Abstract
A 2-year field study was undertaken to examine the effect of the systemic fungicide metalaxyl-m (the R enantiomer of metalaxyl) on endophytic populations of bacteria in tubers of potatoes (Solanum tuberosum) 'Russet Burbank'. The frequency (population density) of bacterial endophytes with antibiosis activity against Phytophthora erythroseptica and Fusarium avenaceum was not independent of fungicide regime, according to Fisher's exact test (two-tailed; P = 0.0032). Significantly more strains with antibiosis activity (in vitro) were recovered from the tubers of plants treated with metalaxyl-m. A weak, but statistically significant (P = 0.01) increase in the strength of antibiosis activity of tuber bacterial endophytes against selected phytopathogens occurred in plants that received foliar fungicide spray programmes incorporating metalaxyl-m (Ridomil Gold® MZ 68 WP (wettable powder)) in addition to chlorothalonil (Bravo® 500), as compared with plants that received Bravo 500 applications only. Disease development was significantly (P = 0.01) reduced in tubers from plants receiving metalaxyl-m treatments, following tuber inoculation with P. erythroseptica or F. avenaceum. Indices for evenness of distribution and for diversity of bacterial species recovered from potato tubers were significantly higher (P = 0.05) in plants receiving metalaxyl-m treatments. It would appear that, in stimulating a more biodiverse endophyte community, metalaxyl-m may be inducing a form of defensive mutualism amongst bacterial endophytes (a chemically induced endophyte-mediated disease suppression), thereby reducing phytopathogen colonization, including that of the fusaria, against which metalaxyl-m has no direct fungicidal activity.
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Claims 8
Claim · model-written summary
Fungicide regime was associated with density of antagonistic endophytes.
- Taxon
- potato
Solanum tuberosumt0 - Treatment
- fungicide regimee0
- Outcome
- frequency (population density) of bacterial endophytese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The frequency (population density) of bacterial endophytes with antibiosis activity against Phytophthora erythroseptica and Fusarium avenaceum was not independent of fungicide regime, according to Fisher's exact test (two-tailed; P = 0.0032).”
t0“potato”
Claim · model-written summary
Metalaxyl-m treated tubers yielded more strains with antibiosis activity.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- metalaxyl-me0
- Outcome
- strains with antibiosis activitye0
- Direction
- moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significantly more strains with antibiosis activity (in vitro) were recovered from the tubers of plants treated with metalaxyl-m.”
t0“potato”
Claim · model-written summary
Metalaxyl-m plus chlorothalonil weakly increased endophyte antibiosis versus chlorothalonil alone.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- metalaxyl-m (Ridomil Gold® MZ 68 WP (wettable powder)) in addition to chlorothalonil (Bravo® 500)e0
- Outcome
- strength of antibiosis activity of tuber bacterial endophytese0
- Direction
- increasee0
- Comparator
- Bravo 500 applications onlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A weak, but statistically significant (P = 0.01) increase in the strength of antibiosis activity of tuber bacterial endophytes against selected phytopathogens occurred in plants that received foliar fungicide spray programmes incorporating metalaxyl-m (Ridomil Gold® MZ 68 WP (wettable powder)) in addition to chlorothalonil (Bravo® 500), as compared with plants that received Bravo 500 applications only.”
t0“potato”
Claim · model-written summary
Metalaxyl-m reduced disease development after P. erythroseptica inoculation.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- metalaxyl-m treatmentse0
- Interactor
- P. erythroseptica
_with_Phytophthora_erythroseptica_zoospores_fmicb-10-00131-g003.jpg?width=60)
Phytophthora erythrosepticae0pathogen - Outcome
- Disease developmente0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_with_Phytophthora_erythroseptica_zoospores_fmicb-10-00131-g003.jpg?width=500)
Verbatim
e0“Disease development was significantly (P = 0.01) reduced in tubers from plants receiving metalaxyl-m treatments, following tuber inoculation with P. erythroseptica or F. avenaceum.”
t0“potato”
Claim · model-written summary
Metalaxyl-m reduced disease development after F. avenaceum inoculation.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- metalaxyl-m treatmentse0
- Interactor
- F. avenaceum
Fusarium avenaceume0pathogen - Outcome
- Disease developmente0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Disease development was significantly (P = 0.01) reduced in tubers from plants receiving metalaxyl-m treatments, following tuber inoculation with P. erythroseptica or F. avenaceum.”
t0“potato”
Claim · model-written summary
Metalaxyl-m increased endophyte species evenness.
- Taxon
- potatoSolanum tuberosume0
- Treatment
- metalaxyl-m treatmentse0
- Outcome
- evenness of distributione0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Indices for evenness of distribution and for diversity of bacterial species recovered from potato tubers were significantly higher (P = 0.05) in plants receiving metalaxyl-m treatments.”
Claim · model-written summary
Metalaxyl-m increased endophyte species diversity.
- Taxon
- potatoSolanum tuberosume0
- Treatment
- metalaxyl-m treatmentse0
- Outcome
- diversity of bacterial speciese0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Indices for evenness of distribution and for diversity of bacterial species recovered from potato tubers were significantly higher (P = 0.05) in plants receiving metalaxyl-m treatments.”
Claim · model-written summary
The authors propose that metalaxyl-m induced defensive mutualism through greater endophyte biodiversity.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- metalaxyl-me0
- Outcome
- defensive mutualism amongst bacterial endophytese0
- Qualifier
- more biodiverse endophyte communitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in stimulating a more biodiverse endophyte community, metalaxyl-m may be inducing a form of defensive mutualism amongst bacterial endophytes”
t0“potato”
The same questions in other papers
metalaxyl-M · Phytophthora erythroseptica · Solanum tuberosum (potato)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 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.