Regulation of Gene activity in Plants: The phosphate starvation rescue system

Phosphorus is one of the key macronutrients necessary for the growth of plants and of any living organism. Plants preferentially absorb phosphorus in the form of phosphate (Pi), which is a quite immobile and insoluble ion in the soil. This has made Pi availability a major limiting factor in plant growth and productivity. Implementing sustainable agricultural practices requires the generation of plants with improved Pi acquisition and use efficiency. In this context, it is of importance study of the Pi starvation rescue system in plants, which consists on an array of adaptive responses evolved by plants  to cope with growth under low Pi regimens by increasing the efficiency in Pi acquisition and use and to protect the plant from the stress caused by Pi starvation. In our laboratory we have been working for the last 20 years in the genetic dissection of the signaling pathway of Pi starvation in plants, and have identified key signaling genes, particularly the PHR1 master transcription factor and the SPX sensor. At present, we are exploring natural variation of the Pi starvation transcriptome as well as of physiological responses. In addition,  we are seeking to identify candidate transcription factors acting in concert with PHR1 to control these responses.  The two positions offered to perform the TFM work relate to these objectives. Thus one student will  contribute to the study of natural variation based on RNA-seq analysis using GWAS approaches. The second student will contribute to the identification of novel transcription factors regulating Pi starvation responses, following an strategy involving 1) bioinformatic generation of coexpression network, based on available transcriptomic data in our laboratory 2) Search for transcription factors whose binding sequence is enriched in the promoters of any of the coexpression clusters of Pi starvation responsive genes, and  3) experimental validation in planta using transient expression assays ( involving the expression of reporter genes generated with promoters of Pi starvation responsive genes fused to the coding region of the luciferase, either alone or  in combination with constructs overexpressing  the candidate transcription factors, plus/minus that of PHR1).