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Li W, Li P, Deng Y, Situ J, He Z, Zhou W, Li M, Xi P, Liang X, Kong G, Jiang Z. A plant cell death-inducing protein from litchi interacts with Peronophythora litchii pectate lyase and enhances plant resistance. Nat Commun 2024; 15:22. [PMID: 38167822 PMCID: PMC10761943 DOI: 10.1038/s41467-023-44356-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
Cell wall degrading enzymes, including pectate lyases (PeLs), released by plant pathogens, break down protective barriers and/or activate host immunity. The direct interactions between PeLs and plant immune-related proteins remain unclear. We identify two PeLs, PlPeL1 and PlPeL1-like, critical for full virulence of Peronophythora litchii on litchi (Litchi chinensis). These proteins enhance plant susceptibility to oomycete pathogens in a PeL enzymatic activity-dependent manner. However, LcPIP1, a plant immune regulator secreted by litchi, binds to PlPeL1/PlPeL1-like, and attenuates PlPeL1/PlPeL1-like induced plant susceptibility to Phytophthora capsici. LcPIP1 also induces cell death and various immune responses in Nicotiana benthamiana. Conserved in plants, LcPIP1 homologs bear a conserved "VDMASG" motif and exhibit immunity-inducing activity. Furthermore, SERK3 interacts with LcPIP1 and is required for LcPIP1-induced cell death. NbPIP1 participates in immune responses triggered by the PAMP protein INF1. In summary, our study reveals the dual roles of PlPeL1/PlPeL1-like in plant-pathogen interactions: enhancing pathogen virulence through PeL enzymatic activity while also being targeted by LcPIP1, thus enhancing plant immunity.
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Affiliation(s)
- Wen Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Peng Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yizhen Deng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Junjian Situ
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Zhuoyuan He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Wenzhe Zhou
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Minhui Li
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Pinggen Xi
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Xiangxiu Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Guanghui Kong
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.
| | - Zide Jiang
- National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China.
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Zou M, Guo F, Li X, Zhao J, Qu Y. Enhancing production of alkaline polygalacturonate lyase from Bacillus subtilis by fed-batch fermentation. PLoS One 2014; 9:e90392. [PMID: 24603713 PMCID: PMC3946182 DOI: 10.1371/journal.pone.0090392] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/29/2014] [Indexed: 11/19/2022] Open
Abstract
Alkaline polygalacturonate lyase (PGL, EC 4.2.2.2) is an enzyme used in many industries. We developed a fed-batch fermentation process that combines the enzymatic pretreatment of the carbon source with controlling the pH of the fermentative broth to enhance the PGL production from Bacillus subtilis 7-3-3 to decrease the production cost. Maintaining the fermentation broth at pH 6.5 prior to feeding with ammonia and at pH 6.0 after feeding significantly improved PGL activity (743.5 U mL-1) compared with the control (202.5 U mL-1). The average PGL productivity reached 19.6 U mL-1 h-1 after 38 h of fermentation. The crude PGL was suitable for environmentally friendly ramie enzymatic degumming.
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Affiliation(s)
- Mouyong Zou
- State Key Laboratory of Microbial Technology, Shandong University, Ji-nan City, P.R. China
| | - Fenfen Guo
- State Key Laboratory of Microbial Technology, Shandong University, Ji-nan City, P.R. China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Ji-nan City, P.R. China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Ji-nan City, P.R. China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, Ji-nan City, P.R. China
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3
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Tamayo-Ramos JA, Flipphi M, Pardo E, Manzanares P, Orejas M. L-rhamnose induction of Aspergillus nidulans α-L-rhamnosidase genes is glucose repressed via a CreA-independent mechanism acting at the level of inducer uptake. Microb Cell Fact 2012; 11:26. [PMID: 22353731 PMCID: PMC3312857 DOI: 10.1186/1475-2859-11-26] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/21/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Little is known about the structure and regulation of fungal α-L-rhamnosidase genes despite increasing interest in the biotechnological potential of the enzymes that they encode. Whilst the paradigmatic filamentous fungus Aspergillus nidulans growing on L-rhamnose produces an α-L-rhamnosidase suitable for oenological applications, at least eight genes encoding putative α-L-rhamnosidases have been found in its genome. In the current work we have identified the gene (rhaE) encoding the former activity, and characterization of its expression has revealed a novel regulatory mechanism. A shared pattern of expression has also been observed for a second α-L-rhamnosidase gene, (AN10277/rhaA). RESULTS Amino acid sequence data for the oenological α-L-rhamnosidase were determined using MALDI-TOF mass spectrometry and correspond to the amino acid sequence deduced from AN7151 (rhaE). The cDNA of rhaE was expressed in Saccharomyces cerevisiae and yielded pNP-rhamnohydrolase activity. Phylogenetic analysis has revealed this eukaryotic α-L-rhamnosidase to be the first such enzyme found to be more closely related to bacterial rhamnosidases than other α-L-rhamnosidases of fungal origin. Northern analyses of diverse A. nidulans strains cultivated under different growth conditions indicate that rhaA and rhaE are induced by L-rhamnose and repressed by D-glucose as well as other carbon sources, some of which are considered to be non-repressive growth substrates. Interestingly, the transcriptional repression is independent of the wide domain carbon catabolite repressor CreA. Gene induction and glucose repression of these rha genes correlate with the uptake, or lack of it, of the inducing carbon source L-rhamnose, suggesting a prominent role for inducer exclusion in repression. CONCLUSIONS The A. nidulans rhaE gene encodes an α-L-rhamnosidase phylogenetically distant to those described in filamentous fungi, and its expression is regulated by a novel CreA-independent mechanism. The identification of rhaE and the characterization of its regulation will facilitate the design of strategies to overproduce the encoded enzyme - or homologs from other fungi - for industrial applications. Moreover, A. nidulans α-L-rhamnosidase encoding genes could serve as prototypes for fungal genes coding for plant cell wall degrading enzymes regulated by a novel mechanism of CCR.
