**5. Conclusions**

The *Solanaceae* genus is one of the most morphologically various plant families, with more than 3000 described species being distributed worldwide [60]. Apart from being of economic value, tomato is also a model crop for fleshy fruit development [35,61]. In addition, tomato is still the first horticultural crop for which its genome has been sequenced [62]. In this study, we identified nine *SlUGlcAE* genes and analyzed the spatiotemporal expression patterns, the phylogenetic relationships, the selective pressure, the *cis*-acting elements, and so on. We also focused on the response patterns of nine *SlUGlcAE* genes to IAA, GA, and SA, according to the results of *cis*-acting elements analysis. Moreover, the firmness decreased gradually, and WSP showed an increased trend, reached a maximum at the MG stage, and then decreased in the development of tomato fruit. All of the results above have allowed for us to identify tomato orthologs that are related to known *UGlcAE* genes in *Arabidopsis* for in-depth studies. It would also accelerate for executing functional studies based genomics to elucidate their elaborate roles in tomato fruit development, and to be helpful for revealing the roles of other members in the *Solanaceae* genus.

**Supplementary Materials:** Supplementary materials can be found at http://www.mdpi.com/1422-0067/19/6/ 1583/s1.

**Author Contributions:** X.Z., X.D. conceived and designed the study; X.D. collected data, processed and analyzed the data, created the figures, wrote the manuscript and completed the submission; J.L. and Y.P. helped design the experiments, provided the research facility and helped write the manuscript; Y.Z., L.N. and Y.W. provided daily care to the plant and helped collect plant leaves at different times.

**Acknowledgments:** This work was supported by the National High Technology Research and Development Program of China (863 Program, Grant no. 2010AA10060705).

**Conflicts of Interest:** The authors declare no conflict of interest.
