Association of oxidative stress components with resistance to flax powdery mildew

Abstract

Field trials were conducted in 2008/2009 and 2009/2010 growing seasons at Giza Agricultural Research Station to evaluate powdery mildew (PM) severity on nine flax cultivars. Tested cultivars could be classified into five distinct groups, i.e., highly susceptible (Corland and C.I. 2008), susceptible (Giza 7 and Marshall), moderately susceptible (Cass), moderately resistant (Dakota, Koto and Wilden) and resistant (Ottowa 770B). They showed considerable variation in PM severity ranging from 8.1 on Ottowa 770B to 97.0% infected leaves/plant on Cortland. Total soluble proteins, total phenols, peroxidase, polyphenoloxidase, ascorbic acid, tocopherol and malondialdehyde were determined in infected leaves of the tested cultivars. Pearson's correlation coefficient was calculated to measure the degree of association between PM severity and each biochemical component. All components showed significant (P<0.05) or highly significant (P<0.01) negative correlation with PM severity except MDA, which showed positive correlation (P<0.01). The results of the present study suggest that phenols and MDA in infected leaves could be used to assist the screening of resistant plants at early stages of powdery mildew development.

Antioxidant activity in safflower (Carthamus tinctorius L.) cultivars under the pathogenesis of foliar fungal disease complex

“…Table 1 clearly indicates that the maximum increase of -tocopherolwas found in varieties than hybridsthat could protects varieties more profitably than hybrids from oxidative damage caused by pathogens of foliar fungal disease complex. Similar increase of -tocopherol was found by Mohamed et al (2012) in nine flax cultivars while studying the association of oxidative stress components with resistance of flax against powdery mildew (PM) severity andspeculate that the increases in -tocopherol levels in infected leaf tissues may enhance flax resistance to PM by protecting cell membrane from oxidative damage.The result of present investigation also confirmatory with Avasthi (2014) who observed that concentration of vitamin E was increase in Aloe vera leaves infested with Colletotrichum gloeosporioides and Fusariummoniliforme fungal pathogens as compared to control leaves. Catalase (CAT) activity was declined in infected leaves of all cultivars over healthy leaves (Table 1).…”

Biochemical changes in the leaves of mungbean (Vigna radiata) plants infected by phytoplasma

“…PPO catalyzes the oxidation of phenolics to free radicals, which can react with biological molecules, thus creating an unfavorable environment for pathogen development [12,39]. PPO activity was significantly different in healthy plants of all tested genotypes and maximum PPO activity was observed in healthy plants of MH-933 ( Figure 5).…”

Biochemical Characterization of Compatible Plant Virus Interaction: A Case Study with Bunchy Top Virus-Banana Host-Pathosystem

“…The PPO catalyzes the oxidation of phenolics to free radicals that can react with biological molecules, thus creating an unfavorable environment for pathogen development (Jockusch, 1966;Mohamed et al, 2012). The PPO activity was found to increase in leaves of BBTV-infected plants of tested cultivars (Fig.…”