title: MACROCALYX and JOINTLESS interact in the transcriptional regulation of tomato fruit abscission zone development.
abstract: Abscission in plants is a crucial process used to shed organs such as leaves, flowers, and fruits when they are senescent, damaged, or mature. Abscission occurs at predetermined positions called abscission zones (AZs). Although the regulation of fruit abscission is essential for agriculture, the developmental mechanisms remain unclear. Here, we describe a novel transcription factor regulating the development of tomato (Solanum lycopersicum) pedicel AZs. We found that the development of tomato pedicel AZs requires the gene MACROCALYX (MC), which was previously identified as a sepal size regulator and encodes a MADS-box transcription factor. MC has significant sequence similarity to Arabidopsis (Arabidopsis thaliana) FRUITFULL, which is involved in the regulation of fruit dehiscent zone development. The MC protein interacted physically with another MADS-box protein, JOINTLESS, which is known as a regulator of fruit abscission; the resulting heterodimer acquired a specific DNA-binding activity. Transcriptome analyses of pedicels at the preabscission stage revealed that the expression of the genes involved in phytohormone-related functions, cell wall modifications, fatty acid metabolism, and transcription factors is regulated by MC and JOINTLESS. The regulated genes include homologs of Arabidopsis WUSCHEL, REGULATOR OF AXILLARY MERISTEMS, CUP-SHAPED COTYLEDON, and LATERAL SUPPRESSOR. These Arabidopsis genes encode well-characterized transcription factors regulating meristem maintenance, axillary meristem development, and boundary formation in plant tissues. The tomato homologs were specifically expressed in AZs but not in other pedicel tissues, suggesting that these transcription factors may play key roles in pedicel AZ development.
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors: Toshitsugu
authors: T
authors: Nakano
authors: Junji
authors: J
authors: Kimbara
authors: Masaki
authors: M
authors: Fujisawa
authors: Mamiko
authors: M
authors: Kitagawa
authors: Nao
authors: N
authors: Ihashi
authors: Hideo
authors: H
authors: Maeda
authors: Takafumi
authors: T
authors: Kasumi
authors: Yasuhiro
authors: Y
authors: Ito
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics; D005638:Fruit / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics; D018551:Solanum lycopersicum / Q000502:physiology*; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome
chemical_list: C097414:AGL8 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C118233:J protein, Lycopersicon esculentum; D026161:MADS Domain Proteins; D010940:Plant Proteins; D014157:Transcription Factors; C116421:WUSCHEL protein, Arabidopsis