Abstract
Cell cultures of Asian pear ( Pyrus pyrifolia ) are known to produce benzoate‐derived biphenyl phytoalexins upon elicitor treatment. Although the downstream pathway for biphenyl phytoalexin biosynthesis is almost known, the upstream route of benzoic acid biosynthesis in pear has not been completely elucidated. In the present work, we report benzaldehyde synthase (BS) activity from yeast extract‐treated cell suspension cultures of P. pyrifolia . BS catalyzes the in vitro conversion of trans ‐cinnamic acid to benzaldehyde using a non‐oxidative C 2 ‐side chain cleavage mechanism. The enzyme activity was strictly dependent on the presence of a reducing agent, dithiothreitol being preferred. C 2 ‐side chain shortening of the cinnamic acid backbone resembled the mechanisms catalyzed by 4‐hydroxybenzaldehyde synthase (HBS) activity in Vanilla planifolia and salicylaldehyde synthase (SAS) activity in tobacco and apple cell cultures. A basal BS activity was also observed in the non‐elicited cell cultures. Upon yeast extract‐treatment, a 13‐fold increase in BS activity was observed when compared to the non‐treated control cells. Moreover, feeding of the cell cultures with trans ‐cinnamic acid, the substrate for BS, resulted in an enhanced level of noraucuparin, a biphenyl phytoalexin. Comparable accumulation of noraucuparin was observed upon feeding of benzaldehyde, the BS product. The preferred substrate for BS was found to be trans ‐cinnamic acid, for which the apparent K m and V max values were 0.5 mM and 50.7 pkat mg −1 protein, respectively. Our observations indicate the contribution of BS to benzoic acid biosynthesis in Asian pear via the CoA‐independent and non‐ β ‐oxidative route.
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Claims 11
Claim · model-written summary
Benzaldehyde synthase activity occurred in yeast extract-treated pear cell cultures.
- Taxon
- P. pyrifolia
_Pyrus_pyrifolia_flowers.jpg?width=60)
Pyrus pyrifoliae0 - Treatment
- yeast extract‐treatede0
- Outcome
- benzaldehyde synthase (BS) activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Pyrus_pyrifolia_flowers.jpg?width=500)
Verbatim
e0“we report benzaldehyde synthase (BS) activity from yeast extract‐treated cell suspension cultures of P. pyrifolia”
Claim · model-written summary
Pear benzaldehyde synthase converted trans-cinnamic acid to benzaldehyde by non-oxidative C2 side-chain cleavage.
- Taxon
- pear
_Poirier_Fleurs_et_feuilles.jpg?width=60)
Pyrus communist0 - Gene
- BSe0
- Outcome
- conversion of trans ‐cinnamic acid to benzaldehydee0
- Qualifier
- non‐oxidative C 2 ‐side chain cleavage mechanisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Poirier_Fleurs_et_feuilles.jpg?width=500)
Verbatim
e0“BS catalyzes the in vitro conversion of trans ‐cinnamic acid to benzaldehyde using a non‐oxidative C 2 ‐side chain cleavage mechanism.”
t0“pear”
Claim · model-written summary
Benzaldehyde synthase activity depended on a reducing agent, preferably dithiothreitol.
- Taxon
- pearPyrus communist0
- Compound
- dithiothreitole0
- Outcome
- enzyme activitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The enzyme activity was strictly dependent on the presence of a reducing agent, dithiothreitol being preferred.”
t0“pear”
Claim · model-written summary
Non-elicited pear cells had basal benzaldehyde synthase activity.
- Taxon
- pearPyrus communist0
- Outcome
- basal BS activitye0
- Qualifier
- non‐elicited cell culturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A basal BS activity was also observed in the non‐elicited cell cultures.”
t0“pear”
Claim · model-written summary
Yeast extract treatment increased pear benzaldehyde synthase activity 13-fold relative to untreated cells.
- Taxon
- pearPyrus communist0
- Treatment
- yeast extract‐treatmente0
- Outcome
- BS activitye0
- Direction
- increasee0
- Value
- 13‐folde0
- Comparator
- non‐treated control cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon yeast extract‐treatment, a 13‐fold increase in BS activity was observed when compared to the non‐treated control cells.”
t0“pear”
Claim · model-written summary
Feeding trans-cinnamic acid increased noraucuparin in pear cells.
- Taxon
- pearPyrus communist0
- Treatment
- feeding of the cell cultures with trans ‐cinnamic acide0
- Outcome
- level of noraucuparine0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“feeding of the cell cultures with trans ‐cinnamic acid, the substrate for BS, resulted in an enhanced level of noraucuparin”
t0“pear”
Claim · model-written summary
Feeding benzaldehyde led to comparable noraucuparin accumulation.
- Taxon
- pearPyrus communist0
- Treatment
- feeding of benzaldehydee0
- Outcome
- accumulation of noraucuparine0
- Direction
- Comparablee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparable accumulation of noraucuparin was observed upon feeding of benzaldehyde, the BS product.”
t0“pear”
Claim · model-written summary
Trans-cinnamic acid was the preferred benzaldehyde synthase substrate.
- Taxon
- pearPyrus communist0
- Gene
- BSe0
- Compound
- trans ‐cinnamic acide0
- Outcome
- preferred substratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The preferred substrate for BS was found to be trans ‐cinnamic acid”
t0“pear”
Claim · model-written summary
For trans-cinnamic acid, apparent Km was 0.5 mM.
- Taxon
- pearPyrus communist0
- Outcome
- K me0
- Value
- 0.5 mMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the apparent K m and V max values were 0.5 mM and 50.7 pkat mg −1 protein, respectively”
t0“pear”
Claim · model-written summary
For trans-cinnamic acid, apparent Vmax was 50.7 pkat mg −1 protein.
- Taxon
- pearPyrus communist0
- Outcome
- V maxe0
- Value
- 50.7 pkat mg −1 proteine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the apparent K m and V max values were 0.5 mM and 50.7 pkat mg −1 protein, respectively”
t0“pear”
Claim · model-written summary
The authors inferred that benzaldehyde synthase contributes to pear benzoic acid biosynthesis through a CoA-independent, non-beta-oxidative route.
- Taxon
- Asian pearPyrus pyrifoliae0
- Gene
- BSe0
- Outcome
- benzoic acid biosynthesise0
- Qualifier
- CoA‐independent and non‐ β ‐oxidative routee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our observations indicate the contribution of BS to benzoic acid biosynthesis in Asian pear via the CoA‐independent and non‐ β ‐oxidative route.”
The same questions in other papers
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- negative
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- positive
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- positive
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.