Parthenocarpic apple fruit production conferred by transposon insertion mutations in a MADS-box transcription factor
Fruit development in higher plants normally requires pollination and fertilization to stimulate cell division of specific floral tissues. In some cases, parthenocarpic fruit development proceeds without either pollination or fertilization. Parthenocarpic fruit without seed has higher commercial valu...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 98; no. 3; pp. 1306 - 1311 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
30.01.2001
|
Online Access | Get full text |
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Summary: | Fruit development in higher plants normally requires pollination and fertilization to stimulate cell division of specific floral tissues. In some cases, parthenocarpic fruit development proceeds without either pollination or fertilization. Parthenocarpic fruit without seed has higher commercial value than seeded fruit. Several apple (
Malus domestica
) mutants (Rae Ime, Spencer Seedless and Wellington Bloomless) are known to produce only apetalous flowers that readily go on to develop into parthenocarpic fruit. Through genetics, a single recessive gene has been identified to control this trait in apple. Flower phenotypes of these apple mutants are strikingly similar to those of the
Arabidopsis
mutant
pistillata
(
pi
), which produces flowers where petals are transformed to sepals and stamens to carpels. In this study, we have cloned the apple
PI
homolog (
MdPI
) that shows 64% amino acid sequence identity and closely conserved intron positions and mRNA expression patterns to the
Arabidopsis PI
. We have identified that in the apetalous mutants
MdPI
has been mutated by a retrotransposon insertion in intron 4 in the case of Rae Ime and in intron 6 in the case of Spencer Seedless and Wellington Bloomless. The insertion apparently abolishes the normal expression of the
MdPI
gene. We conclude that the loss of function mutation in the
MdPI
MADS-box transcription factor confers parthenocarpic fruit development in these apple varieties and demonstrates another function for the MADS- box gene family. The knowledge generated here could be used to produce parthenocarpic fruit cultivars through genetic engineering. |
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ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.98.3.1306 |