The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i>
In <i>Aspergillus nidulans</i> L-rhamnose is catabolised to pyruvate and L-lactaldehyde, and the latter ultimately to L-lactate, via the non-phosphorylated pathway (LRA) encoded by the genes <i>lraA</i>-<i>D</i>, and <i>aldA</i> that encodes a broad su...
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MDPI AG
2022-11-01
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| Series: | Journal of Fungi |
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| Online Access: | https://www.mdpi.com/2309-608X/8/11/1181 |
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| author | Margarita Orejas Andrew P. MacCabe |
| author_facet | Margarita Orejas Andrew P. MacCabe |
| author_sort | Margarita Orejas |
| collection | DOAJ |
| description | In <i>Aspergillus nidulans</i> L-rhamnose is catabolised to pyruvate and L-lactaldehyde, and the latter ultimately to L-lactate, via the non-phosphorylated pathway (LRA) encoded by the genes <i>lraA</i>-<i>D</i>, and <i>aldA</i> that encodes a broad substrate range aldehyde dehydrogenase (ALDH) that also functions in ethanol utilisation. LRA pathway expression requires both the pathway-specific transcriptional activator RhaR (<i>rhaR</i> is expressed constitutively) and the presence of L-rhamnose. The deletion of <i>lraA</i> severely impairs growth when L-rhamnose is the sole source of carbon and in addition it abolishes the induction of genes that respond to L-rhamnose/RhaR, indicating that an intermediate of the LRA pathway is the physiological inducer likely required to activate RhaR. The loss-of-function mutation <i>aldA67</i> also has a severe negative impact on growth on L-rhamnose but, in contrast to the deletion of <i>lraA</i>, the expression levels of L-rhamnose/RhaR-responsive genes under inducing conditions are substantially up-regulated and the production of α-L-rhamnosidase activity is greatly increased compared to the <i>aldA</i><sup>+</sup> control. These findings are consistent with accumulation of the physiological inducer as a consequence of the loss of ALDH activity. Our observations suggest that <i>aldA</i> loss-of-function mutants could be biotechnologically relevant candidates for the over-production of α-L-rhamnosidase activity or the expression of heterologous genes driven by RhaR-responsive promoters. |
| first_indexed | 2024-03-09T18:56:57Z |
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| language | English |
| last_indexed | 2024-03-09T18:56:57Z |
| publishDate | 2022-11-01 |
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| series | Journal of Fungi |
| spelling | doaj.art-b731d009962c4a52b3cd620bbbdc35f62023-11-24T05:24:31ZengMDPI AGJournal of Fungi2309-608X2022-11-01811118110.3390/jof8111181The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i>Margarita Orejas0Andrew P. MacCabe1Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), c/Catedrático Agustín Escardino Benlloch 7, 46980 Paterna, Valencia, SpainInstituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), c/Catedrático Agustín Escardino Benlloch 7, 46980 Paterna, Valencia, SpainIn <i>Aspergillus nidulans</i> L-rhamnose is catabolised to pyruvate and L-lactaldehyde, and the latter ultimately to L-lactate, via the non-phosphorylated pathway (LRA) encoded by the genes <i>lraA</i>-<i>D</i>, and <i>aldA</i> that encodes a broad substrate range aldehyde dehydrogenase (ALDH) that also functions in ethanol utilisation. LRA pathway expression requires both the pathway-specific transcriptional activator RhaR (<i>rhaR</i> is expressed constitutively) and the presence of L-rhamnose. The deletion of <i>lraA</i> severely impairs growth when L-rhamnose is the sole source of carbon and in addition it abolishes the induction of genes that respond to L-rhamnose/RhaR, indicating that an intermediate of the LRA pathway is the physiological inducer likely required to activate RhaR. The loss-of-function mutation <i>aldA67</i> also has a severe negative impact on growth on L-rhamnose but, in contrast to the deletion of <i>lraA</i>, the expression levels of L-rhamnose/RhaR-responsive genes under inducing conditions are substantially up-regulated and the production of α-L-rhamnosidase activity is greatly increased compared to the <i>aldA</i><sup>+</sup> control. These findings are consistent with accumulation of the physiological inducer as a consequence of the loss of ALDH activity. Our observations suggest that <i>aldA</i> loss-of-function mutants could be biotechnologically relevant candidates for the over-production of α-L-rhamnosidase activity or the expression of heterologous genes driven by RhaR-responsive promoters.https://www.mdpi.com/2309-608X/8/11/1181enzyme productionfilamentous fungialdehyde dehydrogenase mutant <i>aldA67</i>L-rhamnose catabolismLRA pathway engineeringplant cell wall degrading enzymes (PCWDEs) |
| spellingShingle | Margarita Orejas Andrew P. MacCabe The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> Journal of Fungi enzyme production filamentous fungi aldehyde dehydrogenase mutant <i>aldA67</i> L-rhamnose catabolism LRA pathway engineering plant cell wall degrading enzymes (PCWDEs) |
| title | The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> |
| title_full | The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> |
| title_fullStr | The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> |
| title_full_unstemmed | The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> |
| title_short | The Loss-of-Function Mutation <i>aldA67</i> Leads to Enhanced α-L-Rhamnosidase Production by <i>Aspergillus nidulans</i> |
| title_sort | loss of function mutation i alda67 i leads to enhanced α l rhamnosidase production by i aspergillus nidulans i |
| topic | enzyme production filamentous fungi aldehyde dehydrogenase mutant <i>aldA67</i> L-rhamnose catabolism LRA pathway engineering plant cell wall degrading enzymes (PCWDEs) |
| url | https://www.mdpi.com/2309-608X/8/11/1181 |
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