Natural Alleles at a Tomato Fruit Size Quantitative Trait Locus Differ by Heterochronic Regulatory Mutations

fw2.2 is a major quantitative trait locus that accounts for as much as 30% of the difference in fruit size between wild and cultivated tomatoes. Evidence thus far indicates that fw2.2 alleles modulate fruit size through changes in gene regulation rather than in the FW2.2 protein itself. To investiga...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2002-10, Vol.99 (21), p.13606-13611
Main Authors: Cong, Bin, Liu, Jiping, Tanksley, Steven D.
Format: Article
Language:English
Subjects:
Alleles
Biological Evolution
Biological Sciences
Cell Count
Cell division
Cell growth
Cell Size
Evolution
Flowering
Fruiting
Fruits
Gene Expression Regulation, Developmental
Gene Expression Regulation, Plant
Genes, Plant
Genetic mutation
Genetic Variation
Lycopersicon esculentum - genetics
Lycopersicon esculentum - growth & development
Lycopersicon esculentum - metabolism
Mitotic Index
Mutation
Pericarp
Phenotype
Placenta
Plant growth
Quantitative Trait Loci
RNA
RNA, Messenger - genetics
RNA, Messenger - metabolism
RNA, Plant - genetics
RNA, Plant - metabolism
Tomatoes
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Summary:fw2.2 is a major quantitative trait locus that accounts for as much as 30% of the difference in fruit size between wild and cultivated tomatoes. Evidence thus far indicates that fw2.2 alleles modulate fruit size through changes in gene regulation rather than in the FW2.2 protein itself. To investigate the nature of these regulatory changes and the manner in which they may affect fruit size, a pair of nearly isogenic lines has been subjected to detailed developmental, transcriptional, mitotic, and in situ hybridization studies. The results indicate that the large- and small-fruited alleles of fw2.2 differ in peak transcript levels by ≈1 week. Moreover, this difference in timing of expression is associated with concomitant changes in mitotic activity in the early stage of fruit development. The changes in timing of gene expression (heterochronic allelic variation), combined with overall differences in total transcript levels, are sufficient to account for a large portion phenotypic differences in fruit weight associated with the two alleles.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.172520999