Apple SVP Family MADS-Box Proteins and the Tomato Pedicel Abscission Zone Regulator JOINTLESS have Similar Molecular Activities.
Pedicel abscission occurs widely in fruit-bearing plants to detach ripe, senescent or diseased organs, and regulation of abscission plays a substantial role in regulating yield and quality in fruit crops. In tomato, development of pedicel abscission zones (AZs) requires the MADS-box genes JOINTLESS (J), MACROCALYX (MC) and SlMBP21. In other plants, however, the involvement of MADS-box genes in pedicel abscission remains unclear. Here, we used genetic and biochemical methods to characterize apple J homologs in the context of the regulation of abscission in tomato. We identified three genes encoding two J homologs, MdJa and MdJb. Similarly to J, MdJa and MdJb interacted with MC and SlMBP21, but their interactions differed slightly: like J, MdJb formed a multimer (probably a tetramer) with SlMBP21; however, MdJa formed multimers to a lesser extent. Ectopic expression of MdJb in a J-deficient tomato mutant restored development of functional pedicel AZs, but ectopic expression of MdJa did not complement j mutants. Introduction of MdJb also restored expression of J-dependent genes in the mutant, such as genes for polygalacturonase, cellulase and AZ-specific transcription factors. These results suggest a potentially conserved mechanism of pedicel AZ development in apple and other plants, regulated by MADS-box transcription factors.
National Food Research Institute, NARO, Ibaraki, 305-8642 Japan Present address: Institute of Crops Research and Development, Vietnam National University of Agriculture, Hanoi, Vietnam.
Toshitsugu
T
Nakano
National Food Research Institute, NARO, Ibaraki, 305-8642 Japan Department of Applied Biological Science, Tokyo University of Science, Chiba, 278-8510 Japan.
Hiroki
H
Kato
National Food Research Institute, NARO, Ibaraki, 305-8642 Japan.
Yoko
Y
Shima
National Food Research Institute, NARO, Ibaraki, 305-8642 Japan yasuito@affrc.go.jp.
Yasuhiro
Y
Ito
D015536:Down-Regulation / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D035264:Flowers / Q000378:metabolism; D005638:Fruit / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005810:Multigene Family; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D020798:Two-Hybrid System Techniques
D026161:MADS Domain Proteins; D010940:Plant Proteins
Abscission; Apple; JOINTLESS; MADS-box; Tomato