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Trehalose-6-phosphate (T6P) phosphatase (TPP), a dephosphorylating enzyme, catalyzes the dephosphorylation of T6P, generating trehalose. In <i>Jatropha</i>, we found six members of the <i>TPP</i> family. Five of them <i>JcTPPA</i>, <i>JcTPPC</i>, <i>JcTPPD</i>, <i>JcTPPG</i>, and <i>JcTPPJ</i> are highly expressed in female flowers or male flowers, or both, suggesting that members of the <i>JcTPP</i> family may participate in flower development in <i>Jatropha</i>. The wide expression of <i>JcTPPJ</i> gene in various organs implied its versatile roles and thus was chosen for unraveling its biological functions during developmental process. We constructed an overexpression vector of <i>JcTPPJ</i> cDNA driven by the cauliflower mosaic virus (CaMV) 35S promoter for genetic transformation. Compared with control <i>Arabidopsis</i> plants, <i>35S:JcTPPJ</i> transgenic <i>Arabidopsis</i> plants presented greater sucrose contents in their inflorescences and displayed late-flowering and heterostylous phenotypes. Exogenous application of sucrose to the inflorescence buds of wild-type <i>Arabidopsis</i> repressed the development of the perianth and filaments, with a phenocopy of the <i>35S:JcTPPJ</i> transgenic <i>Arabidopsis</i>. These results suggested that the significantly increased sucrose level in the inflorescence caused (or induced) by <i>JcTTPJ</i> overexpression, was responsible for the formation of heterostylous flower phenotype. However, <i>35S:JcTPPJ</i> transgenic <i>Jatropha</i> displayed no obvious phenotypic changes, implying that <i>JcTPPJ</i> alone may not be sufficient for regulating flower development in <i>Jatropha</i>. Our results are helpful for understanding the function of <i>TPPs</i>, which may regulate flower organ development by manipulating the sucrose status in plants.