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Affiliation(s)
- Juan A Tamayo-Ramos
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Agustín Escardino 7, 46980 Paterna, Valencia, Spain
- Present address: Fungal Systems Biology, Laboratory of Systems and Synthetic Biology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands
| | - Michel Flipphi
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Ester Pardo
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Paloma Manzanares
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Margarita Orejas
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Agustín Escardino 7, 46980 Paterna, Valencia, Spain
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Zhao Q, Ding R, Kang Y, Chen J. Expression of pectate lyase A from Aspergillus nidulans in Bacillus subtilis. World J Microbiol Biotechnol 2008. [DOI: 10.1007/s11274-008-9784-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Miyara I, Shafran H, Kramer Haimovich H, Rollins J, Sherman A, Prusky D. Multi-factor regulation of pectate lyase secretion by Colletotrichum gloeosporioides pathogenic on avocado fruits. MOLECULAR PLANT PATHOLOGY 2008; 9:281-91. [PMID: 18705870 PMCID: PMC6640356 DOI: 10.1111/j.1364-3703.2007.00462.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Tissue alkalinization during Colletotrichum gloeosporioides attack enhances the expression of PELB, which encodes pectate lyase (PL), and PL secretion, which is considered essential for full virulence. We studied the regulation of PL secretion by manipulation of C. gloeosporioides PELB. PELB was down-regulated by knocking out PAC1, which encodes the PacC transcription factor that regulates gene products with pH-sensitive activities. We functionally characterized a PACC gene homologue, PAC1, from C. gloeosporioides wild-type (WT) Cg-14 and two independent deletion strains, Deltapac1(372)and Deltapac1(761). Loss-of-function PAC1 mutants showed 85% reduction of PELB transcript expression, delayed PL secretion and dramatically reduced virulence, as detected in infection assays with avocado fruits. In contrast, PELB was up-regulated in the presence of carbon sources such as glucose. When glucose was used as a carbon source in the medium for the WT strain and the Deltapac1 mutant at pH 6.0, PELB transcript expression and PL secretion were activated. Other sugars, such as sucrose and fructose (but not galactose), also activated PELB expression. These results suggest that the pH-regulated response is only part of a multi-factor regulation of PELB, and that sugars are also needed to promote the transition from quiescent to active necrotrophic development by the pathogen.
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Affiliation(s)
- I Miyara
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
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6
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Zhao Q, Yuan S, Zhang Y, Zhu H, Dai C, Yang F, Han F. Expression, purification and characterization of pectate lyase A from Aspergillus nidulans in Escherichia coli. World J Microbiol Biotechnol 2006. [DOI: 10.1007/s11274-006-9331-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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7
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Kramer-Haimovich H, Servi E, Katan T, Rollins J, Okon Y, Prusky D. Effect of ammonia production by Colletotrichum gloeosporioides on pelB activation, pectate lyase secretion, and fruit pathogenicity. Appl Environ Microbiol 2006; 72:1034-9. [PMID: 16461646 PMCID: PMC1392887 DOI: 10.1128/aem.72.2.1034-1039.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The accumulation of ammonia and associated tissue alkalinization predispose avocado fruit to attack by Colletotrichum gloeosporioides. Secretion of ammonia by C. gloeosporioides in the presence of KNO3 was induced by decreasing the pH from 7.0 to 4.0. When the fungus was grown at pH 4.0 or 6.0 in the absence of a nitrogen source, ammonia did not accumulate, and neither pelB (encoding pectate lyase) transcription nor pectate lyase secretion was detected. Under these nitrogen starvation conditions, only transcriptional activation of areA, which encodes the global nitrogen regulator, was detected. pelB transcription and pectate lyase secretion were both detected when C. gloeosporioides was grown at pH 6.0 in the presence of ammonia accumulated from different nitrogen sources. The early accumulation of ammonia induced early pelB expression and pectate lyase secretion. As the external pH increased from 4.0 to 6.0, transcripts of pac1, the C. gloeosporioides pacC homolog, also could be detected. Nit mutants of C. gloeosporioides, which cannot utilize KNO3 as a nitrogen source, did not secrete ammonia, alkalinize the medium, or secrete pectate lyase. If Nit mutants were grown at pH 6.0 in the presence of glutamate, then pectate lyase secretion was induced. Infiltration of 0.1 M ammonium hydroxide at pH 10 into ripening avocado fruits enhanced the activation of quiescent infection and symptom development by C. gloeosporioides. These results suggest that ambient pH alkalinization resulting from ammonia accumulation and the availability of ammonia as a nitrogen source independently regulate pelB expression, pectate lyase secretion, and virulence of C. gloeosporioides. These data suggest that alkalinization during C. gloeosporioides infection is important for its transformation from the quiescent biotrophic stage to the necrotrophic stage of fungal colonization in the fruit host.
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Affiliation(s)
- H Kramer-Haimovich
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
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8
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Drori N, Kramer-Haimovich H, Rollins J, Dinoor A, Okon Y, Pines O, Prusky D. External pH and nitrogen source affect secretion of pectate lyase by Colletotrichum gloeosporioides. Appl Environ Microbiol 2003; 69:3258-62. [PMID: 12788724 PMCID: PMC161482 DOI: 10.1128/aem.69.6.3258-3262.2003] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Accumulation of ammonia and associated tissue alkalinization predispose fruit to attack by Colletotrichum gloeosporioides: As the external pH increases from 4.0 to 6.0, pectate lyase (PL) and other extracellular proteins are secreted and accumulate. At pH 4.0 neither pelB (encoding PL) transcription nor PL secretion were detected; however, they were detected as the pH increased. Nitrogen assimilation also was required for PL secretion at pH 6.0. Both inorganic and organic nitrogen sources enhanced PL secretion at pH 6.0, but neither was sufficient for PL secretion at pH 4.0. Sequence analysis of the 5' upstream region of the pelB promoter revealed nine putative consensus binding sites for the Aspergillus transcription factor PacC. Consistent with this result, the transcript levels of pac1 (the C. gloeosporioides pacC homologue) and pelB increased in parallel as a function of pH. Our results suggest that the ambient pH and the nitrogen source are independent regulatory factors for processes linked to PL secretion and virulence of C. gloeosporioides.
