Comparison of chitosan-induced protein patterns in ‘Leung Pratew123’ rice Oryza sativa L. ‘Leung Pratew123’ and its drought resistant mutant line, LEUNG PRATEW123-TC171, during drought stress

Previous study showed that ‘Leung Pratew123’ rice (LPT123), a drought sensitive line, was more responsive to chitosan during drought stress than its drought resistant mutant line, Leung Pratew123-TC171 (LPT123-TC171). This study aimed to compare chitosan-induced protein patterns in LP123 and LPT123-TC171 rice during drought stress by proteomics approach to display differentially expressed proteins and protein profiles. Plants were applied with 40 mg/L of 80% deacetylated oligomeric chitosan (O80) by seed soaking for 24 hrs and foliar spraying when seedlings were fifteen and thirty days old. Then plants were subjected to 10% polyethylene glycol (PEG) 6000 for 0, 2, 6 and 24 hrs. Total protein was extracted from rice leaf and root tissues and then total proteome were analyzed with GeLC-MS/MS. Chitosan-responsive proteins during drought stress in LPT123 rice were 401 and 115 proteins in leaf and root tissues, respectively. In LPT123-TC171 rice. Chitosan-responsive proteins were 314 and 88 proteins in leaf and root tissues, respectively. These proteins were classified into several functional groups. Proteins with unknown function, transposable element, metabolic process were the predominant groups. Transcriptional repressor was selected for investigation at transcriptional level. The quantitative reverse transcription polymerase chain reaction analysis of transcriptional repressor gene expression revealed that the tendency of expression was consistent with proteomic data. The potential role of the gene in chitosan-induced drought tolerance in tice was discussed.