Characterization of the GGPgene family inpotato (Solanum tuberosum L.) and Capsicum (Capsicum annuum L.) and its expression analysis under hormonal and abiotic stresses

Abstract

Abstract Potato (Solanum tuberosum L.) and capsicum (Capsicum annuum L.) are members of the Solanaceae family, and they are widely grown and used worldwide. However, there are significant differences between these two crops in terms of morphology, growing conditions and resistance to stress. But they share some similarities at a genetic level. GDP-L-galactose phosphorylase (GGP) is a key rate-limiting enzyme in plant ascorbic acid synthesis, which plays an important role in plant growth and development as well as stress response. However, the presence of GGP and its function in potato and capsicum are not known. In this study, we first identified two GGP genes in the potato genome using a genome-wide search approach. Similarly, two GGP genes were identified in the capsicum genome. We then analyzed their physicochemical properties, conserved domains, protein structures and phylogenetic relationships. Phylogenetic tree analysis revealed that members of the potato and capsicum GGP gene families are related to cabbage(Brassica campestris), Arabidopsis (Arabidopsis thaliana L.), apple (Malus domestica cv. Gala) and tomato (Solanum lycopersicum L.), with tomato being the most closely related. The promoter sequences mainly contain homeopathic elements such as light-responsive, hormone-responsive and stress-responsive, with light-responsive elements being the most abundant. By analyzing the structure of the genes, it was found that there is no transmembrane structure or signal peptide in the GGP gene family of potatoes and capsicums, and that all of its members are hydrophilic proteins. The expression profiles of the different tissues showed that the potato GGPwas more highly expressed in the leaves and the capsicum GGP was more highly expressed in the fruits. qRT-PCR analysis showed that the GGPgene was responsive to both ABA and MeJA in both the potato and the capsicum. In addition, the GGP genes in both the potato and the capsicum showed different responses to darkness stress, cold stress, salt stress and drought stress. Based on our experimental findings, it is evident that StGGPsprimarily respond to dark stress, while CaGGPs primarily respond to NaCl stress. This study provides a basis for a better understanding of the role of GGP-homologous genes from potato and capsicum in the response of plants to abiotic stress, and lays the foundation for further research into the role of GGPs in plants.