Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum
Abstract Background The transition to a more environmentally friendly economy has prompted studies of modern biorefineries, including the utilization of low-value lignocellulose. The major challenge facing the widespread application of biorefineries is the high cost of enzymes that can efficiently h...
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2017-11-01
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Series: | Biotechnology for Biofuels |
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Online Access: | http://link.springer.com/article/10.1186/s13068-017-0966-y |
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Article |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Yu-Si Yan Shuai Zhao Lu-Sheng Liao Qi-Peng He Ya-Ru Xiong Long Wang Cheng-Xi Li Jia-Xun Feng |
spellingShingle |
Yu-Si Yan Shuai Zhao Lu-Sheng Liao Qi-Peng He Ya-Ru Xiong Long Wang Cheng-Xi Li Jia-Xun Feng Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum Biotechnology for Biofuels Penicillium oxalicum Transcriptomic profiling Transcription factor Cellulase Xylanase Regulation |
author_facet |
Yu-Si Yan Shuai Zhao Lu-Sheng Liao Qi-Peng He Ya-Ru Xiong Long Wang Cheng-Xi Li Jia-Xun Feng |
author_sort |
Yu-Si Yan |
title |
Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum |
title_short |
Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum |
title_full |
Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum |
title_fullStr |
Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum |
title_full_unstemmed |
Transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicum |
title_sort |
transcriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in penicillium oxalicum |
publisher |
BMC |
series |
Biotechnology for Biofuels |
issn |
1754-6834 |
publishDate |
2017-11-01 |
description |
Abstract Background The transition to a more environmentally friendly economy has prompted studies of modern biorefineries, including the utilization of low-value lignocellulose. The major challenge facing the widespread application of biorefineries is the high cost of enzymes that can efficiently hydrolyze recalcitrant cellulose to sugars. Penicillium oxalicum produces large amounts of plant-cell-wall-degrading enzymes, but their production is tightly controlled by complex regulatory networks, resulting in low yields of the native enzymes. Regulatory genes have been the targets of genetic engineering to improve enzyme production in microorganisms. In this study, we used transcriptomic profiling and genetic analyses to screen for and identify novel key regulators of cellulase and xylanase gene expression in P. oxalicum. Results A comparative analysis of the transcriptomes of P. oxalicum HP7-1 on different carbon sources, including glucose, wheat bran, and wheat bran plus Avicel, identified 40 candidate genes regulating the expression of cellulolytic enzyme genes. Deletion mutants of 31 candidate genes were constructed in P. oxalicum ∆PoxKu70 and 11 resultant mutants showed significant changes in their filter-paper cellulase production compared with the parental strain ∆PoxKu70. Among these 11 mutants, ΔPoxCxrA, ΔPoxCxrB, and ΔPoxNsdD showed the most significant reduction in the enzyme production (96.8, 75.9, and 58.5%, respectively). Ten of these 11 genes are here reported to be involved in cellulase production for the first time. Further tests revealed that ΔPoxCxrA, ΔPoxCxrB, and ΔPoxNsdD displayed significantly reduced xylanase production, whereas ΔPoxCxrA produced negligible xylanase. Interestingly, ΔPoxCxrB and ΔPoxNsdD showed significantly increased β-glucosidase production. Real-time quantitative reverse transcription–PCR and an electrophoretic mobility shift assay (EMSA) showed that PoxCxrA, PoxCxrB, and PoxNsdD regulate the expression of one another, but the mode of regulation changes dynamically during the growth of fungal cells in the presence of cellulose. EMSA showed that PoxCxrA, PoxCxrB, and PoxNsdD directly bind the putative promoters of major cellulase and xylanase genes. Conclusions We have detected and identified three key new regulatory genes, PoxCxrA, PoxCxrB, and PoxNsdD, that directly and indirectly regulate the expression of cellulase and xylanase genes in P. oxalicum. This study provides novel insights into the regulatory mechanisms of fungal cellulase and xylanase gene expression. |
topic |
Penicillium oxalicum Transcriptomic profiling Transcription factor Cellulase Xylanase Regulation |
url |
http://link.springer.com/article/10.1186/s13068-017-0966-y |
work_keys_str_mv |
AT yusiyan transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT shuaizhao transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT lushengliao transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT qipenghe transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT yaruxiong transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT longwang transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT chengxili transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum AT jiaxunfeng transcriptomicprofilingandgeneticanalysesrevealnovelkeyregulatorsofcellulaseandxylanasegeneexpressioninpenicilliumoxalicum |
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doaj-02398b0548f340aab9a9820755958f4c2020-11-25T00:40:01ZengBMCBiotechnology for Biofuels1754-68342017-11-0110112010.1186/s13068-017-0966-yTranscriptomic profiling and genetic analyses reveal novel key regulators of cellulase and xylanase gene expression in Penicillium oxalicumYu-Si Yan0Shuai Zhao1Lu-Sheng Liao2Qi-Peng He3Ya-Ru Xiong4Long Wang5Cheng-Xi Li6Jia-Xun Feng7State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityState Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi UniversityAbstract Background The transition to a more environmentally friendly economy has prompted studies of modern biorefineries, including the utilization of low-value lignocellulose. The major challenge facing the widespread application of biorefineries is the high cost of enzymes that can efficiently hydrolyze recalcitrant cellulose to sugars. Penicillium oxalicum produces large amounts of plant-cell-wall-degrading enzymes, but their production is tightly controlled by complex regulatory networks, resulting in low yields of the native enzymes. Regulatory genes have been the targets of genetic engineering to improve enzyme production in microorganisms. In this study, we used transcriptomic profiling and genetic analyses to screen for and identify novel key regulators of cellulase and xylanase gene expression in P. oxalicum. Results A comparative analysis of the transcriptomes of P. oxalicum HP7-1 on different carbon sources, including glucose, wheat bran, and wheat bran plus Avicel, identified 40 candidate genes regulating the expression of cellulolytic enzyme genes. Deletion mutants of 31 candidate genes were constructed in P. oxalicum ∆PoxKu70 and 11 resultant mutants showed significant changes in their filter-paper cellulase production compared with the parental strain ∆PoxKu70. Among these 11 mutants, ΔPoxCxrA, ΔPoxCxrB, and ΔPoxNsdD showed the most significant reduction in the enzyme production (96.8, 75.9, and 58.5%, respectively). Ten of these 11 genes are here reported to be involved in cellulase production for the first time. Further tests revealed that ΔPoxCxrA, ΔPoxCxrB, and ΔPoxNsdD displayed significantly reduced xylanase production, whereas ΔPoxCxrA produced negligible xylanase. Interestingly, ΔPoxCxrB and ΔPoxNsdD showed significantly increased β-glucosidase production. Real-time quantitative reverse transcription–PCR and an electrophoretic mobility shift assay (EMSA) showed that PoxCxrA, PoxCxrB, and PoxNsdD regulate the expression of one another, but the mode of regulation changes dynamically during the growth of fungal cells in the presence of cellulose. EMSA showed that PoxCxrA, PoxCxrB, and PoxNsdD directly bind the putative promoters of major cellulase and xylanase genes. Conclusions We have detected and identified three key new regulatory genes, PoxCxrA, PoxCxrB, and PoxNsdD, that directly and indirectly regulate the expression of cellulase and xylanase genes in P. oxalicum. This study provides novel insights into the regulatory mechanisms of fungal cellulase and xylanase gene expression.http://link.springer.com/article/10.1186/s13068-017-0966-yPenicillium oxalicumTranscriptomic profilingTranscription factorCellulaseXylanaseRegulation |