Interplay of MYB factors in differential cell expansion, and consequences for tomato fruit development.

We previously identified SlFSM1 as an early fruit-specific gene encoding a short protein harboring a non-canonical SANT/MYB-like domain. Here, we investigated the role of FSM1 during fruit development in tomato and its mode of action. By analyzing tomato plants ectopically expressing FSM1, we established that it negatively affects cell expansion, particularly of those cells with the highest potential to expand, such as those residing inner to the vascular bundles in the fruit pericarp.

The tomato early fruit specific gene Lefsm1 defines a novel class of plant-specific SANT/MYB domain proteins.

We describe here a novel plant-specific gene, Lefsm1 (fruit SANT/MYB-like 1) harboring a single SANT/MYB domain. The expression of Lefsm1 is specific to the very early stages of tomato (Lycopersicon esculentum) fruit development. Ectopic expression of Lefsm1 results in severe developmental alterations manifested in retarded growth, and reduced apical dominance during tomato and Arabidopsis seedling development.