Callose synthase (CalS5) is required for exine formation during microgametogenesis and for pollen viability in Arabidopsis

Callose (beta-1,3-glucan) is produced at different locations in response to biotic and abiotic cues. Arabidopsis contains 12 genes encoding callose synthase (CalS). We demonstrate that one of these genes, CalS5, encodes a callose synthase which is responsible for the synthesis of callose deposited a...

Full description

Saved in:
Bibliographic Details
Published in:The Plant journal : for cell and molecular biology 2005-05, Vol.42 (3), p.315-328
Main Authors: Dong, X, Hong, Z, Sivaramakrishnan, M, Mahfouz, M, Verma, D.P.S
Format: Article
Language:English
Subjects:
1,3-beta-glucan synthase
Arabidopsis
Arabidopsis - cytology
Arabidopsis - enzymology
Arabidopsis Proteins - metabolism
Arabidopsis thaliana
beta-1,3-glucan synthase
Biological and medical sciences
Botany
callose
cell walls
Enzymes
exine wall
Flowers & plants
Fundamental and applied biological sciences. Psychology
gametogenesis
gametophytes
Gene Expression Regulation, Plant
Genes
Glucosyltransferases - metabolism
hexosyltransferases
knockout mutants
male sterility
Males
megasporogenesis
meiosis
Meiosis - physiology
microspores
microsporogenesis
molecular sequence data
nucleotide sequences
plant fertility
plant physiology
Plant physiology and development
plant proteins
Pollen
Pollen - metabolism
Pollen - ultrastructure
pollen development
Sexual reproduction
transmembrane proteins
Vegetative and sexual reproduction, floral biology, fructification
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Callose (beta-1,3-glucan) is produced at different locations in response to biotic and abiotic cues. Arabidopsis contains 12 genes encoding callose synthase (CalS). We demonstrate that one of these genes, CalS5, encodes a callose synthase which is responsible for the synthesis of callose deposited at the primary cell wall of meiocytes, tetrads and microspores, and the expression of this gene is essential for exine formation in pollen wall. CalS5 encodes a transmembrane protein of 1923 amino acid residues with a molecular mass of 220 kDa. Knockout mutations of the CalS5 gene by T-DNA insertion resulted in a severe reduction in fertility. The reduced fertility in the cals5 mutants is attributed to the degeneration of microspores. However, megagametogenesis is not affected and the female gametes are completely fertile in cals5 mutants. The CalS5 gene is also expressed in other organs with the highest expression in meiocytes, tetrads, microspores and mature pollen. Callose deposition in the cals5 mutant was nearly completely lacking, suggesting that this gene is essential for the synthesis of callose in these tissues. As a result, the pollen exine wall was not formed properly, affecting the baculae and tectum structure and tryphine was deposited randomly as globular structures. These data suggest that callose synthesis has a vital function in building a properly sculpted exine, the integrity of which is essential for pollen viability.
ISSN:0960-7412
1365-313X
DOI:10.1111/j.1365-313x.2005.02379.x