Underlying mechanisms of diversity in tomato fruit morphology

VAN DER KNAAP, ESTHER; RODRÍGUEZ, GUSTAVO RUBÉN; XIAO, HAN

Cologne, Alemania

Workshop; The 5th Solanaceae Genome Workshop 2008; 2008

Sol Genomics Network

The domestication of tomato (Solanum lycopersicum) resulted in many varieties that differ in fruit morphology. In recent years, the underlying molecular basis for the fruit diversity is being unraveled. This information is critical to gain insights into the domestication of tomato while also improving the understanding of the regulation of fruit shape and patterning. To date, the identity of four genes that control tomato fruit morphology is known. FW2.2 controls fruit mass, FASCIATED (FAS) controls locule number and fruit mass, whereas OVATE and SUN control fruit elongation. We recently cloned SUN and found that the locus arose in a highly unusual gene duplication event1. SUN controls elongated fruit shape by increasing fruit length and reducing fruit width, and its effect is most strongly exhibited after fertilization. The effect of SUN on fruit morphology is to increase the oval shape of the seed part of the fruit. The gene encodes a member of the IQ domain family of proteins which have been hypothesized to regulate hormone and/or secondary metabolism levels1. Contrary to SUN, OVATE exhibits its most dramatic effect on fruit shape prior to fertilization2. The largest effect of OVATE is on the eccentric positioning of the seed in the fruit. A significant part of the fruit shape variation present in the cultivated tomato germplasm is attributed to either SUN or OVATE. 1. Xiao et al, 2008. Science 319: 1527. Funded by NSF DBI 0227541.