engleski

Quercetin induces defense response in cucumber mosaic virus infected plants

A remarkable spectrum of biochemical activities of quercetin, a prominent flavonoid, and its implications on human health as well as its role in normal growth and development of plants has been extensively studied. In this study, influence of quercetin on cucumber mosaic virus (CMV) associated with satellite RNA and involvement of quercetin in defense response of CMV-infected Nicotiana megalosiphon plants were investigated. The pathogens' replicative RNA. The viral electrophoretic pattern and the satellite band were significantly stronger after simultaneous inoculation of CMV and quercetin in host plants compared to plants infected without quercetin. Infected plants, sprinkled daily with quercetin have shown significant increase in leaf mass, as well as lower quantity of pathogens' replicative RNA, compared to quercetin untreated plants. These results suggest that antiphytoviral activity of quercetin is time- and concentration-dependent. Fluorescence methods were used to characterize interactions between quercetin and virus nucleoprotein, as well as quercetin and isolated ssRNA. Results revealed inability of quercetin to bind to virus nucleoprotein or isolated ssRNA suggesting that its antiphytoviral activity is not due to the direct virus inactivation. Examination of glycoproteins reacting with a lectine ConA revealed different protein patterns of quercetin-treated and untreated CMV-infected plants compared to healthy control. Healthy and quercetin-treated infected plants have shown significantly lower expression of about 38 kDa glycoprotein in comparison with quercetin untreated infected plants. This suggests its possible role in pathogens' replication mechanism. On the contrary, glycoproteins of about 22 and 29 kDa were absent in healthy plants and more extensively expressed in quercetin-treated compared to untreated infected plants, indicating their involvement in defense response of infected plants. Heat shock protein HSP70 was equally expressed in quercetin-treated und untreated samples.

cucumber mosaic virus; Nicotiana megalosiphon

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