system based on phosphite and its dehydrogenase

Abstract

Nowadays, available phosphorus (P) deficiency in soil and weed resistance to herbicides have emerged as two severe limiting factors for sustainable agriculture. Therefore, it is of urgent needs to improve plant absorption/utilization ability of the soil P, seek phosphate (Pi)-alternative P fertilizers, and develop new forms of weed control systems. Phosphite (Phi), as a P resource of relatively high amount only less than Pi in Earth, can be converted to utilizable Pi uniquely in some bacterial species by oxidization via its specific dehydrogenase (PTDH), but inhibits plant growth and development. This implies that Phi might rather become a suitable P fertilizer for plants if introducing a PTDH detoxifier from bacteria. Herein, we created the transgenic tobaccos harboring a Pseudomonas PTDH gene (PsPtx) amplified from the soil metagenome previously. RT-PCR showed that the exotic PsPtx gene could express similarly in root, stem and leaf tissues of all transgenic lines. PsPtx transgenic tobaccos could utilize Phi by oxidization as the sole Pi supply, and also outperformed wild-type tobacco with a remarkably dominant growth under Phi stress conditions. Moreover, the PsPtx gene was preliminarily evaluated with a notable quality as a potential candidate of the selection marker in plant genetic transformation. Conclusively, PsPtx and its encoded phosphite dehydrogenase might be applicable for developing a dual system of plant phosphorus utilization and weed control using Phi as P fertilizer and herbicide, and provide an effectual solution to some obstacles in the current crop transgenic studies.