Abstract Detail



Applications of Plant Genomics

Rajewski, Alex [1], Maheepala, Dinusha [2], Henry, Ashley [3], Elkins, Kevan [4], Litt, Amy [5].

Comparative transcriptome profiling of dry and fleshy fruit development.

Among angiosperms, the evolutionary transition from ancestral dry fruits to derived fleshy fruits has occurred many times and often has had profound ecological and economic ramifications. In the family Solanaceae, the origin of the subfamily Solanoideae is correlated with such a fruit type transition. Previous work in this family has established that changes in pericarp cell division, expansion, and differentiation across fruit development contribute to the morphological differences between the fruit types. Following fertilization, dry fruit pericarps undergo rapid cell division in the anticlinal orientation, while in fleshy fruits this happens in both anticlinal and periclinal orientations, establishing such morphological differences early on in development. The subsequent stages for dry fruit are the lignification of cell walls followed by drying. In place of a pericarp-wide lignification, fleshy fruit exhibit endoreduplication-related cellular expansion, leading to fruit maturation and ripening. To begin to understand the genetic basis of the transition from dry to fleshy fruit, we have performed RNA-seq on a developmental series of pericarps from dry-fruited desert tobacco (Nicotiana obtusifolia), a small, profusely flowering diploid congener of N. tabacum, as well as cultivated tomato, Solanum lycopersicum, and its closest wild relative, S. pimpinellifolium. Our analyses show an enrichment of functional categories that are correlated with the  morphological and developmental similarities and differences observed between developmental stages within a species or between the corresponding developmental stages between species. For instance, following fertilization, both fruit types undergo extensive cytokinesis, resulting in a growth spurt. Later in development, other cellular processes such as ethylene biosynthesis related to ripening or lignification related to drying become dominant depending on the fruit type.  The results of this study also allow us to construct gene coexpression networks and to identify suites of genes showing similar expression patterns, which might represent regulatory modules that distinguish the two fruit types. These regulatory modules will allow us to look for conservation in the genetic regulation of fruit development in other species with different histories of fruit evolution. Within Solanaceae, Datura spp. have reverted from a fleshy berry to a dry capsule, and Cestrum spp. have an independent origin of fleshy fruits, but our results can also be extended to similar fruit-type transitions in other plant groups.


1 - UC Riverside, Botany And Plant Science, 900 University Ave, Batchelor Hall, Riverside, CA, 92521, United States
2 - University Of California, Botany And Plant Sciences, 3149 Batchelor Hall, Riverside, CA, 92521, United States
3 - University of Wisconsin, Madison, Madison, WI
4 - University of California, Riverside, 900 University Avenue, Department of Botany and Plant Sciences, Riverside, CA, 92521, United States
5 - University Of California, Riverside, Botany And Plant Sciences, 900 University Avenue, Riverside, CA, 92521, United States

Keywords:
fruit
tomato
tobacco
Evolution
Solanaceae.

Presentation Type: Colloquium Presentations
Number:
Abstract ID:729
Candidate for Awards:None


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