The Arabidopsis callose synthase gene GSL8 is required for cytokinesis and cell patterning.
Cytokinesis is the division of the cytoplasm and its separation into two daughter cells. Cell plate growth and cytokinesis appear to require callose, but direct functional evidence is still lacking. To determine the role of callose and its synthesis during cytokinesis, we identified and characterized mutants in many members of the GLUCAN SYNTHASE-LIKE (GSL; or CALLOSE SYNTHASE) gene family in Arabidopsis (Arabidopsis thaliana). Most gsl mutants (gsl1-gsl7, gsl9, gsl11, and gsl12) exhibited roughly normal seedling growth and development. However, mutations in GSL8, which were previously reported to be gametophytic lethal, were found to produce seedlings with pleiotropic defects during embryogenesis and early vegetative growth. We found cell wall stubs, two nuclei in one cell, and other defects in cell division in homozygous gsl8 insertional alleles. In addition, gsl8 mutants and inducible RNA interference lines of GSL8 showed reduced callose deposition at cell plates and/or new cell walls. Together, these data show that the GSL8 gene encodes a putative callose synthase required for cytokinesis and seedling maturation. In addition, gsl8 mutants disrupt cellular and tissue-level patterning, as shown by the presence of clusters of stomata in direct contact and by islands of excessive cell proliferation in the developing epidermis. Thus, GSL8 is required for patterning as well as cytokinesis during Arabidopsis development.
Chen
Xiong-Yan
XY
Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Plant Molecular Biology and Biotechnology Research Center, Environmental Biotechnology National Core Research Center, Jinju 660-701, Korea.
Liu
Lin
L
Lee
Eunkyoung
E
Han
Xiao
X
Rim
Yeonggil
Y
Chu
Hyosub
H
Kim
Seon-Won
SW
Sack
Fred
F
Kim
Jae-Yean
JY
D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics; D002473:Cell Wall / Q000378:metabolism / Q000648:ultrastructure; D048749:Cytokinesis / Q000235:genetics*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010641:Phenotype; D034622:RNA Interference; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000254:growth & development
D029681:Arabidopsis Proteins; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase