Genome-Wide Characterization of the PIFs Family in Sweet Potato and Functional Identification of IbPIF3.1 under Drought and Fusarium Wilt Stresses

Phytochrome-interacting factors (PIFs) are essential for plant growth, development, and defense responses. However, research on the in sweet potato has been insufficient to date. In this study, we identified genes in the cultivated hexaploid sweet potato ( ) and its two wild relatives, , and . Phylogenetic analysis revealed that IbPIFs could be divided into four groups, showing the closest relationship with tomato and potato. Subsequently, the PIFs protein properties, chromosome location, gene structure, and protein interaction network were systematically analyzed. RNA-Seq and qRT-PCR analyses showed that were mainly expressed in stem, as well as had different gene expression patterns in response to various stresses. Among them, the expression of was strongly induced by salt, drought, H O , cold, heat, f. sp. ( ), and stem nematodes, indicating that might play an important role in response to abiotic and biotic stresses in sweet potato. Further research revealed that overexpression of .1 significantly enhanced drought and wilt tolerance in transgenic tobacco plants. This study provides new insights for understanding PIF-mediated stress responses and lays a foundation for future investigation of sweet potato PIFs.