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Biology Program presents

How to Make a Tomato: Comparative Fruit Development in the Nightshade Family

Thursday, November 14, 2013

[How to Make a Tomato: Comparative Fruit Development in the Nightshade Family]
A lecture by
Amy Litt
Candidate for the position in Biology

Fleshy, edible fruit have evolved from dry fruit in many flowering plant families, with important economic and ecological consequences.   In the nightshade family (Solanaceae), many species produce dry, woody fruits (capsules) that split open at maturity to release their seeds, but a large group that includes tomato, potato, eggplant, and pepper produces fleshy fruit (berries) that are eaten by animals who disperse the seeds.  We are interested in the developmental and genetic changes that led to the evolution of the berry.  In both fruit types, development includes a phase of extensive cell division followed by cell differentiation and then ripening or maturation, although the specific patterns and processes differ.  Comparative transcriptome analyses of tomatoes and desert tobacco capsules during the stage of cell division provided a list of hundreds of genes that appear to be acting differently in the two fruit types.  We studied one of these, FRUITFULL (FUL), to determine whether it plays a role in berry and capsule formation in Solanaceae.  Our analyses show that whereas species with fleshy fruits, such as tomato, have four copies of this gene, species with dry capsular fruits have only three.  In tomato one of these genes, FUL2, controls a wide variety of traits including fruit size, shape, and color.  Notably, it is important in determining the thickness of the tomato fruit wall, a key feature that distinguishes berries and capsules.  In contrast, FUL2 appears to have no effect on desert tobacco capsule development.  Our results suggest that changes in the number and function of FUL genes might have played an important role in the evolutionary origin of fleshy fruit.

Location: Reem-Kayden Center Laszlo Z. Bito '60 Auditorium