Development

When MADS, Don't Throw Tomatoes

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Science  11 Aug 2006:
Vol. 313, Issue 5788, pp. 735
DOI: 10.1126/science.313.5788.735a

Two types of MADS-box APETALA3 (AP3) genes are found in members of the tomato family of plants: the euAP3 group, which is critical for the proper development of the petals and stamens in angiosperms, and the less well-understood TM6 group. Petunia hybrida and tomato (Solanum lycopersicum) each have a euAP3 gene (PhDEF and TAP3, respectively) and a TM6 gene (PhTM6 and TM6). The euAP3 and TM6 lineages are hypothesized to have originated through a gene duplication event before the diversification of the major core eudicot lineages approximately 125 million years ago.

Rijpkema et al. and de Martino et al. have analyzed petunia and tomato mutants and found that in both species, euAP3 genes maintain petal and stamen identity, whereas TM6 genes function redundantly with euAP3 genes in stamen development. Ectopic expression of TM6 genes in euAP3 lack-of-function mutants demonstrates that TM6 genes are functionally redundant in both petal and stamen development. Rijpkema et al. also examined the promoter regions of euAP3 and TM6 regulatory sequences and found distinct yet highly conserved regions among euAP3 core eudicot genes as well as in tomato and petunia TM6 genes. Despite these similarities, the differences in expression and function between tomato and petunia TM6 genes suggest that these genes have diversified functionally over a relatively short evolutionary time of 40 million years. — LMZ

Plant Cell 18, 10.1105/tpc.106.042937; 10.1105/tpc.106.042978 (2006).

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