Phosphate dependent gene regulation

Phosphate (Pi) is an essential nutrient for all organisms. Plants need to mobilize Pi from the soil, taken and once taken up, Pi needs to be constantly recycled at the cellular level. Even when phosphorus is abundant in the rhizosphere the bioavailability is typically low. Consequently, plants have evolved an array of strategies to obtain adequate Pi-supply under limiting conditions. These strategies rely on regulation of a large number of genes and plants recruit specific proteins, transcriptions factors, which will recognize and activate or inactivate specific gene.

The aim of our research is to identify regulatory patterns in gene expression and in metabolism during P-starvation and to discover the molecular mechamisms behind this regulation of gene expression.

An important lead in this research area came with The discovery of a MYB-related transcription factors, PSR1 in  Chlamydomonas (Wykoff et al., 1999, PNAS 96: 15336) and PHR1 in Arabidopsis (Rubio et al., 2001, Gene Dev 15: 2122-33) which are involved in P-starvation signaling. In Arabidopsis, we can identify a family of related TFs likely to mediate nutrient starvation responses. Our research is focused on analysis of this specific family of transcriptions factors, on the role of  microRNAs in this regulation, and on interaction between Pi-regulation  and carbohydrate metabolism.

We are also involved in a collaborative project on the role of phosphate transporters in plants.

Arabidopsis plants with typical symptoms of P-starvation. Left: Low P. Right: High P.

 

Selected references:
Nilsson L, Müller R, Nielsen TH (2010) Dissecting the plant transciptome and the regulatory responses to phosphate. Physiologia Plantarum, Accepted

Nilsson L, . Müller R,  Nielsen TH (2007) Increased expression of a MYB-related transcription factor, PHR1, leads to enhanced P-uptake in Arabidopsis thaliana.  Plant Cell & Environment 30: 1499-1512

Müller R, Morant M, Jarmer H, Nilsson L, Nielsen TH (2007) Genome-wide analysis of the Arabidopsis leaf transcriptome reveals interaction of phosphate and sugar metabolism. Plant Physiology 143: 156-171.

Müller R, Nilsson L, Nielsen LK, Nielsen TH.  (2005) Interaction between phosphate starvation and hexokinase-independent sugar sensing in Arabidopsis leaves. Physiologia Plantarum, 124: 81-90

 

Müller R, Nilsson L, Krintel C, Nielsen TH.  (2004) Gene expression during recovery from phosphate starvation in roots and shoots of Arabidopsis thaliana. Physiologia Plantarum, 122: 233-243