Abstract
BACKGROUND: Amino acid-derived aldoximes and nitriles play important roles in plant defence. They are well-known as precursors for constitutive defence compounds such as cyanogenic glucosides and glucosinolates, but are also released as volatiles after insect feeding. Cytochrome P450 monooxygenases (CYP) of the CYP79 family catalyze the formation of aldoximes from the corresponding amino acids. However, the majority of CYP79s characterized so far are involved in cyanogenic glucoside or glucosinolate biosynthesis and only a few have been reported to be responsible for nitrogenous volatile production. RESULTS: In this study we analysed and compared the jasmonic acid-induced volatile blends of two Erythroxylum species, the cultivated South American crop species E. coca and the African wild species E. fischeri. Both species produced different nitrogenous compounds including aliphatic aldoximes and an aromatic nitrile. Four isolated CYP79 genes (two from each species) were heterologously expressed in yeast and biochemically characterized. CYP79D62 from E. coca and CYP79D61 and CYP79D60 from E. fischeri showed broad substrate specificity in vitro and converted L-phenylalanine, L-isoleucine, L-leucine, L-tryptophan, and L-tyrosine into the respective aldoximes. In contrast, recombinant CYP79D63 from E. coca exclusively accepted L-tryptophan as substrate. Quantitative real-time PCR revealed that CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves. CONCLUSIONS: The kinetic parameters of the enzymes expressed in vitro coupled with the expression patterns of the corresponding genes and the accumulation and emission of (E/Z)-phenylacetaldoxime, (E/Z)-indole-3-acetaldoxime, (E/Z)-3-methylbutyraldoxime, and (E/Z)-2-methylbutyraldoxime in jasmonic acid-treated leaves suggest that CYP79D60, CYP79D61, and CYP79D62 accept L-phenylalanine, L-leucine, L-isoleucine, and L-tryptophan as substrates in vivo and contribute to the production of volatile and semi-volatile nitrogenous defence compounds in E. coca and E. fischeri.
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Claims 9
Claim · model-written summary
E. coca produced aliphatic aldoximes and an aromatic nitrile.
- Taxon
- E. coca
Erythroxylum cocat0 - Outcome
- aliphatic aldoximes and an aromatic nitrilee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both species produced different nitrogenous compounds including aliphatic aldoximes and an aromatic nitrile.”
t0“the cultivated South American crop species E. coca”
Claim · model-written summary
E. fischeri produced aliphatic aldoximes and an aromatic nitrile.
- Taxon
- E. fischeriErythroxylum fischerit0
- Outcome
- aliphatic aldoximes and an aromatic nitrilee0
Verbatim
e0“Both species produced different nitrogenous compounds including aliphatic aldoximes and an aromatic nitrile.”
t0“the African wild species E. fischeri”
Claim · model-written summary
E. coca CYP79D62 converted five amino acid substrates to aldoximes in vitro.
- Taxon
- E. cocaErythroxylum cocae0
- Gene
- CYP79D62e0
- Outcome
- respective aldoximese0
- Qualifier
- broad substrate specificity in vitroe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CYP79D62 from E. coca and CYP79D61 and CYP79D60 from E. fischeri showed broad substrate specificity in vitro and converted L-phenylalanine, L-isoleucine, L-leucine, L-tryptophan, and L-tyrosine into the respective aldoximes.”
Claim · model-written summary
E. fischeri CYP79D61 and CYP79D60 converted five amino acid substrates to aldoximes in vitro.
- Taxon
- E. fischeriErythroxylum fischerie0
- Gene
- CYP79D61 and CYP79D60e0
- Outcome
- respective aldoximese0
- Qualifier
- broad substrate specificity in vitroe0
Verbatim
e0“CYP79D62 from E. coca and CYP79D61 and CYP79D60 from E. fischeri showed broad substrate specificity in vitro and converted L-phenylalanine, L-isoleucine, L-leucine, L-tryptophan, and L-tyrosine into the respective aldoximes.”
Claim · model-written summary
E. coca CYP79D63 accepted only L-tryptophan.
- Taxon
- E. cocaErythroxylum cocae0
- Gene
- CYP79D63e0
- Outcome
- exclusively accepted L-tryptophan as substratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“recombinant CYP79D63 from E. coca exclusively accepted L-tryptophan as substrate.”
Claim · model-written summary
CYP79D60 was significantly upregulated in jasmonic acid-treated leaves.
- Taxon
- Erythroxylum
Erythroxylume0 - Organ / stage
- leavese0
- Treatment
- jasmonic acid-treatede0
- Gene
- CYP79D60e0
- Outcome
- upregulatede0
- Direction
- upregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves.”
Claim · model-written summary
CYP79D61 was significantly upregulated in jasmonic acid-treated leaves.
- Taxon
- ErythroxylumErythroxylume0
- Organ / stage
- leavese0
- Treatment
- jasmonic acid-treatede0
- Gene
- CYP79D61e0
- Outcome
- upregulatede0
- Direction
- upregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves.”
Claim · model-written summary
CYP79D62 was significantly upregulated in jasmonic acid-treated leaves.
- Taxon
- ErythroxylumErythroxylume0
- Organ / stage
- leavese0
- Treatment
- jasmonic acid-treatede0
- Gene
- CYP79D62e0
- Outcome
- upregulatede0
- Direction
- upregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CYP79D60, CYP79D61, and CYP79D62 were significantly upregulated in jasmonic acid-treated Erythroxylum leaves.”
Claim · model-written summary
Authors infer three CYP79D enzymes contribute to nitrogenous defence compounds in both Erythroxylum species.
- Taxon
- E. coca and E. fischeriErythroxylum cocaErythroxylum fischerie0
- Gene
- CYP79D60, CYP79D61, and CYP79D62e0
- Outcome
- volatile and semi-volatile nitrogenous defence compoundse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CYP79D60, CYP79D61, and CYP79D62 accept L-phenylalanine, L-leucine, L-isoleucine, and L-tryptophan as substrates in vivo and contribute to the production of volatile and semi-volatile nitrogenous defence compounds in E. coca and E. fischeri.”