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Regulation of the cutinases expressed by Aspergillus nidulans and evaluation of their role in cutin degradation
Four cutinase genes are encoded in the genome of the saprophytic fungus Aspergillus nidulans , but only two of them have proven to codify for active cutinases. However, their overall roles in cutin degradation are unknown, and there is scarce information on the regulatory effectors of their expressi...
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Published in: | Applied microbiology and biotechnology 2019-05, Vol.103 (9), p.3863-3874 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Four cutinase genes are encoded in the genome of the saprophytic fungus
Aspergillus nidulans
, but only two of them have proven to codify for active cutinases. However, their overall roles in cutin degradation are unknown, and there is scarce information on the regulatory effectors of their expression. In this work, the expression of the cutinase genes was assayed by multiplex qRT-PCR in cultures grown in media containing both inducer and repressor carbon sources. The genes
ancut1
and
ancut2
were induced by cutin and its monomers, while
ancut3
was constitutively expressed. Besides, cutin induced
ancut4
only under oxidative stress conditions. An in silico analysis of the upstream regulatory sequences suggested binding regions for the lipid metabolism transcription factors (TF) FarA for
ancut1
and
ancut2
while FarB for
ancut3
. For
ancut4
, the analysis suggested binding to NapA (the stress response TF). These binding possibilities were experimentally tested by transcriptional analysis using the
A
.
nidulans
mutants ANΔ
farA
, ANΔ
farB
, and ANΔnapA. Regarding cutin degradation, spectroscopic and chromatographic methods showed similar products from ANCUT1 and ANCUT3. In addition, ANCUT1 produced 9,10-dihydroxy hexadecanoic acid, suggesting an endo-cleavage action of this enzyme. Regarding ANCUT2 and ANCUT4, they produced omega fatty acids. Our results confirmed the cutinolytic activity of the four cutinases, allowed identification of their specific roles in the cutinolytic system and highlighted their differences in the regulatory mechanisms and affinity towards natural substrates. This information is expected to impact the cutinase production processes and broaden their current biotechnological applications. |
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ISSN: | 0175-7598 1432-0614 |
DOI: | 10.1007/s00253-019-09712-3 |