Abstract
Nonvolatile terpenoid phytoalexins occur throughout the plant kingdom, but until recently were not known constituents of chemical defense in maize (Zea mays). We describe a novel family of ubiquitous maize sesquiterpenoid phytoalexins, termed zealexins, which were discovered through characterization of Fusarium graminearum-induced responses. Zealexins accumulate to levels greater than 800 μg g⁻¹ fresh weight in F. graminearum-infected tissue. Their production is also elicited by a wide variety of fungi, Ostrinia nubilalis herbivory, and the synergistic action of jasmonic acid and ethylene. Zealexins exhibit antifungal activity against numerous phytopathogenic fungi at physiologically relevant concentrations. Structural elucidation of four members of this complex family revealed that all are acidic sesquiterpenoids containing a hydrocarbon skeleton that resembles β-macrocarpene. Induced zealexin accumulation is preceded by increased expression of the genes encoding TERPENE SYNTHASE6 (TPS6) and TPS11, which catalyze β-macrocarpene production. Furthermore, zealexin accumulation displays direct positive relationships with the transcript levels of both genes. Microarray analysis of F. graminearum-infected tissue revealed that Tps6/Tps11 were among the most highly up-regulated genes, as was An2, an ent-copalyl diphosphate synthase associated with production of kauralexins. Transcript profiling suggests that zealexins cooccur with a number of antimicrobial proteins, including chitinases and pathogenesis-related proteins. In addition to zealexins, kauralexins and the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one-glucose (HDMBOA-glucose) were produced in fungal-infected tissue. HDMBOA-glucose accumulation occurred in both wild-type and benzoxazine-deficient1 (bx1) mutant lines, indicating that Bx1 gene activity is not required for HDMBOA biosynthesis. Together these results indicate an important cooperative role of terpenoid phytoalexins in maize biochemical defense.
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Claims 16
Claim · model-written summary
A novel family of ubiquitous maize sesquiterpenoid phytoalexins, termed zealexins, was described.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We describe a novel family of ubiquitous maize sesquiterpenoid phytoalexins, termed zealexins”
Claim · model-written summary
Zealexins accumulated to more than 800 ug per g fresh weight in F. graminearum-infected tissue.
- Interactor
- F. graminearum
_on_Corn_(Zea_mays)_at_Waimea%2C_Hawaii.jpg?width=60)
Fusarium graminearume0pathogen - Outcome
- Zealexins accumulatee0
- Value
- greater than 800 μg g⁻¹ fresh weighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_on_Corn_(Zea_mays)_at_Waimea%2C_Hawaii.jpg?width=500)
Verbatim
t0“Maize”
e0“Zealexins accumulate to levels greater than 800 μg g⁻¹ fresh weight in F. graminearum-infected tissue”
Claim · model-written summary
Zealexin production is elicited by a wide variety of fungi.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Their production is also elicited by a wide variety of fungi, Ostrinia nubilalis herbivory, and the synergistic action of jasmonic acid and ethylene”
Claim · model-written summary
Zealexin production is elicited by Ostrinia nubilalis herbivory.
- Treatment
- Ostrinia nubilalis herbivorye0
- Interactor
- Ostrinia nubilalis
Ostrinia nubilalise0herbivore - Outcome
- Their productione0
- Direction
- elicitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Their production is also elicited by a wide variety of fungi, Ostrinia nubilalis herbivory, and the synergistic action of jasmonic acid and ethylene”
Claim · model-written summary
Zealexin production is elicited by the synergistic action of jasmonic acid and ethylene.
- Treatment
- synergistic action of jasmonic acid and ethylenee0
- Outcome
- Their productione0
- Direction
- elicitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Their production is also elicited by a wide variety of fungi, Ostrinia nubilalis herbivory, and the synergistic action of jasmonic acid and ethylene”
Claim · model-written summary
Zealexins showed antifungal activity against numerous phytopathogenic fungi at physiologically relevant concentrations.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Zealexins exhibit antifungal activity against numerous phytopathogenic fungi at physiologically relevant concentrations”
Claim · model-written summary
Four zealexins were all acidic sesquiterpenoids with a hydrocarbon skeleton resembling beta-macrocarpene.
