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The timely deposition of callose is essential for cytokinesis in Arabidopsis
Author(s) -
Thiele Knut,
Wanner Gerhard,
Kindzierski Viktoria,
Jürgens Gerd,
Mayer Ulrike,
Pachl Fiona,
Assaad Farhah F.
Publication year - 2009
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/j.1365-313x.2008.03760.x
Subject(s) - callose , cell plate , cytokinesis , cell wall , microbiology and biotechnology , biology , arabidopsis , cell division , mutant , botany , cell , genetics , gene
Summary The primary plant cell wall is laid down over a brief period of time during cytokinesis. Initially, a membrane network forms at the equator of a dividing cell. The cross‐wall is then assembled and remodeled within this membrane compartment. Callose is the predominant luminal component of the nascent cross‐wall or cell plate, but is not a component of intact mature cell walls, which are composed primarily of cellulose, pectins and xyloglucans. Widely accepted models postulate that callose comprises a transient, rapid spreading force for the expansion of membrane networks during cytokinesis. In this study, we clone and characterize an Arabidopsis gene, MASSUE / AtGSL8 , which encodes a putative callose synthase. massue mutants are seedling‐lethal and have a striking cytokinesis‐defective phenotype. Callose deposition was delayed in the cell plates of massue mutants. Mutant cells were occasionally bi‐ or multi‐nucleate, with cell‐wall stubs, and we frequently observed gaps at the junction between cross‐walls and parental cell walls. The results suggest that the timely deposition of callose is essential for the completion of plant cytokinesis. Surprisingly, confocal analysis revealed that the cell‐plate membrane compartment forms and expands, seemingly as far as the parental wall, prior to the appearance of callose. We discuss the possibility that callose may be required to establish a lasting connection between the nascent cross‐wall and the parental cell wall.