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Affiliation(s)
- N Drori
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
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9
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de Vries RP, Visser J. Aspergillus enzymes involved in degradation of plant cell wall polysaccharides. Microbiol Mol Biol Rev 2001; 65:497-522, table of contents. [PMID: 11729262 PMCID: PMC99039 DOI: 10.1128/mmbr.65.4.497-522.2001] [Citation(s) in RCA: 542] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Degradation of plant cell wall polysaccharides is of major importance in the food and feed, beverage, textile, and paper and pulp industries, as well as in several other industrial production processes. Enzymatic degradation of these polymers has received attention for many years and is becoming a more and more attractive alternative to chemical and mechanical processes. Over the past 15 years, much progress has been made in elucidating the structural characteristics of these polysaccharides and in characterizing the enzymes involved in their degradation and the genes of biotechnologically relevant microorganisms encoding these enzymes. The members of the fungal genus Aspergillus are commonly used for the production of polysaccharide-degrading enzymes. This genus produces a wide spectrum of cell wall-degrading enzymes, allowing not only complete degradation of the polysaccharides but also tailored modifications by using specific enzymes purified from these fungi. This review summarizes our current knowledge of the cell wall polysaccharide-degrading enzymes from aspergilli and the genes by which they are encoded.
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Affiliation(s)
- R P de Vries
- Molecular Genetics of Industrial Microorganisms, Wageningen University, 6703 HA Wageningen, The Netherlands.
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Aspergillus nidulans as a model organism for the study of the expression of genes encoding enzymes of relevance in the food industry. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1874-5334(01)80011-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Molecular transformation, gene cloning, and gene expression systems for filamentous fungi. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1874-5334(01)80010-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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12
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Yakoby N, Kobiler I, Dinoor A, Prusky D. pH regulation of pectate lyase secretion modulates the attack of Colletotrichum gloeosporioides on avocado fruits. Appl Environ Microbiol 2000; 66:1026-30. [PMID: 10698767 PMCID: PMC91938 DOI: 10.1128/aem.66.3.1026-1030.2000] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Growth of Colletotrichum gloeosporioides in pectolytic enzyme-inducing medium (PEIM) increased the pH of the medium from 3. 8 to 6.5. Pectate lyase (PL) secretion was detected when the pH reached 5.8, and the level of secretion increased up to pH 6.5. PL gene (pel) transcript production began at pH 5.0 and increased up to pH 5.7. PL secretion was never detected when the pH of the inducing medium was lower than 5.8 or when C. gloeosporioides hyphae were transferred from PL-secreting conditions at pH 6.5 to pH 3.8. This behavior differed from that of polygalacturonase (PG), where pg transcripts and protein secretion were detected at pH 5.0 and continued up to 5.7. Under in vivo conditions, the pH of unripe pericarp of freshly harvested avocado (Persea americana cv. Fuerte) fruits, resistant to C. gloeosporioides attack, was 5.2, whereas in ripe fruits, when decay symptoms were expressed, the pericarp pH had increased to 6.3. Two avocado cultivars, Ardit and Ettinger, which are resistant to C. gloeosporioides attack, had pericarp pHs of less than 5.5, which did not increase during ripening. The present results suggest that host pH regulates the secretion of PL and may affect C. gloeosporioides pathogenicity. The mechanism found in avocado may have equivalents in other post-harvest pathosystems and suggests new approaches for breeding against and controlling post-harvest diseases.
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Affiliation(s)
- N Yakoby
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel
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13
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Abstract
Many microorganisms prefer easily metabolizable carbon sources over alternative, less readily metabolized carbon sources. One of the mechanisms to achieve this is repression of the synthesis of enzymes related to catabolism of the alternative carbon sources, i.e. carbon repression. It is now clear that in Aspergillus nidulans and Aspergillus niger the repressor protein CREA plays a major role in carbon repression. CREA inhibits transcription of many target genes by binding to specific sequences in the promoter of these genes. Unfortunately there is little information on other components of the signalling pathway that triggers repression by CREA. In this review we summarize the current understanding of carbon repression in Aspergilli.
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Affiliation(s)
- G J Ruijter
- Section Molecular Genetics of Industrial Microorganisms, Wageningen Agricultural University, The Netherlands
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14
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Petersen TN, Kauppinen S, Larsen S. The crystal structure of rhamnogalacturonase A from Aspergillus aculeatus: a right-handed parallel beta helix. Structure 1997; 5:533-44. [PMID: 9115442 DOI: 10.1016/s0969-2126(97)00209-8] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Pectic substances are the major polysaccharide components of the middle lamella and primary cell wall of dicotyledonous plants. They consist of homogalacturonan 'smooth' regions and highly rhamnified 'hairy' regions of rhamnogalacturonan. The backbone in rhamnogalacturonan-l (RG-l), which is composed of alternating galacturonic acid and rhamnose residues, is the substrate for a new class of enzymes known as rhamnogalacturnoases (RGases). RGase A is a novel enzyme implicated in the enzymatic degradation of RG-l. RESULTS The structure of RGase A from Aspergillus aculeatus has been solved by the single isomorphous replacement method including anomalous scattering (SIRAS method) to 2.0 A resolution. The enzyme folds into a large right-handed parallel beta helix, with a core composed of 13 turns of beta strands. Four parallel beta sheets (PB1, PB1a, PB2 and PB3), formed by the consecutive turns, are typically separated by a residue in the conformation of a left-handed alpha helix. As a consequence of the consecutive turns, 32% of all residues have their sidechains aligned at the surface or in the interior of the parallel beta helix. The aligned residues at the surface are dominated by threonine, aspartic acid and asparagine, whereas valine, leucine and isoleucine are most frequently found in the interior. A very large hydrophobic cavity is found in the interior of the parallel beta helix. The potential active site is a groove, oriented almost perpendicular to the helical axis, containing a cluster of three aspartic acid residues and one glutamic acid residue. The enzyme is highly glycosylated; two N-linked and eighteen O-linked glycosylation sites have been found in the structure. CONCLUSIONS Rhamnogalacturonase A from A. aculeatus is the first three-dimensional structure of an enzyme hydrolyzing glycoside bonds within the backbone of RG-l. The large groove, which is the potential active site of RGase A, is also seen in the structures of pectate lyases. Two catalytic aspartic acid residues, which have been proposed to have a catalytic role, reside in this area of RGase A. The distance between the aspartic acid residues is consistent with the inverting mechanism of catalysis. The glycan groups bound to RGase A are important to the stability of the crystal, as the carbohydrate moiety is involved in most of the intermolecular hydrogen bonds.
