Genome-wide identification of the SWEET gene family in Phaseolus vulgaris L. and their patterns of expression under abiotic stress

Sugar Will Eventually be Exported Transporters (SWEET) proteins function as sugar transporters that play key roles in plant growth, development, and biotic and abiotic stress responses. However, little is known about the SWEET gene family in common bean (Phaseolus vulgaris L.). In this study, 24 putative PvSWEET genes were identified. They can be categorized into four subgroups based on a phylogenetic analysis, exon-intron structure, cis-regulatory elements, and MEME motifs. A collinearity analysis showed that three pairs of segmental duplicated events were identified. The Phytozome database showed that 16 PvSWEET genes were highly expressed in reproductive organs. PvSWEET5 was expressed the most highly in all the tissues tested, while PvSWEET8/9/10/13 were undetectable in the datasets. The results of qRT-PCR analysis showed that PvSWEET24 was significantly up-regulated following treatment with NaCl, CdCl2, and HgCl2, whereas the PvSWEET5 and PvSWEET20 genes displayed a specific negative response to CdCl2 stress. Collectively, this study provides comprehensive information for the role of SWEET gene family in common bean and lays a solid foundation to elucidate the biological function of the PvSWEET gene family, as well as provide insights into the correlation between the PvSWEET genes and responses to metal stresses.