Abstract
Phenolic secondary metabolites are often thought to protect plants against attack by microbes, but their role in defense against pathogen infection in woody plants has not been investigated comprehensively. We studied the biosynthesis, occurrence, and antifungal activity of flavan-3-ols in black poplar (Populus nigra), which include both monomers, such as catechin, and oligomers, known as proanthocyanidins (PAs). We identified and biochemically characterized three leucoanthocyanidin reductases and two anthocyanidin reductases from P. nigra involved in catalyzing the last steps of flavan-3-ol biosynthesis, leading to the formation of catechin [2,3-trans-(+)-flavan-3-ol] and epicatechin [2,3-cis-(−)-flavan-3-ol], respectively. Poplar trees that were inoculated with the biotrophic rust fungus (Melampsora larici-populina) accumulated higher amounts of catechin and PAs than uninfected trees. The de novo-synthesized catechin and PAs in the rust-infected poplar leaves accumulated significantly at the site of fungal infection in the lower epidermis. In planta concentrations of these compounds strongly inhibited rust spore germination and reduced hyphal growth. Poplar genotypes with constitutively higher levels of catechin and PAs as well as hybrid aspen (Populus tremula × Populus alba) overexpressing the MYB134 transcription factor were more resistant to rust infection. Silencing PnMYB134, on the other hand, decreased flavan-3-ol biosynthesis and increased susceptibility to rust infection. Taken together, our data indicate that catechin and PAs are effective antifungal defenses in poplar against foliar rust infection.
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Claims 10
Claim · model-written summary
Three leucoanthocyanidin reductases and two anthocyanidin reductases of Populus nigra catalyzing the last steps of flavan-3-ol biosynthesis were identified and biochemically characterized.
- Taxon
- P. nigra
Populus nigrae0 - Gene
- three leucoanthocyanidin reductases and two anthocyanidin reductasese0
- Outcome
- last steps of flavan-3-ol biosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified and biochemically characterized three leucoanthocyanidin reductases and two anthocyanidin reductases from P. nigra involved in catalyzing the last steps of flavan-3-ol biosynthesis”
Claim · model-written summary
Poplar trees inoculated with the rust fungus Melampsora larici-populina accumulated higher amounts of catechin and proanthocyanidins than uninfected trees.
- Treatment
- inoculated with the biotrophic rust funguse0
- Interactor
- Melampsora larici-populinae0pathogen
- Outcome
- amounts of catechin and PAse0
- Direction
- highere0
- Comparator
- uninfected treese0
PopulusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Poplar trees that were inoculated with the biotrophic rust fungus (Melampsora larici-populina) accumulated higher amounts of catechin and PAs than uninfected trees”
Claim · model-written summary
De novo-synthesized catechin and PAs in rust-infected poplar leaves accumulated significantly at the site of fungal infection in the lower epidermis.
- Organ / stage
- lower epidermise0
- Outcome
- de novo-synthesized catechin and PAse0
- Qualifier
- site of fungal infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The de novo-synthesized catechin and PAs in the rust-infected poplar leaves accumulated significantly at the site of fungal infection in the lower epidermis”
Claim · model-written summary
In planta concentrations of catechin and PAs strongly inhibited rust spore germination.
- Taxon
- Populus nigraPopulus nigrae1
- Treatment
- In planta concentrations of these compoundse0
- Interactor
- ruste0pathogen
- Outcome
- rust spore germinatione0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In planta concentrations of these compounds strongly inhibited rust spore germination”
e1“black poplar (Populus nigra)”
Claim · model-written summary
In planta concentrations of catechin and PAs reduced rust hyphal growth.
- Taxon
- Populus nigraPopulus nigrae1
- Treatment
- In planta concentrations of these compoundse0
- Interactor
- ruste0pathogen
- Outcome
- hyphal growthe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In planta concentrations of these compounds strongly inhibited rust spore germination and reduced hyphal growth”
e1“black poplar (Populus nigra)”
Claim · model-written summary
Poplar genotypes with constitutively higher levels of catechin and PAs were more resistant to rust infection.
- Interactor
- ruste1pathogen
- Compound
- catechin and PAse0
- Outcome
- resistant to rust infectione1
- Direction
- more resistante1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Poplar genotypes with constitutively higher levels of catechin and PAs”
e1“were more resistant to rust infection”
Claim · model-written summary
Hybrid aspen overexpressing the MYB134 transcription factor was more resistant to rust infection.
- Taxon
- hybrid aspene0
- Treatment
- overexpressing the MYB134 transcription factore0
- Interactor
- ruste1pathogen
- Outcome
- resistant to rust infectione1
- Direction
- more resistante1
Not reportedComparator
Verbatim
e0“hybrid aspen (Populus tremula × Populus alba) overexpressing the MYB134 transcription factor”
e1“were more resistant to rust infection”
Claim · model-written summary
Silencing PnMYB134 decreased flavan-3-ol biosynthesis.
- Taxon
- Populus nigraPopulus nigrae1
- Treatment
- Silencing PnMYB134e0
- Gene
- PnMYB134e0
- Outcome
- flavan-3-ol biosynthesise0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Silencing PnMYB134, on the other hand, decreased flavan-3-ol biosynthesis”
e1“black poplar (Populus nigra)”
Claim · model-written summary
Silencing PnMYB134 increased susceptibility to rust infection.
- Taxon
- Populus nigraPopulus nigrae1
- Treatment
- Silencing PnMYB134e0
- Interactor
- ruste0pathogen
- Gene
- PnMYB134e0
- Outcome
- susceptibility to rust infectione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Silencing PnMYB134, on the other hand, decreased flavan-3-ol biosynthesis and increased susceptibility to rust infection”
e1“black poplar (Populus nigra)”
Claim · model-written summary
Catechin and PAs are effective antifungal defenses in poplar against foliar rust infection.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“catechin and PAs are effective antifungal defenses in poplar against foliar rust infection”
The same questions in other papers
inoculation · molecular: metabolites · Populus (poplar)Positive and negative results
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See all 7 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.