Abstract
Summary Flavonols form an important class of flavonoids which serve an essential function during plant reproduction. Flavonoid biosynthesis is initiated by the enzyme chalcone synthase (CHS). A high abundance of flavonols and chs mRNA was demonstrated in male and female reproductive organs of Petunia hybrida . Detailed analyses revealed precise spatial and temporal regulation of the chs promoter and flavonol synthesis in the stigma, style and ovules. Transgenic plants were generated with a complete block of flavonol biosynthesis as the result of anti‐sense inhibition of chs gene activity. The absence of flavonols by this dominant mutation rendered these plants self‐sterile. Pollination experiments with wild‐type and mutant plants revealed that the production of flavonols in either the anthers or the pistils was required for pollen tube growth and seed set. Mutant pollen without flavonols in their exine germinated normally. However, after a short period of in vitro pollen tube growth the tips of these tubes disrupted and the protoplasm was disloaded leading to the death of the pollen grain. Addition of flavonol aglycones but not other flavonoids complemented this phenotype. Confocal laser scanning microscopy revealed the localization of high levels of flavonols throughout the wild‐type pollen tube. These compounds were not detected in the exine or cell wall of growing tubes. In addition, it was observed that the flavone apigenin could completely inhibit pollen tube growth. Taken together, it is shown that flavonols play an important role in the growth of the pollen tube and their mode of action is discussed.
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Claims 13
Claim · model-written summary
Flavonols and chs mRNA were abundant in male and female reproductive organs.
- Taxon
- Petunia hybrida
Petunia ×hybridae0 - Organ / stage
- male and female reproductive organse0
- Gene
- chse0
- Outcome
- flavonols and chs mRNAe0
- Direction
- high abundancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A high abundance of flavonols and chs mRNA was demonstrated in male and female reproductive organs of Petunia hybrida”
Claim · model-written summary
The chs promoter and flavonol synthesis were spatially and temporally regulated in stigma, style and ovules.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Organ / stage
- stigma, style and ovulese0
- Gene
- chse0
- Outcome
- spatial and temporal regulation of the chs promoter and flavonol synthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Detailed analyses revealed precise spatial and temporal regulation of the chs promoter and flavonol synthesis in the stigma, style and ovules.”
t0“Petunia hybrida”
Claim · model-written summary
Antisense inhibition of chs blocked flavonol biosynthesis.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Treatment
- anti‐sense inhibition of chs gene activitye0
- Gene
- chse0
- Outcome
- flavonol biosynthesise0
- Direction
- complete blocke0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic plants were generated with a complete block of flavonol biosynthesis as the result of anti‐sense inhibition of chs gene activity.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonol absence rendered mutant plants self sterile.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Treatment
- absence of flavonolse0
- Outcome
- self‐sterilee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The absence of flavonols by this dominant mutation rendered these plants self‐sterile.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonol production in either anthers or pistils was required for pollen tube growth.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Organ / stage
- anthers or the pistilse0
- Outcome
- pollen tube growthe0
- Qualifier
- production of flavonolse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the production of flavonols in either the anthers or the pistils was required for pollen tube growth and seed set.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonol production in either anthers or pistils was required for seed set.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Organ / stage
- anthers or the pistilse0
- Outcome
- seed sete0
- Qualifier
- production of flavonolse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the production of flavonols in either the anthers or the pistils was required for pollen tube growth and seed set.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonol deficient mutant pollen germinated normally.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Material
- Mutant pollene0
- Organ / stage
- exinee0
- Outcome
- germinated normallye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mutant pollen without flavonols in their exine germinated normally.”
t0“Petunia hybrida”
Claim · model-written summary
Mutant pollen tubes ruptured after a short period in vitro and pollen grains died.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Organ / stage
- pollen tubee0
- Outcome
- tips of these tubes disrupted and the protoplasm was disloadede0
- Setting
- in vitroe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after a short period of in vitro pollen tube growth the tips of these tubes disrupted and the protoplasm was disloaded leading to the death of the pollen grain.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonol aglycones rescued the mutant pollen tube phenotype.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Treatment
- flavonol aglyconese0
- Outcome
- complemented this phenotypee0
- Comparator
- other flavonoidse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of flavonol aglycones but not other flavonoids complemented this phenotype.”
t0“Petunia hybrida”
Claim · model-written summary
Other flavonoids did not rescue the mutant pollen tube phenotype.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Treatment
- other flavonoidse0
- Outcome
- complemented this phenotypee0
- Comparator
- flavonol aglyconese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of flavonol aglycones but not other flavonoids complemented this phenotype.”
t0“Petunia hybrida”
Claim · model-written summary
Wild type pollen tubes contained high flavonol levels throughout.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Material
- wild‐typee0
- Organ / stage
- pollen tubee0
- Outcome
- levels of flavonolse0
- Direction
- highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high levels of flavonols throughout the wild‐type pollen tube.”
t0“Petunia hybrida”
Claim · model-written summary
Flavonols were not detected in growing tube exine or cell wall.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Organ / stage
- exine or cell wall of growing tubese0
- Outcome
- not detectede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These compounds were not detected in the exine or cell wall of growing tubes.”
t0“Petunia hybrida”
Claim · model-written summary
Apigenin completely inhibited pollen tube growth.
- Taxon
- Petunia hybridaPetunia ×hybridat0
- Treatment
- apigenine0
- Outcome
- pollen tube growthe0
- Direction
- inhibite0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the flavone apigenin could completely inhibit pollen tube growth.”
t0“Petunia hybrida”