Functional conservation and maintenance of expression pattern of FIDDLEHEAD-like genes in Arabidopsis and Antirrhinum.
In Arabidopsis, loss of function of the epidermis-specific FDH gene coding for a putative beta-ketoacyl-CoA synthase results in ectopic organ fusions in mutants. Corresponding mutants are not available for Antirrhinum majus, however, organ fusions can be induced in both species by chloroacetamide inhibitors of beta-ketoacyl-CoA synthases using a chemical genetics approach. We isolated the ortholog of FDH from Antirrhinum majus, the ANTIRRHINUM FIDDLEHEAD (AFI ) gene, and showed that AFI complements fdh when expressed in the epidermis under control of the FDH promoter. Like FDH, the AFI gene exhibits protodermis- and epidermis-specific expression, and its promoter directs the expression of reporter genes to the epidermis in transgenic Antirrhinum and Arabidopsis. We demonstrate down-regulation of the FDH promoter in the epidermis of the ovary septum, thereby supporting the assumption that FDH-like genes may directly facilitate the cell-cell interactions that need to occur during carpel fusion and pollen tube growth. Up-regulation of FDH in the stomium, on the other hand, provides evidence for its possible involvement in cell separation during anther dehiscence. Down-regulation of the FDH and AFI promoters in the septum is observed in transgenic Arabidopsis but not in Antirrhinum plants. This probably reflects differences in the ontogeny of the ovary septum between the two species. We also show that epidermis-specific FDH-like genes may not be able to efficiently elongate fatty acid chains when misexpressed in seeds.
Efremova
Nadia
N
Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
Schreiber
Lukas
L
Bär
Sascha
S
Heidmann
Iris
I
Huijser
Peter
P
Wellesen
Kirsten
K
Schwarz-Sommer
Zsuzsanna
Z
Saedler
Heinz
H
Yephremov
Alexander
A
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000037:antagonists & inhibitors; D000081:Acetamides / Q000494:pharmacology; D032161:Antirrhinum / Q000235:genetics* / Q000254:growth & development; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D019441:Plant Epidermis / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000235:genetics
D000081:Acetamides; D029681:Arabidopsis Proteins; C402598:At2g26250 protein, Arabidopsis; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; C013874:chloroacetamide; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D005966:Glucuronidase