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Affiliation(s)
- T N Petersen
- Centre for Crystallographic Studies, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark
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15
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Expression of anErwinia pectate lyase in three species ofAspergillus. Curr Genet 1996. [DOI: 10.1007/bf02221517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Guo W, González-Candelas L, Kolattukudy PE. Cloning of a novel constitutively expressed pectate lyase gene pelB from Fusarium solani f. sp. pisi (Nectria haematococca, mating type VI) and characterization of the gene product expressed in Pichia pastoris. J Bacteriol 1995; 177:7070-7. [PMID: 8522511 PMCID: PMC177583 DOI: 10.1128/jb.177.24.7070-7077.1995] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Since plant-pathogenic fungi must penetrate through pectinaceous layers of the host cell wall, pectin-degrading enzymes are thought to be important for pathogenesis. Antibodies prepared against a pectin-inducible pectate lyase (pectate lyase A [PLA]) produced by a phytopathogenic fungus, Fusarium solani f. sp. pisi (Nectria haematococca, mating type VI), was previously found to protect the host from infection. The gene (pelA) and its cDNA were cloned and sequenced. Here we report the isolation of a new pectate lyase gene, pelB, from a genomic library of F. solani f. sp. pisi with the pelA cDNA as the probe. A 2.6-kb DNA fragment containing pelB and its flanking regions was sequenced. The coding region of pelB was amplified by reverse transcription-mediated PCR, using total RNA isolated from F. solani pisi culture grown in the presence of glucose as the sole carbon source. The predicted open reading frame of pelB would encode a 25.6-kDa protein of 244 amino acids which has 65% amino acid sequence identity with PLA from F. solani f. sp. pisi but no significant homology with other pectinolytic enzymes. The first 16 amino acid residues at the N terminus appeared to be a signal peptide. The pelB cDNA was expressed in Pichia pastoris, yielding a pectate lyase B (PLB) which was found to be a glycoprotein of 29 kDa. PLB was purified to homogeneity by using a two-step procedure involving ammonium sulfate precipitation followed by Superdex G75 gel filtration chromatography. Purified PLB showed optimal lyase activity at pH 10.0. A rapid drop in the viscosity of the substrate and Mono Q anion-exchange chromatography of the products generated by the lyase showed that PLB cleaved polygalacturonate chains in an endo fashion. Western blotting (immunoblotting) with antibodies raised against PLA showed that PLB and PLA are immunologically related to each other. The 5' flanking regions of both pelA and pelB were translationally fused to the beta-glucuronidase gene and introduced into F. solani f. sp. pisi, and beta-glucuronidase activities of the transformants were measured. Expression of the marker gene by the transformants showed that pelA expression is induced by pectin and repressed by glucose, whereas expression of pelB is constitutive and is not subject to glucose repression. Reverse transcription-mediated PCR showed that both pelA and pelB are expressed when F. solani f. sp. pisi infects pea epicotyl.
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Affiliation(s)
- W Guo
- Neurobiotechnology Center, Ohio State University, Columbus 43210, USA
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17
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Ho MC, Whitehead MP, Cleveland TE, Dean RA. Sequence analysis of the Aspergillus nidulans pectate lyase pelA gene and evidence for binding of promoter regions to CREA, a regulator of carbon catabolite repression. Curr Genet 1995; 27:142-9. [PMID: 7788717 DOI: 10.1007/bf00313428] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The nucleic acid and deduced amino-acid sequences of the pectate lyase gene (pelA) from Aspergillus nidulans are presented. The pelA gene contains two short introns, 68 and 49 bp in length, and encodes a peptide of 326 amino acids. Five transcriptional start sites are clustered between 65 and 79 bp upstream of the start codon as determined by primer extension. Comparison of the amino-acid sequences of pectate or pectin lyases from bacteria, fungi and plants revealed less than 30% overall identity. However, five regions within these enzymes, in particular domains associated with the active site, are highly conserved with amino-acid similarities greater than 50%. Phylogenetic analysis using the principle of parsimony (PAUP 3.1.1) showed that pelA is most closely related to pectate lyases from plants rather than pectin lyases from other fungi. Previously, pelA was shown to be induced by polygalacturonic acid and repressed in the presence of preferred carbon sources, such as glucose. Gel mobility shift analysis indicates that a PstI-SphI fragment from the pelA promoter binds to a fusion protein composed of the N-terminal part of CREA, a protein involved in carbon catabolite repression, and glutathione-S-transferase. This result suggests CREA may contribute to the regulation of pelA expression.
