Pollen tubes (PTs) grow by the targeted secretion of new cell wall material to their expanding tip region. Sec1/Munc18 (SM) proteins promote membrane fusion through regulation of the SNARE complex. We have previously shown that disruption of protein glycosylation in the
- Award ID(s):
- 1758434
- NSF-PAR ID:
- 10394996
- Editor(s):
- Freitag, Michael
- Date Published:
- Journal Name:
- PLOS Genetics
- Volume:
- 18
- Issue:
- 12
- ISSN:
- 1553-7404
- Page Range / eLocation ID:
- e1010510
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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SUMMARY Arabidopsis thaliana hpat1 hpat3 double mutant leads to PT growth defects that can be suppressed by reducing secretion. Here, we identified five point mutant alleles of the SM proteinSEC1A ashpat1/3 suppressors. The suppressors increased seed set, reduced PT growth defects and reduced the rate of glycoprotein secretion. In the absence of thehpat mutations,sec1a reduced pollen germination and PT elongation producing shorter and wider PTs. Consistent with a defect in membrane fusion,sec1a PTs accumulated secretory vesicles. Thoughsec1a had significantly reduced male transmission, homozygoussec1a plants maintained full seed set, demonstrating thatSEC1A was ultimately dispensable for pollen fertility. However, when combined with a mutation in anotherSEC1 ‐likeSM gene,keule , pollen fertility was totally abolished. Mutation insec1b , the final member of the Arabidopsis SEC1 clade, did not enhance thesec1a phenotype. Thus, SEC1A is the major SM protein promoting pollen germination and tube elongation, but in its absence KEULE can partially supply this activity. When we examined the expression of the SM protein family in other species for which pollen expression data were available, we found that at least one Sec1‐like protein was highly expressed in pollen samples, suggesting a conserved role in pollen fertility in other species. -
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1371/journal.pgen.1010510
