Cell Wall and Protoplast Isoperoxidases of Corn Leaves in Relation to Cut Injury and Infection with Helminthosporium maydis

Abstract

The nature of the involvement of peroxidases in plant resistance to fungal, bacterial, and viral diseases has been extensively investigated (7,13,18,22,28,30). However, the emphasis has been on soluble peroxidases, separated from tissue homogenates by centrifugation, and the cell wall-bound components have usually been disregarded. Since parasitic microorganisms are in intimate association with host cell walls at entry, at the establishment of the host-parasite relationship, and during spread in the host tissues, cell wall peroxidase fractions may be specifically involved in the plant-response to the parasite.In previously reported research on tobacco pith and sweet potato root parenchyma (5), significant differences were found between cell wall and protoplast peroxidases in their isoenzyme patterns, activity, and reaction to mechanical injury. It has been University, Columbus, Ohio 43210shown recently that the reaction of tobacco leaf peroxidase to cutting injury did not differ from that to tobacco mosaic virus infection in respect to the qualitative isoperoxidase patterns in the protoplast and cell wall-free or ionically and covalently bound fractions (4).This report deals with the reaction of corn leaf peroxidase to cutting injury and to infection with the fungus Helminthosporium maydis. Funk inbred lines with normal and Texas male-sterile cytoplasm were used. In a previous investigation (10), the Tms' cytoplasm inbred showed greater susceptibility to the fungus than did the N cytoplasm inbred; this was also reflected in a greater electrolyte and peroxidase leakage from the infected leaves. MATERIALS AND METHODSThe plants were grown in vermiculite on a 4-fold diluted Hoagland's solution in a growth chamber at 28 C and 16-hr daily photoperiod (1200 ft-c). At the four leaf stage, the laminae of the second and third leaves were detached and immediately weighed, stapled to a sheet of Whatman No. 3 filter paper, and cut into 8-mm segments or sprayed with a H. maydis race T spore suspension (20,000-30,000/ml) in H,O containing 0.1 % Tween 40. The suspension was prepared from cultures incubated on a glucose-L-asparagine agar medium for 12 to 14 days at 28 C. Intact (control) and cut laminae were sprayed with water containing 0.1% Tween 40. Six laminae from three plants were used in each of three replications per treatment. The laminae were incubated in the dark in a water vaporsaturated atmosphere for 16 and 40 hr. At the end of incubation, the infected laminae of the N and Tms cytoplasm inbreds had oblong lesions 1 to 2 and 3 to 4 mm long, respectively. The Tms inbred showed also slight chlorosis and some flaccidity.Immediately after sampling, the tissue was frozen and kept in a deep freeze. Unfortunately, attempts to isolate free peroxidase from cell walls before freezing by vacuum-infiltration, followed by centrifugation, were not successful. Therefore, the protoplast peroxidase fraction was separated together with the free fraction in the cell wall.Procedures related to peroxidase isolation were similar ...

Cell Wall and Protoplast Isoperoxidases in Tobacco Plants in Relation to Mechanical Injury and Infection with Tobacco Mosaic Virus

“…This report mainly deals with age-and injury-related changes in cell peroxidase in tobacco leaves and with the possible involvement of this enzyme in the tissue response to TMV infection, in particular in Samsun NN tobacco plants. Con-currently, a study has been undertaken on cell peroxidase changes, induced by cutting injury and infection with Helininthosporium maydis in leaves of two corn inbreds differing from each other in their susceptibility to the fungus (5).…”

Soluble and Cell Wall Peroxidases in Reed Canarygrass in Relation to Disease Resistance and Localized Lignin Formation

“…The assay for peroxidase was that described by Jennings et al (6). Polyacrylamide disc gel electrophoresis as described by Davis (4) (2). In Japanese radish (Raphanus sativus), a cathodic isozyme has been suggested as being the primary isozyme involved in regulation of lignin formation in response to disease (10).…”

Molecular diversity and plant disease resistance: An electrophoretic comparison of near-isogenic lines of wilt-resistant or -susceptible Pisum sativum L. cv. William Massey

“…We have therefore examined some enzymes of the uninfected pea lines. Peroxidase is frequently implicated in the disease resistance response (HADwIGER & SCHWOCHAU, 1969;SAKO & STAHMAN, 1972;URITANI, 1963;RETIG, 1974;BIRECKA et al, 1975). The changes produced are induced by the pathogen attack and are probably only a secondary effect of the plant's response (JOHNSON & LEE, 1978;NADOLNY & SEQUEIRA, 1980).…”