Comparative proteomic analysis of QTL CTS-12 derived from wild rice (Oryza rufipogon Griff.), in the regulation of cold acclimation and de-acclimation of rice (Oryza sativa L.) in response to severe chilling stress

Rice (Oryza sativa L.) is a thermophilic crop vulnerable to chilling stress. However, common wild rice (Oryza rufipogon Griff.) in Guangxi (China) has the ability to tolerate chilling stress. To better understand the molecular mechanisms underlying chilling tolerance in wild rice, iTRAQ-based proteomic analysis was performed to examine CTS-12, a major chilling tolerance QTL derived from common wild rice, mediated chilling and recovery-induced differentially expressed proteins (DEPs) between the chilling-tolerant rice line DC90 and the chilling-sensitive 9311.Comparative analysis identified 206 and 155 DEPs in 9311 and DC90, respectively, in response to the whole period of chilling and recovery. These DEPs were clustered into 6 functional groups in 9311 and 4 in DC90. The majority were enriched in the 'structural constituent of ribosome', 'protein-chromophore linkage', and 'photosynthesis and light harvesting' categories. Short Time-series Expression Miner (STEM) analysis revealed distinct dynamic responses of both chloroplast photosynthetic and ribosomal proteins between 9311 and DC90.CTS-12 might mediate the dynamic response of chloroplast photosynthetic and ribosomal proteins in DC90 under chilling (cold acclimation) and recovery (de-acclimation) and thereby enhancing the chilling stress tolerance of this rice line. The identified DEPs and the involvement of CTS-12 in mediating the dynamic response of DC90 at the proteomic level illuminate and deepen the understanding of the mechanisms that underlie chilling stress tolerance in wild rice.