Differential Expression Analysis of Genes Related to Starch and Sucrose Metabolic Pathways in Potato Tubers under Drought Stress

As a kind of signal molecule, carbohydrate regulates crop growth and development and ecological adaptability under drought stress. To explore the molecular mechanisms of potato (Solanum tuberosum L.) tuber under drought stress, the present study the potato "Cooperation 88" variety using the potato tuber samples under different degrees (normal, moderate, severe) drought stress were sequenced by Illumina Hiseq 2500 sequencing technology and annotate transcripts of the differentially expressed genes obtained. Our study screened five enzyme genes and random genes involved in starch and sucrose metabolic pathways that were further verified by real-time quantitative PCR (qPCR). Applied different level of drought stress in potato tubers up-regulated 4476 genes and 4490 genes were down-regulated. A total of 164 differentially expressed genes (DEGs) were found under the three applied treatments. Gene ontology (GO) functional enrichment analysis displayed that DEGs accounted for the largest proportion in metabolic pathways, molecular functions were associated with the catalytic enzyme activities and binding, cellular components were mainly located in cells and membranes. KEGG metabolic pathway annotation suggested total of 124 metabolic pathways, and the enrichment of DEGs were the largest in the energy metabolism and carbohydrate metabolism. Five genes involved in the metabolic synthesis of starch and sucrose were screened out are SS, TPS11, SPS2, BGLU12 and BACOVA_02659 and random selected 5 genes were GRXS17, CATHB1, CKA2F, RFS2 and PABN1. The qPCR validation results were consistent with the RNA-seq data (transcriptomics), which proved the reliability of transcriptome data. Ten genes involved in the regulation of starch and sucrose metabolic pathways in potato tubers under drought stress. Our results concluded that different molecular mechanisms of DEGs in potato starch and sucrose metabolic pathways were explored under different degrees of drought stress.