Host--Pathogen Interactions. Iii. Proteins From Plant Cell Walls Inhibit Enzymes Secreted by Plant Pathogens.

Albersheim, Peter; Anderson, Angelika

doi:10.2172/4753420

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…Under this heading, there is also the recent work on glycoproteins, similar to phytoagglutinins, from cell walls of a number of plant species which are very effective and specific inhibitors of pectic enzymes im portant in wall degradation. Plants may contain more than one of these proteins, which also inhibit enzymes from some sources more than from others (Albersheim & Anderson 1971). W hether they are specific enough in this respect to have other than a general role in resistance remains to be seen.…”

Section: Resistance To Colonization and The Role Of The Cell Wallmentioning

confidence: 99%

Introduction: disease resistance in plants

Wood

1972

Proc. R. Soc. Lond. B.

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This paper discusses in general terms the mechanisms proposed to explain the resistance of higher plants to infection and colonization by bacteria and fungi, especially the type of resistance associated with rapid killing of host cells and very limited growth of the pathogen; that is, with the hypersensitive reaction of the plant to infection (h.r.). The main points considered are: the significance of the h.r. for obligate and other types of parasites; the nature of the h.r. and the means by which it is invoked; the absence of the h.r in compatible host-parasite combinations; the h.r. and the production of phytoalexins, and the role of the latter in resistance; the part played by cell-wall degrading enzymes in the earliest stages of infection; the relation between the h.r. in interactions between races of a pathogen and different forms of a host species, on the one hand, and the resistance of all plants to almost all pathogens, on the other. Also discussed is the less specific but important type of resistance in which the pathogen continues to grow in resistant plants more slowly than in susceptible plants.

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Section: Resistance To Colonization and The Role Of The Cell Wallmentioning

confidence: 99%

Introduction: disease resistance in plants

Wood

1972

Proc. R. Soc. Lond. B.

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“…This endopolygalacturonase is the only enzyme, of several polysaccharidedegrading enzymes studied, which could initiate degradation of isolated cell walls. Therefore, it was of considerable interest to find that a variety of dicotyledonous plants contain proteins, associated with their cell walls, that are able to inactivate the endopolygalacturonases that are among the first degradative enzymes secreted by the fungal pathogens during culture (3). Just (6,16), bacterial (11,15), and fungal infections of plant tissues (21).…”

mentioning

confidence: 99%

“…In order to determine whether C. lindemuthianum produces inhibitors of the /3-1 ,3-endoglucanase and of the chitinase, we partially purified these enzymes following the procedures described by Abeles et al (1) C. lindemnuthianum was grown in shake cultures as described previously (9) 3-glucanase inhibitor activity is detectable in the potassium acetate extract of the alcohol-precipitated extracellular media, the amount of inhibitor activity is increased approximately 10-fold by heating the preparation at 93 C for 10 min. The amount of endoglucanase inhibitor present in the extracellular culture filtrate is variable but, in several experiments, 1 ml of the heated culture filtrate had at least enough inhibitor to inactivate completely the endoglucanase present in our standard assay.…”

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Host-Pathogen Interactions

Albersheim¹,

Valent²

1974

Plant Physiol.

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The results presented demonstrate that microbial pathogens of plants have the ability to secrete proteins which effectively inhibit an enzyme synthesized by the host; an enzyme whose substrate is a constituent of the cell wall of the pathogen. The system in which this was discovered is the anthracnose-causing fungal pathogen (Colletotrichum lindemuthianum) and its host, the French bean (Phaseolus vulgaris). An endo-3-1 , 3-glucanase present in the bean leaves is specifically inhibited by a protein secreted by C. lindentuthianum. The cell walls of C. lindemnuthianum are shown to be composed largely of a 1,3-glucan. METHODS AND RESULTS Since the composition and structure of the cell walls of Colletotrichum lindemuthianum had not previously been reported, we undertook to isolate cell walls from the mycelia of this fungus (22). The mycelia were ground in a Sorvall Omnimixer and then in a Waring Blendor in 5 volumes of 50 mm potassium phosphate, pH 7.0, at 2 C. The mycelial walls were suspended in 1 % sodium dodecyl sulfate and stirred at 93 C for 0.5 hr. The cell wall pellet was washed repeatedly with buffer, then with a mixture of chloroform-methanol (1:1), and finally with acetone before being air dried at room temperature.The sugar composition of the mycelial cell walls was determined by acid hydrolysis followed by the formation of the corresponding alditol acetates and separation of these derivatives by quantitative gas-liquid chromatography (5,12). The results of this analysis (Fig. 1) demonstrate that the carbohydrate portion of the cell walls of C. lindemuthianuin mycelia is largely glucose-containing polymers (91 %). In addition to glucose, the walls contain small amounts of galactose (5%) and mannose (4%). The chromatogram presented in Figure 1 was obtained following hydrolysis of the cell walls for 1 hr at 121 C in 2 N trifluoroacetic acid. Hydrolysis of the glucose polymers under these conditions suggests that they are not cellulose-like. Hydrolysis of the mycelial cell walls for 2 hr at 121 C in 6 N trifluoroacetic acid results in a lower yield of glucose, mannose, and galactose. The absence of glucosamine in the hydrolyzed cell wall preparation demonstrates that the walls of C. lindemuthianum do not contain chitin-like polymers.The glycosyl linkages in the cell wall polymers of C. lindeinuthianum were determined following methylation analysis and the formation of partially methylated alditol acetates by procedures previously described (8,20). The major partially methylated alditol acetate obtained in this procedure (Fig. 2

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A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

et al. 1972

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Cultures of Colletotrichum lindertmuthianum (Saccardo and Magnus) Scribner have been induced to secrete an endopolygalacturonase (polygalacturonide glyeanohydrolase EC3.2. 1.15). This enzyme has been brought to a high state of purity bv ion exchange, gel filtration, and agarose affinity chromatography. The enzyme has optimal activity at pH 5, has an apparent molecular weight as determined bv gel filtration of about 70,000, and prefers polygalacturonic acid to pectin as its substrate. The enzymne, while hydrolyzing only 1% of the glycosidic bonds, reduces the viscosity of a polygalacturonic solution by 50 %. Nevertheless, the initial as well as the final products of polygalacturonic acid hydrolysis are predominantly tri-and digalacturonic acid and, to a lesser extent, monogalacturonic acid. The purified enzyme catalyzes the removal of about 80% of the galacturonic acid residues of cell walls isolated from suspension-cultured sycamore cells (Acer pseudoplatanus) as well as from the walls isolated from 8-day-old Red Kidney bean (Phaseolus vulgaris) hypocotvls.Most polysaccharide-degrading enzymes are unable to attack effectively their substrates within isolated cell walls. Evidence has been presented which suggests that the "wall-modifying enzyme" purified from the culture filtrate of Aspergillus niger is a polygalacturonic acid-degrading enzyme (13). Treatment of walls with the wall-modifying enzyme permits other enzymes to degrade their substrates within the wall. Additional evidence that polygalacturonic acid-degrading enzymes are probably able, without assistance, to degrade cell walls comes from numerous efforts to demonstrate that these enzymes macerate plant tissues (2,4,5,7,12,18,20

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Host--Pathogen Interactions. Iii. Proteins From Plant Cell Walls Inhibit Enzymes Secreted by Plant Pathogens.

Cited by 4 publications

References 13 publications

Introduction: disease resistance in plants

Introduction: disease resistance in plants

Host-Pathogen Interactions

A Cell Wall-degrading Endopolygalacturonase Secreted by Colletotrichum lindemuthianum

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