Polygalacturonase from <i>Rhizopus stolonifer,</i> an Elicitor of Casbene Synthetase Activity in Castor Bean (<i>Ricinus communis</i> L.) Seedlings

Lee, Sung-Chul; West, Charles A.

doi:10.1104/pp.67.4.633

Cited by 115 publications

(32 citation statements)

References 22 publications

(23 reference statements)

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“…Because of these problems, we established a protoplast system from carrot and measured the elicitor-induced 45Ca2+ influx. In contrast to suspension-cultured cells, protoplasts very often do not retain their responsiveness to elicitors because of the effects of endogenous elicitors and the effects of the fungal hydrolases used for the preparation of protoplasts; it has been shown for Ricinus that the enzymic hydrolysis of the wall mimics a fungal infection and leads to an induction of casbene synthesis (Lee and West, 1983). As already described in a previous paper (Schnitzler and Seitz, 1989), carrot protoplasts show the same response to the elicitor from P. aphanidermatum as the respective suspension-cultured cells.…”

Section: Discussionmentioning

confidence: 99%

Elicitor-Induced Changes in Ca2+ Influx, K+ Efflux, and 4-Hydroxybenzoic Acid Synthesis in Protoplasts of Daucus carota L

1993

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Section: Discussionmentioning

confidence: 99%

Elicitor-Induced Changes in Ca2+ Influx, K+ Efflux, and 4-Hydroxybenzoic Acid Synthesis in Protoplasts of Daucus carota L

1993

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“…This procedure also removed some neutral sugars but did not significantly reduce the size or activity of the polysaccharide. .Endopolygalacturonase purified from the fungus R. stolonifer (4) was a gift of Charles West.…”

Section: Methodsmentioning

confidence: 99%

Proteinase inhibitor-inducing factor activity in tomato leaves resides in oligosaccharides enzymically released from cell walls

Bishop

Makus

Pearce

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

172

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The synthesis andaccumulation of proteinase inhibitor I in excised tomato leaves can be induced with oligosaccharides obtained by fungal endo-a-1,4-polygalacturonase digestion of a pectic polysaccharide (Mr 5000-10,000) isolated from tomato leaves. Active oligosaccharides were-also released from isolated tomato leaf cell walls by endopolygalacturonases partially purified from tomato plants. It.is suggested that oligosaccharides, released from plant cell wall pectic polysaccharides by either endogenous or exogenous endopolygalacturonases at a wound or infection site, may have hormone-like roles in regulating plant defense responses in unwounded tissues many centimeters away from the site of release.Severe wounding of tomato or potato leaves by attacking pests or other mechanical damage releases a putative wound hormone that is transported throughout the plants where it induces leaves to initiate synthesis and accumulation of two proteinaceous inhibitors of serine endopeptidases (1). This proteinase inhibitorinducing factor (PIIF) has been consistently associated with polysaccharides ofwidely varying sizes (2), suggesting that PIIF activity may be intrinsic to a specific saccharide sequence or structure.Recently, a highly active tomato PIIF fraction of Mr 5000-10,000 was shown to be pectic polysaccharide. It has a composition similar to that of an enzymically produced fragment of sycamore cell walls, of Mr 200,000, that was shown to have activity similar to that oftomato PIIF (3). This evidence suggested that PIIF activity may be associated with a structural component of plant cell walls. However, in view.of the large sizes of.both the tomato pectic polysaccharide and the sycamore cell wall fragment, it is questionable whether they would be rapidly transported through the plant vascular system after wounding in vivo.-In this communication we report that an endopolygalacturonase purified from.the fungus Rhizopus stolonifer (4) degrades tomato PIIF into oligosaccharides that are active inducers of proteinase inhibitor I when supplied to excised tomato leaves. We also show that a mixture of two endopolygalacturonases, partially purified from. tomato fruit, degrades both tomato PIIF and purified tomato cell walls into PIIF-active oligosaccharides. These results suggest that PIIF activity produced in vivo by cell damage resides in small hydrolytic fragment(s) of plant cell walls. MATERIALS AND METHODSTomato PIIF is a partially purified, highly methylated soluble pectic polysaccharide of Mr 5000-10,000 on the basis of its elution profile from Sephadex G-50 when compared to protein standards (unpublished data). Acid-demethylated tomato PIIF polysaccharide was prepared by dissolving 50 mg oftomato PIIF in 5 ml of 2 M trifluoroacetic acid and heating under reduced pressure at 859C for 1 hr. The reaction mixture was chilled in an ice bath and then centrifuged at 25,000 X g for 10 min. The supernatant was lyophilized to remove the trifluoroacetic acid. The residue was dissolved in water, adsorbed on DE-52 (Whatman),...

