RT Journal Article SR Electronic T1 Overexpression of a Gene Encoding a Cytochrome P450, CYP78A9, Induces Large and Seedless Fruit in Arabidopsis JF The Plant Cell JO Plant Cell FD American Society of Plant Biologists SP 1541 OP 1550 DO 10.1105/tpc.12.9.1541 VO 12 IS 9 A1 Ito, Toshiro A1 Meyerowitz, Elliot M. YR 2000 UL http://www.plantcell.org/content/12/9/1541.abstract AB An activation tagging screen in which the cauliflower mosaic virus 35S enhancer was inserted randomly into an Arabidopsis genome homozygous for the floral homeotic mutation apetala2-1 (ap2-1) resulted in a line (28-5) with extraordinarily wide, heart-shaped ovaries. The ovary of the 28-5 ap2-1 mutant shows an oval shape because of increased numbers of enlarged cells. When the ap2-1 mutation is crossed out of the genetic background, more elongated rather than wider fruits are obtained. Normally, Arabidopsis fruits will develop to a normal size only when the ovules are present and fertilized. In the 28-5 single mutant, the siliques keep growing despite failure of fertilization and can reach nearly normal size. When wild-type pollen was used to pollinate the mutant pistil, the pollinated 28-5 silique became >10% longer and 40% wider than a wild-type silique, although producing very few seeds. The enhancer insertion in line 28-5 acts by hyperactivating a cytochrome P450 gene, CYP78A9. The pistil of 28-5 ap2-1 mutant flowers shows a structure similar to that of Capsella bursa-pastoris, a distant mustard relative of Arabidopsis, suggesting that the processes regulated by the CYP78A9-encoded protein may be involved in evolutionary control of carpel shape.