Auxin biosynthesis in the phytopathogenic fungus Leptosphaeria maculans is associated with enhanced transcription of indole-3-pyruvate decarboxylase LmIPDC2 and tryptophan aminotransferase LmTAM1
Language English Country France Media print-electronic
Document type Journal Article
PubMed
32540203
DOI
10.1016/j.resmic.2020.05.001
PII: S0923-2508(20)30054-1
Knihovny.cz E-resources
- Keywords
- Dothideomycetes, Hormone, Indole-3-pyruvate decarboxylase, Tryptamine, Tryptophan, Tryptophan aminotransferase,
- MeSH
- Aminohydrolases genetics MeSH
- Biosynthetic Pathways MeSH
- Brassica napus microbiology MeSH
- Phylogeny MeSH
- Transcription, Genetic MeSH
- Fungi classification genetics metabolism MeSH
- Carboxy-Lyases genetics metabolism MeSH
- Indoleacetic Acids metabolism pharmacology MeSH
- Leptosphaeria enzymology genetics growth & development metabolism MeSH
- Gene Expression Regulation, Fungal MeSH
- Plant Growth Regulators metabolism MeSH
- Tryptamines metabolism pharmacology MeSH
- Tryptophan metabolism pharmacology MeSH
- Tryptophan Transaminase genetics metabolism MeSH
- Up-Regulation MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Aminohydrolases MeSH
- indoleacetic acid MeSH Browser
- indolepyruvate decarboxylase MeSH Browser
- Carboxy-Lyases MeSH
- Indoleacetic Acids MeSH
- nitrilase MeSH Browser
- Plant Growth Regulators MeSH
- tryptamine MeSH Browser
- Tryptamines MeSH
- Tryptophan MeSH
- Tryptophan Transaminase MeSH
Auxins are hormones that regulate growth and development in plants. Besides plants, various microorganisms also produce auxins. Here we investigate whether and how the phytopathogenic fungus Leptosphaeria maculans biosynthesizes auxins. We characterized the auxin profile of in vitro grown L. maculans. The culture was further supplied with the auxin biosynthetic-precursors tryptophan and tryptamine and gene expression and phytohormone content was analyzed. L. maculans in vitro produced IAA (indole-3-acetic acid) as the predominant auxin metabolite. IAA production could be further stimulated by supplying precursors. Expression of indole-3-pyruvate decarboxylase LmIPDC2, tryptophan aminotransferase LmTAM1 and nitrilase LmNIT1 genes was mainly upregulated after adding tryptophan and correlated with IAA production, suggesting that these genes are the key components of auxin biosynthesis in L. maculans. Tryptamine acted as a potent inducer of IAA production, though a pathway independent of LmIPDC2/LmTAM1 may be involved. Despite L. maculans being a rich source of bioactive IAA, the auxin metabolic profile of host plant Brassica napus was not altered upon infection. Exogenous IAA inhibited the growth of L. maculans in vitro when supplied in high concentration. Altogether, we showed that L. maculans is capable of IAA production and we have identified biosynthetic genes that were responsive to tryptophan treatment.
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