- Outcome
- acidic sesquiterpenoids containing a hydrocarbon skeleton that resembles β-macrocarpenee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Structural elucidation of four members of this complex family revealed that all are acidic sesquiterpenoids containing a hydrocarbon skeleton that resembles β-macrocarpene”
Claim · model-written summary
Induced zealexin accumulation is preceded by increased expression of the genes encoding TPS6 and TPS11.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Induced zealexin accumulation is preceded by increased expression of the genes encoding TERPENE SYNTHASE6 (TPS6) and TPS11”
Claim · model-written summary
Zealexin accumulation shows direct positive relationships with transcript levels of both TPS genes.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“zealexin accumulation displays direct positive relationships with the transcript levels of both genes”
Claim · model-written summary
Tps6 and Tps11 were among the most highly up-regulated genes in F. graminearum-infected tissue.
- Interactor
- F. graminearumFusarium graminearume0pathogen
- Gene
- Tps6/Tps11e0
- Outcome
- most highly up-regulated genese0
- Direction
- up-regulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Microarray analysis of F. graminearum-infected tissue revealed that Tps6/Tps11 were among the most highly up-regulated genes, as was An2, an ent-copalyl diphosphate synthase associated with production of kauralexins”
Claim · model-written summary
An2, an ent-copalyl diphosphate synthase, was among the most highly up-regulated genes in F. graminearum-infected tissue.
- Interactor
- F. graminearumFusarium graminearume0pathogen
- Gene
- An2e0
- Outcome
- most highly up-regulated genese0
- Direction
- up-regulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Microarray analysis of F. graminearum-infected tissue revealed that Tps6/Tps11 were among the most highly up-regulated genes, as was An2, an ent-copalyl diphosphate synthase associated with production of kauralexins”
Claim · model-written summary
Zealexins co-occur with a number of antimicrobial proteins including chitinases and pathogenesis-related proteins.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“Transcript profiling suggests that zealexins cooccur with a number of antimicrobial proteins, including chitinases and pathogenesis-related proteins”
Claim · model-written summary
Kauralexins and the benzoxazinoid HDMBOA-glucose were produced in fungal-infected tissue.
- Outcome
- kauralexins and the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one-glucose (HDMBOA-glucose)e0
- Qualifier
- fungal-infected tissuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“kauralexins and the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one-glucose (HDMBOA-glucose) were produced in fungal-infected tissue”
Claim · model-written summary
HDMBOA-glucose accumulation occurred in both wild-type and bx1 mutant lines.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“HDMBOA-glucose accumulation occurred in both wild-type and benzoxazine-deficient1 (bx1) mutant lines”
Claim · model-written summary
Bx1 gene activity is not required for HDMBOA biosynthesis.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Maize”
e0“indicating that Bx1 gene activity is not required for HDMBOA biosynthesis”
Claim · model-written summary
Terpenoid phytoalexins have an important cooperative role in maize biochemical defense.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an important cooperative role of terpenoid phytoalexins in maize biochemical defense”
The same questions in other papers
ethene · yield · Zea mays (maize)Positive and negative results
1 in the opposite direction
- negative
Ostrinia nubilalis · yield · Zea mays (maize)Positive and negative results
2 in the opposite direction
- negative
- no effect
jasmonic acid · yield · Zea mays (maize)Results agree
1 paper in the same direction as this paper
- positive
grazing · yield · Zea mays (maize)Results differ
10 papers in the same direction as this paper · 22 in the opposite direction · 3 reporting no difference from an alternative
- no effect
- no effect
- no effect
32 papers more in this group
See all 36 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.