Natural Variation in Leaf Morphology Results from Mutation of a Novel KNOX Gene

Striking diversity in size, arrangement, and complexity of leaves can sometimes be seen in closely related species. One such variation is found between wild tomato species collected by Charles Darwin from the Galapagos Islands [1–5]. Here, we show that a single-nucleotide deletion in the promoter of...

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Bibliographic Details
Published in:Current biology 2008-05, Vol.18 (9), p.672-677
Main Authors: Kimura, Seisuke, Koenig, Daniel, Kang, Julie, Yoong, Fei Yian, Sinha, Neelima
Format: Article
Language:English
Subjects:
Cloning, Molecular
DNA
EVO_ECOL
Homeodomain Proteins - genetics
Homeodomain Proteins - metabolism
Lycopersicon esculentum
Molecular Sequence Data
Mutation
Petroselinum
Phenotype
Plant Leaves - anatomy & histology
Plant Proteins - genetics
Plant Proteins - metabolism
Polymorphism, Single Nucleotide
Protein Structure, Tertiary
Solanum - anatomy & histology
Solanum - genetics
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Summary:Striking diversity in size, arrangement, and complexity of leaves can sometimes be seen in closely related species. One such variation is found between wild tomato species collected by Charles Darwin from the Galapagos Islands [1–5]. Here, we show that a single-nucleotide deletion in the promoter of the PETROSELINUM (PTS) [3] gene upregulates the gene product in leaves and is responsible for the natural variation in leaf shape in the Galapagean tomatoes. PTS encodes a novel KNOTTED1-LIKE HOMEOBOX (KNOX) gene that lacks a homeodomain. We also showed that the tomato classical mutant bipinnata (bip) [6], which recapitulates the Pts phenotype, results from the loss of function of a BEL-LIKE HOMEODOMAIN (BELL) gene, BIP. We used bimolecular fluorescence complementation and two-hybrid competition assays to show that PTS represses KNOX1 protein interactions with BIP, as well as subsequent nuclear localization of this transcriptional complex. We suggest that natural variation in leaf shape can be created with a rheostat-like mechanism that alters the KNOX1 protein interaction network specifically during leaf development. This subtle change in interaction between transcription factors leaves essential KNOX1 function in the shoot apical meristem intact and appears to be a facile way to alter leaf morphology during evolution.
ISSN:0960-9822
1879-0445
DOI:10.1016/j.cub.2008.04.008