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Affiliation(s)
- M C Ho
- Department of Plant Pathology and Physiology, Clemson University, SC 29634, USA
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18
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Yang G, Turgeon BG, Yoder OC. Toxin-deficient mutants from a toxin-sensitive transformant of Cochliobolus heterostrophus. Genetics 1994; 137:751-7. [PMID: 8088521 PMCID: PMC1206035 DOI: 10.1093/genetics/137.3.751] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Tox1 is the only genetic element identified which controls production of T-toxin, a linear polyketide involved in the virulence of Cochliobolus heterostrophus to its host plant, corn. Previous attempts to induce toxin-deficient (Tox-) mutants, using conventional mutagenesis and screening procedures, have been unsuccessful. As a strategy to enrich for Tox- mutants, we constructed a Tox1+ strain that carried the corn T-urf13 gene (which confers T-toxin sensitivity) fused to a fungal mitochondrial signal sequence; the fusion was under control of the inducible Aspergillus nidulans pelA promoter which, in both A. nidulans and C. heterostrophus, is repressed by glucose and induced by polygalacturonic acid (PGA). We expected that a transformant carrying this construction would be sensitive to its own toxin when the T-urf13 gene was expressed. Indeed, the strain grew normally on medium containing glucose but was inhibited on medium containing PGA. Conidia of this strain were treated with ethylmethanesulfonate and plated on PGA medium. Among 362 survivors, 9 were defective in T-toxin production. Authenticity of each mutant was established by the presence of the transformation vector, proper mating type, and a restriction fragment length polymorphism tightly linked to the Tox1+ locus. Progeny of each mutant crossed to a Tox1+ tester segregated 1:1 (for wild type toxin production vs. no or reduced toxin production), indicating a single gene mutation in each case. Progeny of each mutant crossed to a Tox1- tester segregated 1:1 (for no toxin production vs. no or reduced toxin production) indicating that each mutation mapped at the Tox1 locus. Availability of Tox- mutants will permit mapping in the Tox1 region without interference from a known Tox1 linked translocation breakpoint.
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Affiliation(s)
- G Yang
- Department of Plant Pathology, Cornell University, Ithaca, New York 14853
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19
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Kubicek CP, Messner R, Gruber F, Mach RL, Kubicek-Pranz EM. The Trichoderma cellulase regulatory puzzle: from the interior life of a secretory fungus. Enzyme Microb Technol 1993; 15:90-99. [PMID: 7763457 DOI: 10.1016/0141-0229(93)90030-6] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Novel applications for cellulases have reinitiated interest in the regulation of production of these enzymes by the soft rot fungus Trichoderma reesei and related species. This paper reviews the current state of knowledge concerning the question "How can insoluble molecules like cellulose initiate their own breakdown by a microorganism?" The evidence available--based on biochemical as well as molecular biological approaches--favors a model in which conidial bound cellobiohydrolases carry out a first exo-exo-wise attack on the cellulose molecule. The disaccharides so formed (cellobiose, alpha-cellobiono-1,5-lactone) are then taken up by the mycelia and promote further cellulase biosynthesis. Evidence available suggests that they are further metabolized to, rather than being, the "true" inducer. Speculations on the nature of the inducer are presented. The roles of the beta-glucosidases of Trichoderma in this process are discussed. The pathway of cellulase secretion is discussed on the basis of electron microscopical as well as gene sequence information.
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Affiliation(s)
- C P Kubicek
- Abteilung für Mikrobielle Biochemie, Institut für Biochemische Technologie und Mikrobiologie, Vienna, Austria
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20
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González-Candelas L, Kolattukudy PE. Isolation and analysis of a novel inducible pectate lyase gene from the phytopathogenic fungus Fusarium solani f. sp. pisi (Nectria haematococca, mating population VI). J Bacteriol 1992; 174:6343-9. [PMID: 1400187 PMCID: PMC207579 DOI: 10.1128/jb.174.20.6343-6349.1992] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A pectate lyase produced by Fusarium solani f. sp. pisi (Nectria haematococca, mating population VI) was previously shown to be essential for host infection (M. S. Crawford and P. E. Kolattukudy, Arch. Biochem. Biophys. 258:196-205, 1987). Pectate lyase genes have not been cloned from any phytopathogenic fungi. A gene, designated pelA, encoding an inducible pectate lyase was isolated from F. solani f. sp. pisi. A probe was synthesized by polymerase chain reaction with oligonucleotide primers based on the known amino acid sequences of two regions of the mature protein and first-strand cDNA as template. Both cDNA and the gene were isolated and sequenced. That the cloned cDNA represents the previously purified pectate lyase is shown by the complete match of the sequences of the N-terminal 38 amino acid residues and the 20 amino acid residues of an internal peptide with the sequence deduced from the cDNA sequence. This lyase sequence shows little homology to those of other pectolytic enzymes. The pelA gene shows standard characteristics with respect to promoter, intron, and polyadenylation sequences. As determined by primer extension and nuclease S1 analysis of the origin of the transcription, there are multiple initiation sites clustered in a region of 12 nucleotides located about 55 bp upstream of the start codon. Northern (RNA) blot analysis showed a single band of mRNA at about 1 kb. The pelA gene mRNA was detected only when F. solani f. sp. pisi was grown with pectin, and there was no detectable transcript accumulation when the fungus was grown with glucose as the sole carbon source. When both carbon sources were present, the pelA gene was transcribed only after glucose was completely depleted, indicating carbon catabolite repression. Moreover, the levels of transcription decreased rapidly prior to maximal enzyme accumulation, suggesting a mechanism of self catabolite repression.
