Proteome Analysis of Rice Leaf Under Phosphorus Deficiency

Phosphate (P) is one of the key substrates in energy metabolism and biosynthesis of nucleic acids and membranes. In order to identify molecular mechanisms involved in rice adaptation to P deficiency, we applied a proteomic approach to compare a rice parental line, Nipponbare (sensitive), and its near isogenic Line (Nil6-4) (resistant). The experiment was conducted using a completely randomized design with two treatments (1 and 100 mM KH2PO4) in three replications. Total soluble proteins were extracted from leaves of three independent replications of each treatment. Proteome analysis of leaf using two dimensional gel electrophoresis revealed that out of 875 proteins detected on leaf 2-DE gels, 65 proteins showed significant changes in response to P deficiency. Mass spectrometry analysis of responsive proteins resulted in identification of 43 leaf proteins. These proteins were involved in major P deficiency adaptation pathways including photosynthesis, defense, secondary metabolism, TCA cycle, transcription, protein synthesis and transport, phosphorus metabolism as well as proteins with unknown function. These proteins may play important roles in sensing the change of external P concentration and adaptation to P deprivation.