Proteomic analysis of PEG-simulated drought stress-responsive proteins of rice leaves using a pyramiding rice line at the seedling stage

Drought is one of the most severe limitations on the productivity of rice. To investigate the response of rice to drought stress, changes in protein expression were analyzed using a proteomic approach in a drought tolerant quantitative trait locus (DT QTL) pyramiding rice line PD86 by way of PEG simulated drought stress. After drought stress for 8 days, 23 proteins increased in abundance and the level of five proteins decreased. Twelve of the drought-responsive proteins were identified by mass spectrometry. These proteins are involved in redox metabolism, photosynthesis, cytoskeleton stability, defense, protein metabolism, and signal transduction. Among the identified proteins, peroxiredoxin, ribonuclease and putative chitinase, coincided with three QTL regions carried by PD86; in addition, voltage-dependent anion-selective channel protein, ribonuclease and putative chitinase, co-localized with DT QTLs on the chromosome. The expression patterns of sonic of the corresponding genes were further analyzed at the mRNA level using real-time RTPCR. The comprehensive results suggested that the differentially displayed proteins might play a role in redox metabolism, photosynthesis, protein degradation, cytoskeleton organization and programmed cell death in the DT mechanism of rice.