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21
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Bussink HJ, Buxton FP, Fraaye BA, de Graaff LH, Visser J. The polygalacturonases of Aspergillus niger are encoded by a family of diverged genes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 208:83-90. [PMID: 1511691 DOI: 10.1111/j.1432-1033.1992.tb17161.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Aspergillus niger produces several polygalacturonases that, with other enzymes, are involved in the degradation of pectin. One of the two previously characterized genes coding for the abundant polygalacturonases I and II (PGI and PGII) found in a commercial pectinase preparation was used as a probe to isolate five more genes by screening a genomic DNA library in phage lambda EMBL4 using conditions of moderate stringency. The products of these genes were detected in the culture medium of Aspergillus nidulans transformants on the basis of activity measurements and Western-blot analysis using a polyclonal antibody raised against PGI. These transformants were, with one exception, constructed using phage DNA. A. nidulans transformants secreted high amounts of PGI and PGII in comparison to the previously characterized A. niger transformants and a novel polygalacturonase (PGC) was produced at high levels by A. nidulans transformed with the subcloned pgaC gene. This gene was sequenced and the protein-coding region was found to be interrupted by three introns; the different intron/exon organization of the three sequenced A. niger polygalacturonase genes can be explained by the gain or loss of two single introns. The pgaC gene encodes a putative 383-amino-acid prepro-protein that is cleaved after a pair of basic amino acids and shows approximately 60% amino acid sequence similarity to the other polygalacturonases in the mature protein. The N-terminal amino acid sequences of the A. niger polygalacturonases display characteristic amino acid insertions or deletions that are also observed in polygalacturonases of phytopathogenic fungi. In the upstream regions of the A. niger polygalacturonase genes, a sequence of ten conserved nucleotides comprising a CCAAT sequence was found, which is likely to represent a binding site for a regulatory protein as it shows a high similarity to the yeast CYC1 upstream activation site recognized by the HAP2/3/4 activation complex.
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Affiliation(s)
- H J Bussink
- Department of Genetics, Wageningen Agricultural University, The Netherlands
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22
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Kornstein LB, Gaiso ML, Hammell RL, Bartelt DC. Cloning and sequence determination of a cDNA encoding Aspergillus nidulans calmodulin-dependent multifunctional protein kinase. Gene 1992; 113:75-82. [PMID: 1563634 DOI: 10.1016/0378-1119(92)90671-b] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A partial cDNA encoding Aspergillus nidulans calmodulin-dependent multifunctional protein kinase (ACMPK) was isolated from a lambda ZAP expression library by immunoselection using monospecific polyclonal antibodies to the enzyme. The sequence of both strands of the cDNA (CMKa) was determined. The deduced amino acid (aa) sequence contained all eleven consensus domains found in serine/threonine protein kinases [Hanks et al., Science 241 (1988) 42-52], as well as a putative calmodulin-binding domain. The cDNA contained an intron, lacked an in-frame start codon, and was not polyadenylated. A full-length copy of CMKa was subsequently isolated from a lambda gt10 library of A. nidulans cDNA using a restriction fragment of the first clone as a probe. It contained an in-frame start codon, an open reading frame (ORF) of 1242 bp and was polyadenylated. The ORF encoded a protein of 414 aa residues with an M(r) of 46,895 and an isoelectric point pI = 6.4. These values are in good agreement with that observed for the native enzyme [Bartelt et al., Proc. Natl. Acad. Sci. USA 85 (1988) 3279-3283]. When aligned to optimize homology, 29% of the predicted aa sequence of ACMPK is identical to that of the alpha-subunit of rat brain calmodulin-dependent protein kinase II. ACMPK shares 40 and 44% identity in aa sequence with YCMK1 and YCMK2, respectively, two Ca2+/calmodulin-dependent protein kinases recently cloned from Saccharomyces cerevisiae [Pausch et al., EMBO J. 10 (1991) 1511-1522]. Results of Southern analysis of restriction digests of genomic DNA indicate that ACMPK is encoded by a single-copy gene.
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Affiliation(s)
- L B Kornstein
- Department of Biological Sciences, St. John's University Jamaica, NY 11439
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23
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Riou C, Fraissinet-Tachet L, Freyssinet G, Fèvre M. Secretion of pectic isoenzymes bySclerotinia sclerotiorum. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05214.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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24
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Analysis of the creA gene, a regulator of carbon catabolite repression in Aspergillus nidulans. Mol Cell Biol 1991. [PMID: 1922072 DOI: 10.1128/mcb.11.11.5701] [Citation(s) in RCA: 238] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The complete nucleotide sequence derived from a genomic clone and two cDNA clones of the creA gene of Aspergillus nidulans is presented. The gene contains no introns. The derived polypeptide of 415 amino acids contains two zinc fingers of the C2H2 class, frequent S(T)PXX motifs, and an alanine-rich region indicative of a DNA-binding repressor protein. The amino acid sequence of the zinc finger region has 84% similarity to the zinc finger region of Mig1, a protein involved in carbon catabolite repression in yeast cells, and it is related both to the mammalian Egr1 and Egr2 proteins and to the Wilms' tumor protein. A deletion removing the creA gene was obtained, by using in vitro techniques, in both a heterokaryon and a diploid strain but was unobtainable in a pure haploid condition. Evidence is presented suggesting that the phenotype of such a deletion, when not complemented by another creA allele, is leaky lethality allowing limited germination of the spore but not colony formation. This phenotype is far more extreme than that of any of the in vivo-generated mutations, and thus either the gene product may have an activator activity as well as a repressor function or some residual repressor function may be required for full viability.
