Genome-Wide Identification, Expression Patterns and Sugar Transport of the Physic Nut Gene Family and a Functional Analysis of in .

The Sugars Will Eventually be Exported Transporters (SWEET) family is a class of sugar transporters that play key roles in phloem loading, seed filling, pollen development and the stress response in plants. Here, a total of 18 genes were identified in physic nut ( L.) and classified into four clades by phylogenetic analysis. These genes share similar gene structures, and alternative splicing of messenger RNAs was observed for five of the genes. Three (//) of the JcSWEETs were found to possess transport activity for hexose molecules in yeast. Real-time quantitative PCR analysis of in different tissues under normal growth conditions and abiotic stresses revealed that most are tissue-specifically expressed, and 12 responded to either drought or salinity. The gene responded to drought and salinity stress in leaves, and the protein it encodes is localized in both the plasma membrane and the vacuolar membrane. The overexpression of in modified the flowering time and saline tolerance levels but not the drought tolerance of the transgenic plants. Together, these results provide insights into the characteristics of genes in physic nut and could serve as a basis for cloning and further functional analysis of these genes.