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The WOX 13 homeobox gene promotes replum formation in the Arabidopsis thaliana fruit
Author(s) -
RomeraBranchat Maida,
Ripoll Juan José,
Yanofsky Martin F.,
Pelaz Soraya
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12010
Subject(s) - meristem , homeobox , biology , arabidopsis , mutant , arabidopsis thaliana , microbiology and biotechnology , gynoecium , dlx5 , gene , phenotype , genetics , botany , transcription factor , pollen , stamen
Summary The Arabidopsis fruit forms a seedpod that develops from the fertilized gynoecium. It is mainly comprised of an ovary in which three distinct tissues can be differentiated: the valves, the valve margins and the replum. Separation of cells at the valve margin allows for the valves to detach from the replum and thus dispersal of the seeds. Valves and valve margins are located in lateral positions whereas the replum is positioned medially and retains meristematic properties resembling the shoot apical meristem ( SAM ). Members of the WUSCHEL ‐related homeobox family have been involved in stem cell maintenance in the SAM , and within this family, we found that WOX 13 is expressed mainly in meristematic tissues including the replum. We also show that wox13 loss‐of‐function mutations reduce replum size and enhance the phenotypes of mutants affected in the replum identity gene RPL . Conversely, misexpression of WOX 13 produces, independently from BP and RPL , an oversized replum and valve defects that closely resemble those of mutants in JAG / FIL activity genes. Our results suggest that WOX 13 promotes replum development by likely preventing the activity of the JAG / FIL genes in medial tissues. This regulation seems to play a role in establishing the gradient of JAG / FIL activity along the medio‐lateral axis of the fruit critical for proper patterning. Our data have allowed us to incorporate the role of WOX 13 into the regulatory network that orchestrates fruit patterning.