Acta Physiol Plant (2014) 36:1197–1210 DOI 10.1007/s11738-014-1496-x

Lixiang Cheng • Xin Zhang • Qingxia Zhao • Huijun Li • Yuping Wang • Dongxia Wang • Di Wang • Feng Zhang

L. Cheng Y. Wang D. Wang D. Wang (&) F. Zhang (&) Gansu Key Laboratory of Crop Improvement and Germplasm Enhancement/Gansu Provincial Key Laboratory of Aridland Crop Science, Research and Testing Center, Gansu Agricultural University, Lanzhou 730070, China e-mail: wangd@gsau.edu.cn
F. Zhang e-mail: zhangf@gsau.edu.cn
X. Zhang Q. Zhao H. Li F. Zhang College of Life Science and Technology, Gansu Agricultural University, Lanzhou, China

Abstract Cold-induced sweetening is one of the major factors limiting the quality of fried potato products. To understand the mechanisms of protein regulation for coldinducedsweeteninginpotatotubers,acomparativeproteomic approach was used to analyse the differentially expressed proteins both during control (25 C, 30 days) and cold treatment (4 C, 30 days) using two-dimensional gel electrophoresis.Quantitativeimageanalysesindicatedthattherewere25 protein spots with their intensities significantly altered more than twofold. Of these proteins, 9 were up-regulated, 13 were down-regulated,2wereabsent,and1wasinducedinthecoldstored tubers. The MALDI-TOF/TOF MS analyses led to the identification of differentially expressed proteins that are involvedinseveralprocessesandmightworkcooperativelyto maintain metabolic homeostasis in tubers during low-temperature storage. The preponderance of metabolic proteins reflects the inhibition of starch re-synthesis and the accumulation of sugars in carbon fluxes, linking starch–sugar conversion. The respiration-related proteins suggest the transfer of respiratory activity from aerobic respiration to anaerobic respiration in the cold-stored tubers. The proteins associated with defence appear to protect the tuber cells from low-temperature stress. Some heat shock proteins that act as chaperones also displayed a differential expression pattern, suggesting a potentially important role in cold-stored tubers, although their exact contribution remains to be investigated. The proposed hypothetical model might explain the interaction of these differentially expressed proteins that are associated with cold-induced sweetening in tubers.

Keywords Cold-induced sweetening 2-DE Differential expression Low-temperature storage MALDI-TOF/TOF MS Solanum tuberosum L.