Development of an In Planta system to monitor phosphorus status by agroinfiltration and agroinjection

Background and Aims: An optimal supply of phosphate (Pi) fertilizer is important to ensure crop yield and quality and to maintain agricultural sustainability. In this study, an in planta monitoring system was developed to conveniently monitor the P status of crops. Methods: A phosphate starvation-induced gene (TPSI1) from tomato (Solanum lycopersicum L.) was used to reflect P status in plants. Using agroinfiltration and agroinjection techniques, the GUS reporter gene driven by the TPSI1 promoter was transiently expressed in tobacco (Nicotiana benthamiana) leaves and tomato fruits to reflect their P status. Results: We showed that the vegetative growth of tobacco and the yield and quality of tomato were affected by the supply of Pi fertilizer. We further demonstrated that the expression of a GUS reporter gene driven by the TPSI1 promoter could accurately report on P status in tobacco leaves and tomato fruits in real time. Expression of the GUS reporter gene was independent of deficiencies in mineral nutrients other than P, demonstrating the specificity of this system. Conclusions: The above results indicate that the employed agroinfiltration/agroinjection-based diagnostic system is useful for monitoring P status in plants. © 2016, Springer International Publishing Switzerland.