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25
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Dowzer CE, Kelly JM. Analysis of the creA gene, a regulator of carbon catabolite repression in Aspergillus nidulans. Mol Cell Biol 1991; 11:5701-9. [PMID: 1922072 PMCID: PMC361941 DOI: 10.1128/mcb.11.11.5701-5709.1991] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The complete nucleotide sequence derived from a genomic clone and two cDNA clones of the creA gene of Aspergillus nidulans is presented. The gene contains no introns. The derived polypeptide of 415 amino acids contains two zinc fingers of the C2H2 class, frequent S(T)PXX motifs, and an alanine-rich region indicative of a DNA-binding repressor protein. The amino acid sequence of the zinc finger region has 84% similarity to the zinc finger region of Mig1, a protein involved in carbon catabolite repression in yeast cells, and it is related both to the mammalian Egr1 and Egr2 proteins and to the Wilms' tumor protein. A deletion removing the creA gene was obtained, by using in vitro techniques, in both a heterokaryon and a diploid strain but was unobtainable in a pure haploid condition. Evidence is presented suggesting that the phenotype of such a deletion, when not complemented by another creA allele, is leaky lethality allowing limited germination of the spore but not colony formation. This phenotype is far more extreme than that of any of the in vivo-generated mutations, and thus either the gene product may have an activator activity as well as a repressor function or some residual repressor function may be required for full viability.
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Affiliation(s)
- C E Dowzer
- Department of Genetics, University of Adelaide, Australia
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26
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Kusters-van Someren MA, Harmsen JA, Kester HC, Visser J. Structure of the Aspergillus niger pelA gene and its expression in Aspergillus niger and Aspergillus nidulans. Curr Genet 1991; 20:293-9. [PMID: 1934134 DOI: 10.1007/bf00318518] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Aspergillus niger pectin lyases are encoded by a multigene family. The complete nucleotide sequence of the pectin lyase PLA-encoding gene pelA has been determined. Comparison of the deduced amino acid sequence with the deduced amino acid sequence of the other characterized pectin lyase, PLD, shows that the proteins share 69% amino acid identity. When grown on media with pectin as the sole carbon source, A. niger transformants containing multiple copies of the pelA gene show raised mRNA levels and overexpression of the gene product PLA compared with the wild-type strain. PLA was purified and characterized. In A. nidulans transformants PLA is also produced in medium containing a high concentration of glucose and no pectin.
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27
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Bussink HJ, Brouwer KB, de Graaff LH, Kester HC, Visser J. Identification and characterization of a second polygalacturonase gene of Aspergillus niger. Curr Genet 1991; 20:301-7. [PMID: 1934135 DOI: 10.1007/bf00318519] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The filamentous fungus Aspergillus niger produces several endopolygalacturonases that are involved in the degradation of pectin. PGI, the enzyme representing the second most abundant activity in a commercial enzyme preparation, was further characterized and the corresponding gene was isolated. The nucleotide sequence of the pgaI gene was determined and the protein coding region was found to be interrupted by two short introns, one of which has a unusual donor splice site. The deduced 368 amino acids long protein with a putative prepropeptide of 31 amino acids shows 60% sequence identity to PGII in the mature protein. PGI overproducing A. niger strains were obtained by cotransformation with the cloned gene.
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Affiliation(s)
- H J Bussink
- Department of Genetics, Agricultural University, Wageningen, The Netherlands
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28
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Liao CH. Cloning of pectate lyase gene pel from Pseudomonas fluorescens and detection of sequences homologous to pel in Pseudomonas viridiflava and Pseudomonas putida. J Bacteriol 1991; 173:4386-93. [PMID: 1906062 PMCID: PMC208100 DOI: 10.1128/jb.173.14.4386-4393.1991] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pectate lyase (PL) depolymerizes pectin and other polygalacturonates (PGAs) and is thought to play a role in bacterial invasion of plants. Production of PL by the soft-rotting pathogen Pseudomonas fluorescens CY091 is regulated by Ca2+. In the presence of Ca2+, this bacterium constitutively synthesizes PL in media containing glucose, glycerol, or PGA and excretes over 87% of total PL into culture fluids. In the absence of Ca2+, the organism fails to use PGA as a carbon source and produces very low levels of PL in media containing glucose or glycerol. Of the small amount of PL produced by the bacterium in Ca(2+)-deficient media, over 78% was detected within the cells, indicating that Ca2+ is critical not only for the production but also for the secretion of PL. The pel gene, encoding an alkaline PL (pI 10.0, Mr 41,000) was cloned and located on the overlapping region of a 4.3-kb SalI and a 7.1-kb EcoRI fragment. The 7.1-kb EcoRI fragment appears to contain a promoter for pel gene expression. A 1.7-kb SalI-XhoI subfragment of the 4.3-kb SalI fragment was cloned into pUC18 to give pROTM2. Escherichia coli cells carrying pROTM2 produce 50 to 100 times more PL than do cells carrying other pectolytic constructs. Production of PL by E. coli (pROTM2) was not affected by carbon sources or by Ca2+. The pI and Mr of PL from E. coli corresponded to values for its counterpart from P. fluorescens. A 0.7-kb BglII-ClaI fragment encoding the pel structural sequence was used to detect pel homologs in various species of fluorescent pseudomonads. Homologous sequences were observed in 10 of 11 strains of P. fluorescens, P. viridiflava, and P. putida. The pel gene in fluorescent pseudomonads is well conserved and may exist and remain repressed in certain strains or species which exhibit nonpectolytic phenotypes under laboratory conditions.
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Affiliation(s)
- C H Liao
- Eastern Regional Research Center, U.S. Department of Agriculture, Philadelphia, Pennsylvania 19118
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29
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Bussink HJ, Buxton FP, Visser J. Expression and sequence comparison of the Aspergillus niger and Aspergillus tubigensis genes encoding polygalacturonase II. Curr Genet 1991; 19:467-74. [PMID: 1878999 DOI: 10.1007/bf00312738] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The structure and expression of the polygalacturonase-encoding pgaII genes of two recently recognized species, Aspergillus niger and Aspergillus tubigensis, was investigated. While the structure of the pgaII genes is very similar, showing 83% DNA sequence identity and 94% identity at the amino acid level, they have diverged significantly. The NH2-terminal sequence suggests that these PGs are made as pre pro-proteins and the secretory propeptide of the PGII precursors shows sequence homology with some other fungal pro-peptides. The expression of the pgaII genes is strongly regulated by the carbon source and the A. tubigensis gene is expressed and regulated in A. niger transformants. The low similarity of the fungal PGs with those of bacterial and plant origin is discussed in relation to the possible functional role of specific amino acids.
