Abstract
While the mechanisms underlying quantitative resistance of plants to pathogens are still not fully elucidated, the Pathogen-Associated Molecular Patterns (PAMPs)-triggered response model suggests that such resistance depends on a dynamic interplay between the plant and the pathogen. In this model, the pathogens themselves or elicitors they produce would induce general defense pathways, which in turn limit pathogen growth and host colonisation. It therefore suggests that quantitative resistance is directly linked to a common set of general host defense mechanisms, but experimental evidence is still inconclusive. We tested the PAMP-triggered model using two pathogens (Pectobacterium atrosepticum and Phytophthora infestans) differing by their infectious processes and five potato cultivars spanning a range of resistance levels to each pathogen. Phenylalanine ammonia-lyase (PAL) activity, used as a defense marker, and accumulation of phenolics were measured in tuber slices challenged with lipopolysaccharides from P. atrosepticum or a concentrated culture filtrate from P. infestans. PAL activity increased following treatment with the filtrate but not with lipopolysaccharides, and varied among cultivars. It was positively related to tuber resistance to P. atrosepticum, but negatively related to tuber resistance to P. infestans. It was also positively related to the accumulation of total phenolics. Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro, showing that PAL induction caused active defense against each of them. Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum, but not to P. infestans. Our results show that inducing a general defense mechanism does not necessarily result in quantitative resistance. As such, they invalidate the hypothesis that the PAMP-triggered model alone can explain quantitative resistance. We thus designed a more complex model integrating physiological host response and a key pathogen life history trait, pathogen growth, to explain the differences between the two pathosystems.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 13
Claim · model-written summary
Culture filtrate increased PAL activity.
- Taxon
- potato
Solanum tuberosume1 - Treatment
- the filtratee0
- Interactor
- P. infestans
Phytophthora infestanse2pathogen - Outcome
- PAL activitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PAL activity increased following treatment with the filtrate but not with lipopolysaccharides”
e1“five potato cultivars”
e2“a concentrated culture filtrate from P. infestans”
Claim · model-written summary
Lipopolysaccharides did not increase PAL activity.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- lipopolysaccharidese0
- Interactor
- P. atrosepticum
Pectobacterium atrosepticume2pathogen - Outcome
- PAL activitye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PAL activity increased following treatment with the filtrate but not with lipopolysaccharides”
e1“five potato cultivars”
e2“lipopolysaccharides from P. atrosepticum”
Claim · model-written summary
PAL activity varied among potato cultivars.
- Taxon
- potatoSolanum tuberosume1
- Outcome
- PAL activitye0
- Direction
- variede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PAL activity increased following treatment with the filtrate but not with lipopolysaccharides, and varied among cultivars”
e1“five potato cultivars”
Claim · model-written summary
PAL activity was positively related to resistance to P. atrosepticum.
- Taxon
- potatoSolanum tuberosume1
- Interactor
- P. atrosepticumPectobacterium atrosepticume0pathogen
- Outcome
- tuber resistance to P. atrosepticume0
- Direction
- positivelye0
- Comparator
- PAL activitye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It was positively related to tuber resistance to P. atrosepticum”
e1“five potato cultivars”
e2“PAL activity increased”
Claim · model-written summary
PAL activity was negatively related to resistance to P. infestans.
- Taxon
- potatoSolanum tuberosume1
- Interactor
- P. infestansPhytophthora infestanse0pathogen
- Outcome
- tuber resistance to P. infestanse0
- Direction
- negativelye0
- Comparator
- PAL activitye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“negatively related to tuber resistance to P. infestans”
e1“five potato cultivars”
e2“PAL activity increased”
Claim · model-written summary
PAL activity was positively related to total phenolic accumulation.
- Taxon
- potatoSolanum tuberosume1
- Outcome
- accumulation of total phenolicse0
- Direction
- positivelye0
- Comparator
- PAL activitye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It was also positively related to the accumulation of total phenolics”
e1“five potato cultivars”
e2“PAL activity increased”
Claim · model-written summary
Chlorogenic acid was the main accumulated phenolic.
- Taxon
- potatoSolanum tuberosume1
- Outcome
- Chlorogenic acid, the main phenolic accumulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorogenic acid, the main phenolic accumulated”
e1“five potato cultivars”
Claim · model-written summary
Chlorogenic acid inhibited P. atrosepticum growth in vitro.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- Chlorogenic acide0
- Interactor
- Pectobacterium atrosepticumPectobacterium atrosepticume2pathogen
- Outcome
- growth of both pathogense0
- Direction
- inhibitede0
- Setting
- in vitroe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro”
e1“five potato cultivars”
e2“Pectobacterium atrosepticum and Phytophthora infestans”
Claim · model-written summary
Chlorogenic acid inhibited P. infestans growth in vitro.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- Chlorogenic acide0
- Interactor
- Phytophthora infestansPhytophthora infestanse2pathogen
- Outcome
- growth of both pathogense0
- Direction
- inhibitede0
- Setting
- in vitroe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro”
e1“five potato cultivars”
e2“Pectobacterium atrosepticum and Phytophthora infestans”
Claim · model-written summary
Prior PAL induction increased resistance to P. atrosepticum.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- PAL activity had been induced before inoculatione0
- Interactor
- P. atrosepticumPectobacterium atrosepticume0pathogen
- Outcome
- resistance to P. atrosepticume0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum”
e1“five potato cultivars”
Claim · model-written summary
Prior PAL induction did not increase resistance to P. infestans.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- PAL activity had been induced before inoculatione0
- Interactor
- P. infestansPhytophthora infestanse0pathogen
- Outcome
- P. infestanse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum, but not to P. infestans”
e1“five potato cultivars”
Claim · model-written summary
The authors conclude that general defense induction does not necessarily produce quantitative resistance.
- Taxon
- potatoSolanum tuberosume1
- Outcome
- quantitative resistancee0
- Qualifier
- inducing a general defense mechanisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inducing a general defense mechanism does not necessarily result in quantitative resistance”
e1“five potato cultivars”
Claim · model-written summary
A model integrating host response and pathogen growth was designed to explain the pathosystems.
- Taxon
- potatoSolanum tuberosume1
- Outcome
- differences between the two pathosystemse0
- Comparator
- pathogen growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a more complex model integrating physiological host response and a key pathogen life history trait, pathogen growth, to explain the differences between the two pathosystems”
e1“five potato cultivars”
The same questions in other papers
chlorogenic acid · Phytophthora infestans · Solanum tuberosum (potato)Positive and negative results
1 reporting no difference from an alternative
- no effect
lipopolysaccharide · Pectobacterium atrosepticum · Solanum tuberosum (potato)Positive and negative results
1 in the opposite direction
- positive
inoculation · Pectobacterium atrosepticum · Solanum tuberosum (potato)Positive and negative results
2 papers in the same direction as this paper · 5 in the opposite direction
- negative
- negative
- negative
4 papers more in this group
See all 8 papers →inoculation · Phytophthora infestans · Solanum tuberosum (potato)Positive and negative results
15 papers in the same direction as this paper · 24 in the opposite direction
- positive
- positive
- positive
36 papers more in this group
See all 40 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.