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PubMed1997

Molecular genetic evidence for the involvement of a specific polygalacturonase, P2c, in the invasion and spread of Aspergillus flavus in cotton bolls.

Isolates of Aspergillus flavus can be differentiated based on production of the polygalacturonase P2c. One group of isolates produces P2c, whereas the other group does not. In general, the group that produces P2c causes more damage and spreads to a greater extent in cotton bolls than those isolates that do not produce P2c. To determine whether P2c contributes to disease, the expression of pecA, the gene previously determined to encode P2c, was genetically altered. Adding the pecA gene to a strain previously lacking the gene resulted in the ability to cause significantly more damage to the intercarpellary membrane and the ability spread to a greater extent within the adjacent locule compared to the abilities of a control transformant. Conversely, eliminating the expression of pecA by targeted disruption caused a significant reduction in aggressiveness compared to that of a nondisrupted control transformant. These results provide direct evidence that P2c contributes to the invasion and spread of A. flavus during infection of cotton bolls. However, other factors not evaluated in this study also contribute to aggressiveness.

Aspergillus flavus↗
PubMed1985

Evidence that polygalacturonase is a virulence determinant in Erwinia carotovora.

Polygalacturonase (PG) was purified from Erwinia carotovora EC. A hybrid cosmid, pSH711, that encodes PG activity but not pectate lyase activity was identified from an E. carotovora genomic library by an immunological screening method. A cell extract of Escherichia coli cells containing pSH711 was able to produce plant tissue maceration when spotted on carrot, potato, or turnip slices. In addition, the E. coli strain containing this plasmid was able to macerate carrot, potato, and turnip slices. Our results suggest that PG plays an important role in soft-rot disease.

Cloning, Molecular↗
PubMed1997

Control of polygalacturonase synthesis in Fusarium oxysporum f.sp. radicis lycopersici.

Genetic control of polygalacturonase (PG) activity from Fusarium oxysporum f.sp. radicis lycopersici was analyzed on pectin and glucose cultures. One exopolygalacturonase from F. oxysporum f.sp. radicis lycopersici was strongly induced, in stationary culture, when the fungus was grown on apple pectin, while on glucose no extracellular PG activity could be detected. Although SDS-PAGE detected the presence of a putative PG band (66 kDa) in both conditions, specific antibodies obtained against the purified PG only detected it in PG-inducing conditions, that is to say, when apple pectin was used as the carbon source. Northern blot analysis of RNA of two isolates of F. oxysporum f.sp. radicis lycopersici (r6 and r2) confirmed that this regulation of PG synthesis was exerted at the transcriptional level. Only one single mRNA species of around 1400 nucleotides was detected on the cultures containing pectin and was absent in glucose-grown cultures. Southern blot analysis of genomic DNA indicated that pg gene seems to be present in a single copy in the genomes of F. oxysporum f.sp. radicis lycopersici r6 and r2 and Fusarium oxysporum f.sp. lycopersici, showing similar hybridization patterns in all species. The partial sequence of this pg gene from F. oxysporum f.sp. radicis lycopersici r6, which is also reported, showed high similarity to diverse PGs already reported. Exopolygalacturonase of F. oxysporum f.sp. radicis lycopersici r6 is heavily glycosylated; its deglycosylated form had a molecular mass of 50 kDa.

Amino Acid Sequence↗
PubMed2001

The role of polygalacturonase-inhibiting proteins (PGIPs) in defense against pathogenic fungi.

Polygalacturonase-inhibiting proteins (PGIPs) are extracellular plant proteins capable of inhibiting fungal endopolygalacturonases (PGs). Plants have evolved different PGIPs with specific recognition abilities against the many PGs produced by fungi. The genes encoding PGIPs are organized into families, and different members of each family may encode proteins with nearly identical characteristics but different specificities and regulation. PGIPs are typically induced by pathogen infection and stress-related signals. The recognition ability of PGIPs resides in their LRR (leucine-rich repeat) structure, where solvent-exposed residues in the beta-strand/beta-turn motifs of the LRRs are determinants of specificity. Manipulation of the primary structure of PGIPs is expected to generate more efficient PGIPs with novel recognition specificities to protect crop plants against pathogens.

Amino Acid Sequence↗
PubMed2006

Patterns of expansion and expression divergence in the plant polygalacturonase gene family.

