Abstract
The exocyst, a complex of eight proteins, contributes to the morphogenesis of polarized cells in a broad range of eukaryotes. In these organisms, the exocyst appears to facilitate vesicle docking at the plasma membrane during exocytosis. Although we had identified orthologs for each of the eight exocyst components in Arabidopsis (Arabidopsis thaliana), no function has been demonstrated for any of them in plants. The gene encoding one exocyst component ortholog, AtSEC8, is expressed in pollen and vegetative tissues of Arabidopsis. Genetic studies utilizing an allelic series of six independent T-DNA mutations reveal a role for SEC8 in male gametophyte function. Three T-DNA insertions in SEC8 cause an absolute, male-specific transmission defect that can be complemented by expression of SEC8 from the LAT52 pollen promoter. Microscopic analysis shows no obvious abnormalities in the microgametogenesis of the SEC8 mutants, and the mutant pollen grains appear to respond to the signals that initiate germination. However, in vivo assays indicate that these mutant pollen grains are unable to germinate a pollen tube. The other three T-DNA insertions are associated with a partial transmission defect, such that the mutant allele is transmitted through the pollen at a reduced frequency. The partial transmission defect is only evident when mutant gametophytes must compete with wild-type gametophytes, and arises in part from a reduced pollen tube growth rate. These data support the hypothesis that one function of the putative plant exocyst is to facilitate the initiation and maintenance of the polarized growth of pollen tubes.
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Claims 11
Claim · model-written summary
AtSEC8 is expressed in pollen and vegetative tissues of Arabidopsis.
- Taxon
- Arabidopsis
Arabidopsist0 - Organ / stage
- pollen and vegetative tissuese1
- Gene
- AtSEC8e1
- Outcome
- expressede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e1“The gene encoding one exocyst component ortholog, AtSEC8, is expressed in pollen and vegetative tissues of Arabidopsis”
Claim · model-written summary
Six independent T-DNA mutations reveal a role for SEC8 in male gametophyte function in Arabidopsis.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- six independent T-DNA mutationse2
- Gene
- SEC8e2
- Outcome
- male gametophyte functione2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e2“Genetic studies utilizing an allelic series of six independent T-DNA mutations reveal a role for SEC8 in male gametophyte function”
Claim · model-written summary
Three T-DNA insertions in SEC8 cause an absolute, male-specific transmission defect.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- Three T-DNA insertions in SEC8e3
- Gene
- SEC8e3
- Outcome
- male-specific transmission defecte3
- Qualifier
- absolutee3
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e3“Three T-DNA insertions in SEC8 cause an absolute, male-specific transmission defect”
Claim · model-written summary
The SEC8 transmission defect is complemented by expressing SEC8 from the LAT52 pollen promoter.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- expression of SEC8 from the LAT52 pollen promotere4
- Gene
- SEC8e4
- Outcome
- transmission defecte4
- Direction
- complementede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e4“male-specific transmission defect that can be complemented by expression of SEC8 from the LAT52 pollen promoter”
Claim · model-written summary
SEC8 mutants show no obvious abnormalities in microgametogenesis.
- Taxon
- ArabidopsisArabidopsist0
- Material
- SEC8 mutantse5
- Organ / stage
- microgametogenesise5
- Outcome
- abnormalities in the microgametogenesise5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e5“Microscopic analysis shows no obvious abnormalities in the microgametogenesis of the SEC8 mutants”
Claim · model-written summary
Mutant pollen grains appear to respond to the signals that initiate germination.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mutant pollen grainse6
- Organ / stage
- pollen grainse6
- Outcome
- respond to the signals that initiate germinatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e6“the mutant pollen grains appear to respond to the signals that initiate germination”
Claim · model-written summary
Mutant pollen grains are unable to germinate a pollen tube in vivo.
- Taxon
- ArabidopsisArabidopsist0
- Material
- mutant pollen grainse7
- Organ / stage
- pollen grainse7
- Outcome
- unable to germinate a pollen tubee7
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e7“in vivo assays indicate that these mutant pollen grains are unable to germinate a pollen tube”
Claim · model-written summary
The other three T-DNA insertions reduce transmission of the mutant allele through the pollen.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- other three T-DNA insertionse1
- Outcome
- transmitted through the pollene1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e1“The other three T-DNA insertions are associated with a partial transmission defect, such that the mutant allele is transmitted through the pollen at a reduced frequency”
Claim · model-written summary
The partial transmission defect is evident only when mutant gametophytes compete with wild-type gametophytes.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutant gametophytes must compete with wild-type gametophytese1
- Outcome
- partial transmission defecte1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e1“The partial transmission defect is only evident when mutant gametophytes must compete with wild-type gametophytes”
Claim · model-written summary
The partial transmission defect arises in part from reduced pollen tube growth rate.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- partial transmission defecte1
- Qualifier
- arises in part from a reduced pollen tube growth ratee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e1“The partial transmission defect is only evident when mutant gametophytes must compete with wild-type gametophytes”
e2“arises in part from a reduced pollen tube growth rate”
Claim · model-written summary
The putative plant exocyst may facilitate the initiation and maintenance of polarised pollen tube growth.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- polarized growth of pollen tubese1
- Qualifier
- facilitate the initiation and maintenance of the polarized growth of pollen tubese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Putative Arabidopsis Exocyst Complex”
e1“one function of the putative plant exocyst is to facilitate the initiation and maintenance of the polarized growth of pollen tubes”
The same questions in other papers
transgenic · disease · ArabidopsisPositive and negative results
35 papers in the same direction as this paper · 19 in the opposite direction
- no effect
- negative
- negative
51 papers more in this group
See all 55 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.