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Affiliation(s)
- H J Bussink
- Department of Genetics, Agricultural University, Wageningen, The Netherlands
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30
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Harmsen JA, Kusters-van Someren MA, Visser J. Cloning and expression of a second Aspergillus niger pectin lyase gene (pelA): indications of a pectin lyase gene family in A. niger. Curr Genet 1990; 18:161-6. [PMID: 2225145 DOI: 10.1007/bf00312604] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using the previously cloned Aspergillus niger N756 pectin lyase D gene as a probe, the corresponding pelD gene has been isolated from a genomic library of the laboratory strain A. niger N400. This gene encodes PLD, previously described as PLI, which is one of the two major pectin lyases isolated from the commercial pectinase preparation Ultrazym. Heterologous hybridization of the A. niger N400 genomic library with the pelD gene led to the isolation of another five genes: pelA, B, C, E, and F. These genes differ in their hybridization patterns with probes containing either the entire pelD gene, or 5' or 3' parts thereof. By partial sequencing, and expression in an A. niger transformant containing multiple copies of the pelA gene, we show that this gene, which hybridizes strongest with the pelD gene, encodes the other major pectin lyase from Ultrazym, PLII.
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Affiliation(s)
- J A Harmsen
- Department of Genetics, Agricultural University, Wageningen, The Netherlands
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31
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Isolation and characterization of pectin inducible cDNA clones from the phytopathogenic fungus Fusarium moniliforme. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/s0953-7562(09)80665-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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32
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Wing RA, Yamaguchi J, Larabell SK, Ursin VM, McCormick S. Molecular and genetic characterization of two pollen-expressed genes that have sequence similarity to pectate lyases of the plant pathogen Erwinia. PLANT MOLECULAR BIOLOGY 1990; 14:17-28. [PMID: 1983191 DOI: 10.1007/bf00015651] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A set of cDNAs that are expressed in tomato anthers were isolated. We further characterized two of these cDNAs (LAT56 and LAT59) and their corresponding genomic clones. LAT56 and LAT59 show low levels of steady-state mRNA in immature anthers and maximal levels in mature anthers and pollen. The LAT56 and LAT59 genes are single-copy in the tomato genome, and are linked on chromosome 3, approximately 5 cM apart. Although these cDNAs did not cross-hybridize, their deduced protein sequences (P56 and P59) have 54% amino acid identity. The LAT56 and LAT59 genes each have two introns, but they are located in non-homologous positions. P56 and P59 show significant protein sequence similarity to pectate lyases of plant pathogenic bacteria. The similarity of P56 and P59 to the bacterial pectate lyases is equivalent to the homology described for different pectate lyase sequences of the genus Erwinia. We suggest that the pollen expression of LAT56 and LAT59 might relate to a requirement for pectin degradation during pollen tube growth.
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Affiliation(s)
- R A Wing
- Plant Gene Expression Center, USDA/ARS-UC-Berkeley, Albany 94710
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33
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Dean RA, Timberlake WE. Production of cell wall-degrading enzymes by Aspergillus nidulans: a model system for fungal pathogenesis of plants. THE PLANT CELL 1989; 1:265-273. [PMID: 2535501 PMCID: PMC159759 DOI: 10.1105/tpc.1.3.265] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The cell wall-degrading enzymes polygalacturonase and pectate lyase have been suggested to be crucial for penetration and colonization of plant tissues by some fungal pathogens. We have found that Aspergillus nidulans (= Emericella nidulans), a saprophytic Ascomycete, produces levels of these enzymes equal to those produced by soft-rotting Erwinia species. Induction of polygacturonase and pectate lyase in A. nidulans requires substrate and is completely repressed by glucose. Surprisingly, inoculation of excised plant tissues with A. nidulans conidia leads to formation of necrotic, water-soaked lesions within which the organism sporulates. Thus, A. nidulans has phytopathogenic potential. The release of glucose and other sugars from wounded tissues may repress pectolytic enzyme production and limit disease development. Therefore, we tested creA204, a mutation that relieves glucose repression of some A. nidulans carbon utilization enzymes, for its effect on production of pectolytic enzymes. creA204 failed to relieve catabolite repression of polygalacturonase or pectate lyase and had no effect on disease severity.
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Affiliation(s)
- R A Dean
- Department of Plant Pathology, University of Georgia, Athens 30602
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34
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Dean RA, Timberlake WE. Production of cell wall-degrading enzymes by Aspergillus nidulans: a model system for fungal pathogenesis of plants. THE PLANT CELL 1989. [PMID: 2535501 DOI: 10.2307/3869006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The cell wall-degrading enzymes polygalacturonase and pectate lyase have been suggested to be crucial for penetration and colonization of plant tissues by some fungal pathogens. We have found that Aspergillus nidulans (= Emericella nidulans), a saprophytic Ascomycete, produces levels of these enzymes equal to those produced by soft-rotting Erwinia species. Induction of polygacturonase and pectate lyase in A. nidulans requires substrate and is completely repressed by glucose. Surprisingly, inoculation of excised plant tissues with A. nidulans conidia leads to formation of necrotic, water-soaked lesions within which the organism sporulates. Thus, A. nidulans has phytopathogenic potential. The release of glucose and other sugars from wounded tissues may repress pectolytic enzyme production and limit disease development. Therefore, we tested creA204, a mutation that relieves glucose repression of some A. nidulans carbon utilization enzymes, for its effect on production of pectolytic enzymes. creA204 failed to relieve catabolite repression of polygalacturonase or pectate lyase and had no effect on disease severity.
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Affiliation(s)
- R A Dean
- Department of Plant Pathology, University of Georgia, Athens 30602
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