BACKGROUND: Polygalacturonases (PGs) belong to a large gene family in plants and are believed to be responsible for various cell separation processes. PG activities have been shown to be associated with a wide range of plant developmental programs such as seed germination, organ abscission, pod and anther dehiscence, pollen grain maturation, fruit softening and decay, xylem cell formation, and pollen tube growth, thus illustrating divergent roles for members of this gene family. A close look at phylogenetic relationships among Arabidopsis and rice PGs accompanied by analysis of expression data provides an opportunity to address key questions on the evolution and functions of duplicate genes. RESULTS: We found that both tandem and whole-genome duplications contribute significantly to the expansion of this gene family but are associated with substantial gene losses. In addition, there are at least 21 PGs in the common ancestor of Arabidopsis and rice. We have also determined the relationships between Arabidopsis and rice PGs and their expression patterns in Arabidopsis to provide insights into the functional divergence between members of this gene family. By evaluating expression in five Arabidopsis tissues and during five stages of abscission, we found overlapping but distinct expression patterns for most of the different PGs. CONCLUSION: Expression data suggest specialized roles or subfunctionalization for each PG gene member. PGs derived from whole genome duplication tend to have more similar expression patterns than those derived from tandem duplications. Our findings suggest that PG duplicates underwent rapid expression divergence and that the mechanisms of duplication affect the divergence rate.

Arabidopsis↗
PubMed1996

Purification and characterization of three extracellular protopectinases with polygalacturonase activities from Trichosporon penicillatum.

In a culture filtrate of Trichosporan penicillatum B2, which is a gamma-ray irradiation mutant induced from T. penicillatum SNO3, we found three kinds of pectin-releasing enzymes, protopectinases SE1, SE2, and SE3, that have endo-polygalacturonase activity. These enzymes were purified to homogeneity with cation-exchange and size exclusion chromatographies. The major PPase in the culture filtrate was PPase SE1, which accounted for 75% of total activities in the culture filtrate, and the two others were 0.15% (PPase SE2) and 0.007% (PPase SE3). Their molecular masses were approximately 41, 41, and 42 kDa on SDS-PAGE, respectively. They had similar enzymatic properties but different PPase activity and pH- and thermo-stability. Antibody against PPase S, which is produced by strain SNO3, inhibited the activities of PPase SE1, SE2, and SE3. However PPase SE1 was completely inhibited by treatment with the anti-PPase S antibody, but the activities of PPases SE2 and SE3 remained at 20 and 50% of the original activity, respectively.

Amino Acid Sequence↗
PubMed1999

Purification and characterization of an endo-polygalacturonase from a mutant of Saccharomyces cerevisiae.

An extracellular endo-polygalacturonase (PGase) produced by a mutant of Saccharomyces cerevisiae was isolated. The enzyme was regarded, immunologically, as a PGase belonging to the Kluyveromyces marxianus group. The enzyme had properties similar to the PGase from K. marxianus in heat and pH stability, and N-terminal amino acid sequence. However, the enzyme showed different properties in optimum pH and temperature, molecular weight, and reactivity in antiserum against PGase from K. marxianus, indicating that the enzyme has a different molecular structure from the PGase from K. marxianus.

Antibodies, Monoclonal↗
PubMed2000

Purification and characterization of an endo-polygalacturonase. From Aspergillus awamori.

An extracellular endo-polygalacturonase (PGase) produced by Aspergillus awamori IFO 4033 was isolated from the culture filtrate. The enzyme was purified to a homogeneous preparation with cation-exchange and size-exclusion chromatographies. Its properties were investigated, comparing them with that of recombinant pgx2 gene product, a PGase having protopectinase activity. This enzyme was a monomeric protein of 41 kDa, with an isoelectric point of pH 6.1. The characteristics of this PGase substantially coincide, with that of recombinant pgx2 gene product, and the PGase is assumed to be native pgx2 gene product. The production of PGase-X2 was confirmed to be regulated by ambient pHs.

Amino Acid Sequence↗
PubMed2005

Characteristics of wines made by Saccharomyces mutants which produce a polygalacturonase under wine-making conditions.

Wines by yeast mutants producing polygalacturonase in high glucose concentration, from Saccharomyces wine-making strains, had higher filterability and more concentrated anthocyanin contents than that of their parent strains. These results suggest that the clarification process was improved at a lower cost by the low viscosity and that high-quality wines result from the increase in the anthocyanin contents.

Filtration↗
PubMed2005

Cold-active polygalacturonase from psychrophilic-basidiomycetous yeast Cystofilobasidium capitatum strain PPY-1.

