Argonaute (AGO) proteins are core components of the RNA-induced silencing complex (RISC) and play a crucial role in small RNA (sRNA)-mediated gene silencing. In plants, AGO proteins regulate key biological processes such as development, stress responses, genome architecture, and pathogen defense. However, the AGO gene family in potato (Solanum tuberosum L.) has not yet been characterized. In this study, we identified members of the StAGO gene family through bioinformatics approaches and analyzed their expression patterns in various tissues and in leaves infected by Phytophthora infestans (Mont.) de Bary using real-time quantitative PCR (RT-qPCR). The expression of StAGO1A and StAGO2A under pathogen stress was further validated using a transient expression assay in Arabidopsis protoplasts. A total of 14 StAGO genes were identified in the doubled haploid potato genome, distributed across seven chromosomes. Phylogenetic analysis grouped them into three subfamilies: StAGO1A, StAGO1B, StAGO5, StAGO10, StAGO10A; StAGO2A, StAGO2B, StAGO3, StAGO7; and StAGO4A, StAGO4B, StAGO4, StAGO6, StAGO8. Collinearity analysis revealed two segmental duplication events within the family (StAGO1A and StAGO1B, StAGO4A and StAGO4B). Tissue-specific expression analysis by RT-qPCR showed that StAGO10 was highly expressed in leaves, StAGO1B showed elevated expression in stems, and StAGO3, StAGO5, and StAGO7 exhibited relatively high expression in mini tubers. Moreover, expression profiling following infection with the late blight pathogen revealed significant upregulation of StAGO1A, StAGO2A, StAGO3, StAGO5, StAGO6, and StAGO10. Transient expression assays in Arabidopsis protoplasts further confirmed that P. infestans infection induces the expression of StAGO1A and StAGO2A. In conclusion, this study provides a theoretical foundation for future functional analyses of the StAGO gene family and their roles in potato defense against late blight.
Tian et al. (Wed,) studied this question.