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Abstract

The purpose of this work was to investigate whether ethylene is involved in the oxidative and defensive responses of barley to the aphids Schizaphis graminum (biotype C) and Rhopalophum padi. The effect of aphid infestation on ethylene production was measured in two barley cultivars (Frontera and Aramir) that differ in their susceptibility to aphids. Ethylene evolution was higher in plants infested for 16 hr than in plants infested for 4 hr in both cultivars. Under aphid infestation, the production of ethylene was higher in cv. Frontera than in Aramir, the more aphid susceptible cultivar. Ethylene production also increases with the degree of infestation. Maximum ethylene evolution was detected after 16 hr when plants were infested with 10 or more aphids. Comparing the two species of aphids, Schizaphis graminum induced more ethylene evolution than Rhopalosiphum padi. Infestation with S. graminum increased hydrogen peroxide content and total soluble peroxidase activity in cv. Frontera, with a maximum level of H2O2 observed after 20 min of infestation and the maximum in soluble peroxidase activity after 30 min of infestation. When noninfested barley seedlings from cv. Frontera were exposed to ethylene, an increase in hydrogen peroxide and in total peroxidase activity was detected at levels similar to those of infested plants from cv. Frontera. When noninfested plants were treated with 40 ppm of ethylene, the maximum levels of H2O2 and soluble peroxidase activity were at 10 and 40 min, respectively. Ethylene also increased the activity of both cell-wall-bound peroxidases types (ionically and covalently bound), comparable with infestation. These results suggest that ethylene is involved in the oxidative responses of barley plants induced by infestation.

Effects of Shade Treatments on Photosynthetic Characteristics, Chloroplast Ultrastructure, and Physiology of Anoectochilus roxburghii

“…Crude enzyme preparation for superoxide dismutase (SOD) and peroxidase (POD) assays involved tissue homogenization in 5 ml of 100 mM potassium phosphate buffer (pH 7.0) following the procedure of He et al [36]. Assays used for POD, SOD, and catalase (CAT) were those described by Argandona et al [37] and Yin et al [38]. Soluble sugar (SS) content was determined using anthrone colorimetry as described by Li [39], and malondialdehyde (MDA) content was measured by the thiobarbituric acid method according to Deng et al [40].…”

Mechanisms of plant defense against insect herbivores

“…35,141 Induction of H 2 O 2 has been studied in oat, wheat, barley and groundnut against D. noxia, R. padi, Schizaphis graminum Rond., H. armigera and S. litura. 4,5,132,139 Argandona et al 144 observed induction of H 2 O 2 in barley infested with S. graminum after 20 min of infestation, indicating that H 2 O 2 could be the beginning of a cascade of physiological and molecular events leading to production of further defensive components, and protection of plants from subsequent damage. ROS mediate the defensive gene activation and establish additional defenses by regulating the transcription and/or by interacting with other signal components like phosphorylation in plant systems in response to a variety of stresses.…”

Arabidopsis thaliana—Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

“…For example, increases in ethylene production was observed in tomato infested with potato aphid, alfalfa infested with Therioaphis maculate (spotted alfalfa aphid), wheat infested with Schizaphis graminum (greenbug), and barley infested with Rhopalosiphum padi (oat aphid) and Russian wheat aphid (Dillwith et al, 1991; Anderson and Peters, 1994; Miller et al, 1994; Argandoña et al, 2001; Mantelin et al, 2009). Changes in expression of genes putatively involved in ethylene metabolism/signaling also have been observed in melon plants responding to the melon and cotton aphid infestation, in tomato infested with the potato aphid, and Arabidopsis infested with the GPA (Moran et al, 2002; Anstead et al, 2010; Mantelin et al, 2009).…”