Sucrose Transporter Gene AtSUC4 Regulates Sucrose Distribution and Metabolism in Response to Salt Stress in Arabidopsis Thaliana

Sporadic reports indicated that salt stress induced the expression of sucrose transporter genes, and sucrose transporters (SUCs or SUTs) as the important carriers are responsible for the loading, unloading and distribution of sucrose, but the study that SUCs are involved in sucrose distribution and metabolism under salt stress at the whole-plant level has not been reported to date. AtSUC4, as the unique member of low affinity/high capacity SUT4-clade in Arabidopsis thaliana, may play an important role in plant stress tolerance. Here, through analyzing two homozygous mutation lines of AtSUC4 (Atsuc4-1 and Atsuc4-2), we found salt stress induced higher sucrose, fructose and glucose content in shoots and lower sucrose, fructose and glucose content in roots of these mutants compared with the wild-type (WT), resulting in an imbalance of sucrose distribution and fructose and glucose accumulation changes of sucrose metabolites at the-whole-plant level. Our results indicated that AtSUC4 is involved in salt stress tolerance by the regulation of sucrose distribution and metabolism.