Response analysis of potato italicPYL5/italic gene to abiotic stress and activity identification of its promoter

Objective Abscisic acid(ABA),as a stress hormone,plays an important role in plant growth,development,and response to abiotic stresses such as drought and salt.PYR/PYL/RCARs(referred to as "PYL" hereafter)as ABA receptors in various plants,are widely studied.Based on the bioinformatics and expression pattern analysis of potato StPYL5 gene and the identification of its promoter activity,this study provides a basis for further revealing the function of potato StPYL5 and resistance breeding. Method In this study,StPYL5 gene was cloned based on transcriptome data.The molecular characteristics of StPYL5 was analyzed using software such as DNAMAN and MEGA.The tissue specificity of the StPYL5 gene and its response to abiotic stress were examined by qPCR.The StPYL5 gene promoter was analyzed using the PlantCARE website,and its activity was identified through transient transformation in tobacco. Result The results showed that the full-length of the StPYL5 gene was 534 bp,encoding 177 amino acids.The protein had a molecular weight of 20.19 ku,and the theoretical isoelectric point(pI)was 5.97.Phylogenetic analysis revealed a close relationship between StPYL5 and SpPYL9-like.Tissue specificity analysis showed that the expression pattern of StPYL5 in potato cultivar Qingshu 9(QS9)was the highest in leaves and roots,followed by stems,flowers,and tubers.Expression analysis under different stresses showed that the expression level of StPYL5 in QS9 increased initially and then decreased under drought,low temperature,salt,and ABA stress.The expression of StPYL5 was induced by MeJA and SA.In addition,a 2 000 bp StPYL5 gene promoter was successfully cloned.Tissue staining after transient transformation in tobacco demonstrated that the StPYL5 gene promoter had promoter activity to drive downstream GUS reporter gene expression. Conclusion This study comprehensively analyzed the molecular characteristics of the StPYL5 gene and its expression profile under various abiotic stresses.The successful cloning of the active pStPYL5 promoter provides a foundation for further investigating the function of the StPYL5 gene and potato breeding for stress tolerance.