| Potato is a crop which can be used as staple food, vegetables and raw materials for processing. The amount of potato production in China is lagest in the world. However, the late frost in spring and the early forst in autumn frequently threaten the crops grown in south and part of southwest China which cause severe yield loss. S. acaule and S. demissum are freezing tolerant and considered as important gene resources for potato breeding. In this study, several cultivars and wild species accessions were visually screened after natural frost and cold treatments, and the most sensitive one in the cultivars and the most tolerant one in the wild accessions were selected. The Tag-sequencing approach developed by Solexa was adopted to identify gene expression profiling of the selected materials under different cold treatments. The main results are as follows:1. The potato cultivas were visually screened respectively under-1,-2and-3℃for12h. The results showed that the plants were mostly damaged or died under-3℃for12h. A clone07HE5h-2was most tolerant to freezing and a clone1090806was most sensitive to freezing among the cultivars tested.2. Accessions of S. acaule and S. demissum were visually screened respectively under-1,-2and-3℃for12hours with cultivar07HE5h-2as control. The results showed that the palnts were mostly damaged or died under-3℃for12hours and accession SA-27of S. acaule exhibited the highest frozen-tolerance among the materials tested.3. The pathway enrichment analysis of the differential expressed genes under4℃for48hour showed that the sugar metabolism (including starch and sucrose metabolism, glycan degradation and pentose and glucuronate interconversions), lipid metabolism (including biosynthesis of unsaturated fatty acids, alpha-Linolenic acid metabolism and linoleic acid metabolism), plant hormone signal transduction and phenylpropanoid biosynthesis are important for the cold acclimation. The enrichment of arginine and pro line metabolism contributed to more hardness of S A-27. 4. The pathway enrichment analysis of the differential expressed genes under-1℃for12h after cultured at20℃showed that sugar metabolism and lipid metabolism contributed to the hardness of SA-27, including maltose metabolism, raffinose and other oligose metabolism and linoleic acid metabolism.5.29genes in4pathways were considered related to potato freezing tolerance through the patheway enrichment analysis and can be use as contidate genes for further research. |
