Format

Send to

Choose Destination
PLoS One. 2013;8(2):e55277. doi: 10.1371/journal.pone.0055277. Epub 2013 Feb 12.

Cyclic nucleotide gated channels 7 and 8 are essential for male reproductive fertility.

Author information

1
Department of Biochemistry, University of Nevada, Reno, Nevada, United States of America.

Abstract

The Arabidopsis thaliana genome contains 20 CNGCs, which are proposed to encode cyclic nucleotide gated, non-selective, Ca²⁺-permeable ion channels. CNGC7 and CNGC8 are the two most similar with 74% protein sequence identity, and both genes are preferentially expressed in pollen. Two independent loss-of-function T-DNA insertions were identified for both genes and used to generate plant lines in which only one of the two alleles was segregating (e.g., cngc7-1+/-/cngc8-2-/- and cngc7-3-/-/cngc8-1+/-). While normal pollen transmission was observed for single gene mutations, pollen harboring mutations in both cngc7 and 8 were found to be male sterile (transmission efficiency reduced by more than 3000-fold). Pollen grains harboring T-DNA disruptions of both cngc7 and 8 displayed a high frequency of bursting when germinated in vitro. The male sterile defect could be rescued through pollen expression of a CNGC7 or 8 transgene including a CNGC7 with an N-terminal GFP-tag. However, rescue efficiencies were reduced ∼10-fold when the CNGC7 or 8 included an F to W substitution (F589W and F624W, respectively) at the junction between the putative cyclic nucleotide binding-site and the calmodulin binding-site, identifying this junction as important for proper functioning of a plant CNGC. Using confocal microscopy, GFP-CNGC7 was found to preferentially localize to the plasma membrane at the flanks of the growing tip. Together these results indicate that CNGC7 and 8 are at least partially redundant and provide an essential function at the initiation of pollen tube tip growth.

PMID:
23424627
PMCID:
PMC3570425
DOI:
10.1371/journal.pone.0055277
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Public Library of Science Icon for PubMed Central
Loading ...
Support Center