Identification of drought-resistant resources and preliminary screening of drought resistant genes in diploid potatoes

In this study, drought-shelter controlled irrigation experiments were conducted on 75 tissue-cultured seedling clones derived from hybrid progeny of the diploid cultivated species PHU-STN. Seven traits, measurements including biomass, root-related indicators, and physiological indices under drought stress, were measured for each potato accession. Drought stress indices were calculated for each trait, and a comprehensive evaluation was performed using membership function analysis combined with principal component and cluster analyses. Based on the results, the materials were classified into four levels of drought resistance, and two highly drought-resistant clones (A90 and A204) were identified. Subsequently, A90 (high drought resistance) and A163 (low drought resistance) were subjected to PEG-6000-induced drought stress for sampling and analysis. Transcriptome sequencing was employed to explore the regulatory mechanisms underlying drought response and to identify drought-resistance- related genes. Differentially expressed genes (DEGs) were analyzed in A90 and A163 under PEG-6000 stress. GO functional annotation and KEGG pathway enrichment analyses revealed key regulatory genes involved in ethylene and auxin signaling pathways. Based on differential expression patterns and qRT-PCR validation, six candidate drought-resistance genes were identified, all associated with auxin and ethylene signaling pathways.