Auxin biosynthesis in the phytopathogenic fungus Leptosphaeria maculans is associated with enhanced transcription of indole-3-pyruvate decarboxylase LmIPDC2 and tryptophan aminotransferase LmTAM1

0531931 - ÚEB 2021 RIV NL eng J - Journal Article
Leontovyčová, Hana - Trdá, Lucie - Dobrev, Petre - Šašek, Vladimír - Gay, E. - Balesdent, M.H. - Burketová, Lenka
Auxin biosynthesis in the phytopathogenic fungus Leptosphaeria maculans is associated with enhanced transcription of indole-3-pyruvate decarboxylase LmIPDC2 and tryptophan aminotransferase LmTAM1.
Research in Microbiology. Roč. 171, 5-6 (2020), s. 174-184. ISSN 0923-2508. E-ISSN 1769-7123
R&D Projects: GA ČR GA13-26798S; GA MŠMT(CZ) EF16_019/0000738
Institutional support: RVO:61389030
Keywords : Dothideomycetes * Hormone * Indole-3-pyruvate decarboxylase * Tryptamine * Tryptophan * Tryptophan aminotransferase
OECD category: Biochemical research methods
Impact factor: 3.992, year: 2020
Method of publishing: Open access
http://doi.org/10.1016/j.resmic.2020.05.001

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.
Permanent Link: http://hdl.handle.net/11104/0310564