Genome-wide analysis of the potato GRF gene family and their expression profiles in response to hormone and Ralstonia solanacearum infection.

Background: Potato (Solanum tuberosum L.) is one of the most economically significant crops globally. Nevertheless, potato cultivation is becoming increasingly susceptible to a multitude of diseases, including bacterial wilt, which is caused by Ralstonia solanacearum.

Objective: To identify the GRF gene family in potatoes and to examine their expression profiles in response to hormones and R. solanacearum infection.

Methods: A comprehensive genome-wide analysis was conducted to identify the GRF gene family in the potato genome.

Results: A total of 13 GRF genes were identified from the latest potato genome, including five StGRFs belonging to the ɛ group and eight of the non-ɛ group. The transcriptional responses of the StGRFs to two biotic stress-related phytohormones (SA and MeJA) were defined, as well as the response to infection with R. solanacearum in a bacterial wilt-sensitive cultivar, S. tuberosum 'Qingshu 9'. Many StGRF genes exhibited high induction levels in response to R. solanacearum infection and SA treatment while displaying a marked decline in expression in the presence of MeJA. Furthermore, protein interaction network analysis revealed that the StGRF proteins interact with several candidate target proteins, indicating that GRF proteins are ubiquitous regulators in potatoes. However, the associations between two type III effectors (T3Es) RipAC/RipH2 from R. solanacearum isolates and StGRF7 were not detectable in a yeast two-hybrid assay.

Conclusion: This study provides comprehensive information on the GRF gene family and lays a foundation for further research on the molecular mechanism of potato biotic stress adaptation.