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Author ORCID Identifier
N/A
AccessType
Open Access Dissertation
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Plant Biology
Year Degree Awarded
2018
Month Degree Awarded
September
First Advisor
Ana Caicedo
Second Advisor
Sam Hazen
Third Advisor
Lynn Adler
Fourth Advisor
Adam Porter
Subject Categories
Evolution | Genetics | Plant Biology
Abstract
As angiosperm seeds mature within their ovaries, ovary tissue tends to grow and transform itself into fruit, which aids the success of the seeds. Fruits that are fleshy provide numerous ways to aid in the protection and the dispersal of seeds. First, they keep seeds hidden, encased in hard walls, surrounded by poisons and unpalatable compounds, and second, they undergo developmental changes that facilitate seeds’ release. Tomatoes, a model fleshy fruit, have all these protective traits, and over the course of ripening they become the familiar fruit that is a staple crop around the world. The wild relatives of cultivated tomatoes, however, have substantial variation in ripening habits. I characterized several fruit traits and their change during ripening in wild tomato species to get a better understanding of the phenotypic variation that exists in fruits. Acquiring this background for the clade enables further investigation of genes behind these variable traits and inferences of how the traits have evolved. To associate fruit traits with genes and genomic regions for further analysis I grew introgression lines (ILs) stemming from introgressions of small portions of the genome of the tomato clade outgroup Solanum lycopersicoides, in the background of the cultivated tomato, S. lycopersicum. With these lines, I found regions of the genome that are associated with change of fruit firmness during ripening, providing data for further investigation of the genetics behind this trait. I also investigated the genetic basis of ripe fruit color variation by characterizing the gene CYC-B, which produces the enzyme responsible for turning red lycopene into the orange β-carotene, across the tomato clade. My results suggest that regulation of CYC-B has been key to the evolution of different fruit colors across the clade, and that the promoter region of the gene is involved in differentiating a β-carotene accumulating plant from a lycopene accumulating plant. The research performed here enhances our understanding of phenotypic and genotypic variation in an understudied angiosperm organ that can alter how plant species interact with animals around them, contributing to our knowledge of how fruit traits evolve and how they can enable plant success.
DOI
https://doi.org/10.7275/12275337
Recommended Citation
Gillis, Ian M., "Variation and Evolution of Fruit Ripening Traits in Tomato Species" (2018). Doctoral Dissertations. 1342.
https://doi.org/10.7275/12275337
https://scholarworks.umass.edu/dissertations_2/1342
Introgression Map
Table S2.xlsx (12 kB)
Sample Count
Table S3.xlsx (13 kB)
Firmness data
Table S4.xlsx (17 kB)
Sugar data
Table S5.xlsx (11 kB)
Correlation Coefficients
Table S6.xlsx (15 kB)
Firmness Gene Map
Table S7.xlsx (15 kB)
Sugar Gene Map
Table S8.xlsx (896 kB)
Complete Microarray Expression Data
Table S9.xlsx (17 kB)
Most Differentially Expressed
Table S10.xlsx (13 kB)
CYC-B Polymorphisms