Screening of salt-tolerant potato germplasms and dynamic changes of APA in response to salt stress

Soil salinization is one of the most prominent abiotic stresses affecting agricultural production. As the third most significant staple crop, the potato exhibits heightened sensitivity to salt stress. Alternative polyadenylation (APA) is a key regulator of gene expression, significantly impacting plant growth and stress response. However, the role of APA in response to salt stress remains elusive in potato, as genetic resources for salt-tolerant potatoes are limited. In this study, germplasms of nine salt-sensitive and seven salt-tolerant accessions were screened, respectively. Salt-tolerant germplasms exhibited superior ROS scavenging capabilities and ionic balance compared to salt-sensitive germplasms. This study characterized APA events in leaves and roots of Morocco 1 (salt-tolerant) and Qingshu 9 (salt-sensitive) under control and salt stress using TAIL-seq. Salt stress induced global APA dynamics in potato. A total of 1831 and 4235 APA genes were identified in the leaves and roots of Qingshu 9, respectively. In contrast, Morocco 1 exhibited only 559 and 2696 APA genes in its leaves and roots, respectively. APA led to an average extension of the 3’ UTR of most genes by 25 bp. Moreover, five candidate genes potentially responsive to salt stress via APA were identified. In summary, our results illustrate that APA is significant for regulating gene expression under salt stress, providing new perspectives for studying salt tolerance in potato.