ROLE OF REACTIVE OXYGEN SPECIES AND ANTI-OXIDANTS IN HYPERSENSITIVE LOCAL VIRUS-INFECTED PLANTS

Ali, S.H.; Eisa, S.S.; El-Dougdoug, Kh.

doi:10.21608/jssae.2006.225031

ROLE OF REACTIVE OXYGEN SPECIES AND ANTI-OXIDANTS IN HYPERSENSITIVE LOCAL VIRUS-INFECTED PLANTS

Document Type : Original Article

Authors

¹ Dept. of Biochem Fac. Agric. Ain Shams Univ, Shoubra El-Kheima, Cairo, Egypt

² Dept. of Botany Fac. Agric. Ain Shams Univ, Shoubra El-Kheima, Cairo, Egypt

³ Dept. of Microbiology (Virology Lab.) Fac. Agric. Ain Shams Univ, Shoubra El-Kheima, Cairo, Egypt

10.21608/jssae.2006.225031

Abstract

Oxidative stress in compatible virus-host plant interactions was studied in virus-inoculated Nicotiana glut/nose plants. Leaves virus~infected plants showed highly increase in lipid peroxidation of polyunsaturated fatty acids indicating an advanced disintegration of membranes as elucidate by scanning electron microscope (SEM). A chlorotic (chlorophyll reduction) appeared 2-4 days after inoculation followed by necrotic was observed on inoculated leaves. Radical intermediates formed during lipid peroxidation co-OXidize both photosyntheSis pigments and phenolic molecules. thus it might account for virus—induced yellowing and brownish symptoms. Furthermore. in local lesion infected plants change of enzyme activities involved in the detoxification of reactive oxygen species (catalase (CAT), peroxidase (POD) and polyphenoloxidase (PPO)) was observed. After infection catalase activity was declined. while perOXidase and polyphenoloxidase activities were increased. SOS-PAGE reveals five high density proteins pattern and new proteins detected in infected leaves, may function as radical scavengers and catalyze the formation of H202. Thus it can be presumed that the enhancement of peroxidases contributes to the oxidative stress in plant and virus interactions. Moreover. infected leaves sh0wed elevation in phenol. salicylic. gallic, T—Cinnamic acid and p-hydroxy benzoic acids. besides, appearance of Kaempherol and hydroquinone as compared with healthy plants. These increases in antioxidant enzymes, phenolic compounds and high level of malonic dialdehyde (MDA) may inhibit virus infection. In addition, phenoiic compounds led to increase the ability of the plant to scavenge reactive oxygen species may hinder virus replication.