Complex cellular and molecular events determining fruit size

The tomato fruit provides a valuable model for studying the mechanisms underlying size control in agronomically important organs. Final fruit size is a complex trait that results from a strict spatial and temporal control and coordination of overlapping and interconnected cellular events, cell division, and cell expansion, occurring with different onsets, rates, and duration. Genes regulating tomato fruit size influence cell division or expansion and can act at different periods from ovary development until the onset of ripening. The understanding of plant organ-size determination represents an important challenge, especially because of the significant role of plants as food and renewable energy sources and the increasing need for plant-derived products. Most of the knowledge on the regulation of organ growth and the molecular network controlling cell division and cell expansion, the main drivers of growth, is derived from arabidopsis. The increasing use of crops such as tomato for research is now bringing essential information on the mechanisms underlying size control in agronomically important organs. This review describes our current knowledge, still very scarce, of the cellular and molecular mechanisms governing tomato fruit size and proposes future research to better understand the regulation of growth in this important crop. The understanding of plant organ-size determination represents an important challenge, especially because of the significant role of plants as food and renewable energy sources and the increasing need for plant-derived products. Most of the knowledge on the regulation of organ growth and the molecular network controlling cell division and cell expansion, the main drivers of growth, is derived from arabidopsis. The increasing use of crops such as tomato for research is now bringing essential information on the mechanisms underlying size control in agronomically important organs. This review describes our current knowledge, still very scarce, of the cellular and molecular mechanisms governing tomato fruit size and proposes future research to better understand the regulation of growth in this important crop.