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TUMOROUS SHOOT DEVELOPMENT (TSD) genes are required for co‐ordinated plant shoot development
Author(s) -
Frank Markus,
Guivarc'h Anne,
Krupková Eva,
LorenzMeyer Irina,
Chriqui Dominique,
Schmülling Thomas
Publication year - 2002
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 - 10.1046/j.1365-313x.2002.01197.x
Subject(s) - meristem , biology , mutant , cytokinin , arabidopsis , shoot , gene , microbiology and biotechnology , auxin , complementation , cell division , apical dominance , homeobox , primordium , genetics , arabidopsis thaliana , botany , gene expression , cell
Summary This report describes the identification of novel plant genes that are required to ensure co‐ordinated post‐embryonic development. After germination the tumorous shoot development mutants of Arabidopsis thaliana develop disorganized tumorous tissue instead of organized leaves and stems. This results in green callus‐like structures, which are capable of unlimited growth in vitro on hormone‐free medium. The tsd mutants are recessive and belong to three complementation groups ( tsd1, tsd2, tsd3 ). The genes were mapped to the bottom of chromosomes 5 and 1, and the top of chromosome 3, respectively. Histological analyses showed that the tsd mutants have different developmental defects. The shoot apical meristem of tsd1 formed only rudimentary leaves and was characterized by a degenerating L1 cell layer. tsd2 mutants had reduced cell adhesion and altered cell division planes in the L2 and L3 cell layers. The tumorous tissue of tsd3 mutants originated from the base of the leaf. Cytokinin levels that are inhibitory to the growth of wild‐type seedlings bring about an enhanced growth response in all the tsd mutants. The steady state transcript levels of the histidine kinase CKI1 gene and the KNAT1 and STM homeobox genes were increased in tsd mutants, while mRNA levels of cell cycle genes were not altered. We hypothesize that the TSD gene products negatively regulate cytokinin‐dependent meristematic activity during vegetative development of Arabidopsis .