Negative regulation of phosphate starvation-induced genes.
Phosphate (Pi) deficiency is a major nutritional problem faced by plants in many agro-ecosystems. This deficiency results in altered gene expression leading to physiological and morphological changes in plants. Altered gene expression is presumed to be due to interaction of regulatory sequences (cis-elements) present in the promoters with DNA binding factors (trans-factors). In this study, we analyzed the expression and DNA-protein interaction of promoter regions of Pi starvation-induced genes AtPT2 and TPSI1. AtPT2 encodes the high-affinity Pi transporter in Arabidopsis, whereas TPSI1 codes for a novel gene induced in the Pi-starved tomato (Lycopersicon esculentum). Expression of AtPT2 was induced rapidly under Pi deficiency and increased with decreasing concentrations of Pi. Abiotic stresses except Pi starvation had no affect on the expression of TPSI1. DNA mobility-shift assays indicated that specific sequences of AtPT2 and TPSI1 promoter interact with nuclear protein factors. Two regions of AtPT2 and TPSI1 promoters specifically bound nuclear protein factors from Pi-sufficient plants. Interestingly, the DNA binding activity disappeared during Pi starvation, leading to the hypothesis that Pi starvation-induced genes may be under negative regulation.
Mukatira
U T
UT
Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907-1165, USA.
Liu
C
C
Varadarajan
D K
DK
Raghothama
K G
KG
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D028061:Phosphate Transport Proteins / Q000235:genetics* / Q000378:metabolism; D010710:Phosphates / Q000172:deficiency / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D028061:Phosphate Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; C105499:phosphate starvation-induced protein 1, plant