We purified and characterized a cold-active polygalacturonase (PG) from the extracellular fraction of Cystofilobasidium capitatum strain PPY-1. The purified PG from strain PPY-1 has a molecular mass of about 44 kDa, and exhibited high activity at 0 degrees C, although its optimum temperature was 45 degrees C. Although the Km value for polygalacturonate as a substrate at 45 degrees C was found to be 11.2 mg/ml, it decreased gradually with decreasing temperature, and it was 0.66 mg/ml at 0 degrees C. Moreover, its cleavage pattern was of the endo-type. These findings might indicate that PG from strain PPY-1 is a novel type of cold-active endo-PG that is able to degrade pectin compounds at low temperatures.

Amino Acid Sequence↗
PubMed2006

Characterization of cold- and high-pressure-active polygalacturonases from a deep-sea yeast, Cryptococcus liquefaciens strain N6.

A deep-sea yeast, Cryptococcus liquefaciens strain N6, produces two polygalacturonases, p36 and p40 (N6-PGases). These N6-PGases were highly active at 0-10 degrees C in comparison to a PGase from Aspergillus japonicus. The hydrolytic activity of these N6-PGases remained almost unchanged up to a hydrostatic pressure of 100 MPa at 24 degrees C with a very small activation volume of -1.1 ml/mol. At 10 degrees C, however, the activation volume increased to 3.3 or 5.4 ml/mol (p36 and p40, respectively), suggesting that the enzyme-substrate complexes can expand at their transition states. We speculate that such a volume expansion upon forming the enzyme-substrate complexes contributes to decreasing the activation energy for hydrolysis. This can account for the high activity of N6-PGases at low-temperature.

Cold Temperature↗
PubMed2002

Production, purification, and characterization of a polygalacturonase from a new strain of Kluyveromyces marxianus isolated from coffee wet-processing wastewater.

A new high polygalacturonase (PG)-producing Kluyveromyces marxianus strain was isolated from coffee wet-processing wastewater. PG production in this strain is not repressed in the presence of 100 g/L of glucose and, being growth-associated, reached its maximum accumulation in the culture medium at the beginning of the stationary phase. Oxygen and galacturonic acid negatively regulated enzyme synthesis, and glucose as the carbon source afforded better enzyme yields than lactose. The data reported here show that this strain exhibits the highest index of PG production among the wild-type strains reported so far (18.8 U/mL). PG was readily purified by ion-exchange chromatography on SP-Sepharose FF. The activity corresponded to a single protein with an M(r) of 41.7kDa according to sodium dodecyl sulfatepolyacrylamide gel electrophoresis. The enzyme was stable in the pH range of 3.0-5.0 and displayed an optimal temperature of 55 degrees C; it showed a typical endosplitting way of substrate hydrolysis and exhibited a fair degree of activity on pectin with a high degree of esterification.

Carbon↗
PubMedDate not supplied

Evaluation of filamentous fungi and inducers for the production of endo-polygalacturonase by solid state fermentation.

Aspergillus oryzae CCT 3940, Aspergillus awamori NRRL 3112 and a Trichoderma sp.) were compared for their capacity to produce endo-polygalacturonase (endo-PG) in solid state fermentation. Maximum pectinolytic activity was reached in 72 h of growth, the best two fungal strains being A. niger T0005007-2 and A. oryzae CCT 3940. Three types of commercial purified pectin and four of unprocessed pectin (tangerine, orange, Tahiti lime and sweet lime rind) were used to assess the effect of pectin on the production of endo-PG by A. niger T0005007-2. Maximum pectinolytic activity was achieved using 6 and 10% (w/w) of purified pectin as inducer. Depending on the origin of the commercial pectin used as inducer, maximum endo-PG levels varied from 223 to 876 units per gram of dry medium (one endo-PG unit (U) was defined as the quantity of enzyme which caused a reduction in viscosity of 50% in a 1% w/v solution of pectin in 30 min), indicating that care should be taken when choosing this component of the medium. When the crude pectins were used as inducers at the same concentration as purified pectin, maximum endo-PG activities were 250-300 units/g. However, by increasing the amount of Tahiti lime rind to 50% (w/w) maximum endo-PG was 919 U/g, thus opening up the possibility of a low cost medium for endo-PG production.

Aspergillus↗
PubMed1995

Sequence of Asr2, a member of a gene family from Lycopersicon esculentum encoding chromosomal proteins: homology to an intron of the polygalacturonase gene.