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“…Among the strains tested, the best 3 PG producers (All, LKN, and UQM 186F) were selected from the pool of Rhizopus strains as first selection step and with IFO 5441 (referred strain) they were subjected to subsequent optimization tests. The PG activities of the selected strains are in the range of 3.3-4.3 U/ml (1.5-2.0 U/mg protein) which are greater than that of reported value of the PG activity of Rhizopus arrhizus (0.336 U/mg protein) obtained from rotted apricot (11) and Rhizopus stolonifer (1.2 U/ml) grown in synthetic glucoseasparagine medium (9); quite comparable to that of Aspergillus niger (1.76 U/mg protein) cultured in a liquid medium containing satsuma mandarin peel (5); but less than that of the reported value of R. oryzae (70 U/ml or 29 U/g substrate) grown in orange finisher pulp (7) pH and temperature optima Figure 1 (a, All; b, UQM 186F; c, LKN; d, IFO 5441) shows pH optima of 4 enzyme solutions. The enzyme solutions 'were then subjected to reaction temperatures at their respective optimum pHs.…”

Section: And Discussionmentioning

confidence: 68%

“…On the basis of PG activity assay, pH optimum of PG was determined at indicated pH by using various buffer pH, i.e., 0.1 M glycine buffer (glycine-HCI, pH 2-3), acetate buffer (pH 3.5-5.5), 0.1 M phosphate buffer (pH 6-8) and 0.1 M sodium carbonate buffer (Na2CO3-NaHCO3, pH [8][9][10][11]. Temperature optimum of PG activity was determined at the range from 20 to 70°C at the optimum pH of the respective enzyme solution.…”

Section: Methodsmentioning

confidence: 99%

Polygalacturonase production by Rhizopus spp.

Elegado¹,

Fujio²

1993

J. Gen. Appl. Microbiol.

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Two good polygalacturonase (PG) producing strains were selected from 21 Rhizopus spp. isolates from `ragi' and fermented foods and from 4 authentic Rhizopus strains. Strain LKN produced 3.2 U/mg protein of crude enzyme extract (0.68 U/g substrate) in 3 days solid culture of pectin and cassava starch supplemented wheat bran. Strain Al 1-enzyme showed a wide pH stability range of pH 2-11 and tolerance at 50°C for 20 min.Pectic enzymes from plant and microbial sources have been studied intensively in the past and they are broadly classified into pectinesterase (PE), which saponifies the esterified portions of the pectin chain, and depolymerases which are responsible for cleaving the chain (17). Among the depolymerases, the major one in terms of hydrolytic function is the endo-polygalacturonase (PG, EC 3.2.1.15). Several review articles that covered the Pectic enzymes secreted by various plants and microorganisms, generally reported that plants contain high PE activities. On the other hand, PG is said to be the major pectic enzymes of molds and yeast while bacteria possess higher activities for PE and the lyases (2,4,18, 23, 25) . But molds seemingly prove to be more useful because of higher pectic enzyme production and optimum activity at a lower pH range suited for the most common industrial use, i.e. juice clarification (3). Hence, a lot of efforts have been devoted to the study of the pectic enzymes by molds. In the case of researches on the pectolytic activity of Rhizopus spp., most are related to fruit and vegetable degradation (1). A recent study used citrus waste as substrate for PG production by Rhizopus oryzae (7). But in general, it seems that less attention is being paid regarding the utilization of waste substrate material for the culture and screening of Rhizopus strains for PG production.In this study, most of the Rhizopus strains used were isolated from `ragi,' a rice wine inoculum, and some fermented foods, such as `tempeh' that are native to

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Polygalacturonase from Rhizopus stolonifer, an Elicitor of Casbene Synthetase Activity in Castor Bean (Ricinus communis L.) Seedlings

Cited by 115 publications

References 22 publications

Elicitor-Induced Changes in Ca2+ Influx, K+ Efflux, and 4-Hydroxybenzoic Acid Synthesis in Protoplasts of Daucus carota L

Elicitor-Induced Changes in Ca2+ Influx, K+ Efflux, and 4-Hydroxybenzoic Acid Synthesis in Protoplasts of Daucus carota L

Proteinase inhibitor-inducing factor activity in tomato leaves resides in oligosaccharides enzymically released from cell walls

Polygalacturonase production by Rhizopus spp.

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