Asr is a family of genes regulated by abscisic acid, stress and ripening in tomato. Asr2, a recently reported member of this family, has been further characterized through sequencing of a genomic clone. We report the sequencing of 2029 bp of Asr2, spanning its AT-rich (62%) upstream region with probable regulatory functions. This region displays several candidate TATA and CAAT boxes that might be involved in transcription initiation, as well as a motif similar to one previously reported to be responsible for induction by ABA. Apart from that, we found a 108-bp stretch from the 3' non-coding region which displays a high homology (92%) to a region within intron 6 of the polygalacturonase gene, which, like Asr2, is expressed in ripening tomato fruit. This striking similarity suggests the presence of either a conserved regulatory motif or an abundant mobile element.

Base Sequence↗
PubMedDate not supplied

[Inactivation of polygalacturonase in the process of growth of the yeast Saccharomyces pastorianus].

The effect of exogenous glucose addition on polygalacturonase (EC 3.2.1.15) activity in the culture medium of Saccharomyces pastorianus was studied. An rapid but transient decrease in the enzyme activity was observed after 9-12 h after adding glucose to the culture medium. This effect was not associated with protein degradation or modification in the spectrum of secreted proteins. Ethyl acetate appeared in the culture medium during this period.

Acetates↗
PubMedDate not supplied

[Activity of a proteinaceous polygalacturonase inhibitor in potato plants].

The activity of a protein inhibitor of polygalacturonase (PIPG) was studied in potato tubers during storage and in potato leaves and stems during vegetation. The activity of PIPG in tubers varied from between seasons. The activity of PIPG during dormancy changed depending on the storage stage and temperature. As a rule, it was higher in etiolated sprouts than in the tubers. The activity of PIPG was slightly higher in leaves of adult vegetating plants than in stems and decreased by the end of vegetation. These changes in the activity of PIPG are suggested to be associated with changes in the growth rate.

Enzyme Inhibitors↗
PubMed2000

Enhancement of polygalacturonase activity during auxin induced para nodulation and endorhizosphere colonization of Azospirillum in rice roots.

Effect of different auxins, namely, 2,4-dichlorophenoxyacetic acid (2,4-D), naphthalene acetic acid (NAA) and indole acetic acid (IAA) and Azospirillum brasilense bioinoculation on the enhancement of polygalacturonase (PG) activity in rice roots during para nodulation and endorhizosphere colonization of Azospirillum was studied under in vitro condition. It was observed that Azospirillum bioinoculation could augment PG activity of rice roots to a lesser extent without any root morphogenesis whereas auxin application together with Azospirillum bioinoculation enhanced PG activity of rice roots to a higher level which resulted in better root morphogenesis (para nodule) and endorhizosphere colonisation of A. brasilense. Among the three auxins tested, 2,4-D, even at lower concentration (0.5 ppm) enhanced the rice root PG activity, root morphogenesis and endorhizosphere colonization of Azospirillum while it was 2.0 ppm with NAA and variable with IAA. It is concluded that there is a positive correlation existing among PG activity, degree of root morphogenesis and endorhizosphere colonization of Azospirillum brasilense in rice roots and the degree of correlation is determined by the chemical composition, concentration and mode of action of the auxin utilised.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2004

[Relationship between ethylene and polygalacturonase in tomato fruits].

Ethylene and PG (polygalacturonase) are both key plant growth regulators in fruit ripening process. The expression of PG was markedly inhibited in either antisense ACS tomato (Lycopersicon esculentum cv. Lichun) where endogenous ethylene synthesis was suppressed, or in Nr mutant in which ethylene perception was severely damaged. Also, the PG activities in fruits of these mutants were significantly lower than that of wild-type tomato (Fig. 1B). PG gene expression was promoted in mature green tomato fruit by exogenous ethylene 100 microL/L treatment for 4 h, and was inhibited significantly in breaking tomato fruit after being treated with 1-MCP (1-methylcycloprane) 1 microL/L, a specific ethylene reception inhibitor. Ethylene production of antisense PG tomato fruit during 45-50 DAP was lower than that of wild-type tomato (Fig. 4), and the level of transcriptional expression of both the ethylene receptor gene LeETR4 and the ethylene response factor gene LeERF2 were lower in this transgenic tomato fruit (Fig. 5). Ethylene production and the expression of LeETR4 and LeERF2 were both promoted by treatments with D-GA 100 mg/L, a product of enzymatic degradation of PG, in immature tomato fruit (Fig. 6 and Fig. 7). The relationship of PG and ethylene in tomato fruit in this study provided forceful evidences to support the mechanism by which PG and ethylene synergistically regulated climacteric fruit ripening and softening.

Base Sequence↗