Changes in Antioxidative Compounds and Enzymes in Small-Leaved Linden (Tilia cordata Mill.) in Response to Mistletoe (Viscum album L.) Infestation

Abstract

Mistletoe infestation leads to a decrease in the growth of woody plants, their longevity, and partial or complete drying of the top, as well as premature death. Various environmental stress factors, both abiotic and biotic, stimulate the formation of reactive oxygen species and the development of oxidative stress in plant tissues. This study aimed to investigate the effect of mistletoe (Viscum album L.) infestation on the response of the antioxidative defense system in leaves of small-leaved linden (Tilia cordata Mill.). Leaves from infested trees were taken from branches (i) without mistletoe, (ii) with 1–2 mistletoe bushes (low degree of infestation), and (iii) with 5–7 mistletoe bushes (high degree of infestation). The relative water content and the chlorophyll a and b contents in leaves from linden branches affected by mistletoe were significantly lower than those in leaves from non-infested trees and from host-tree branches with no mistletoe. At the same time, leaves from branches with low and high degrees of infestation had significantly higher electrolyte leakage, malondialdehyde and hydrogen peroxide content, oxidized forms of ascorbic acid (dehydroascorbic and 2,3-diketogulonic acids), and oxidized glutathione. The results of principal component analysis show that the development of oxidative stress was accompanied by an increase in proline content and in superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, and glutathione reductase activity. Several biochemical parameters (proline, ascorbic acid, dehydroascorbic acid, glutathione, glutathione peroxidase, ascorbate peroxidase, and dehydroascorbate reductase) were found to be altered in leaves from host-tree branches with no mistletoe. This result indicates that the mistletoe infestation of trees not only causes local changes in the locations of hemiparasite attachment, but also affects the redox metabolism in leaves from other parts of the infested tree.

The Anti-Inflammatory Activity of Viscum album

“…The relationship between mistletoe and its host, besides behaviour, primary metabolism and ecology, deeply affects the secondary metabolism as well [ 25 , 26 ]. Many studies evidenced a relevant interchange and influx of material and information between the metabolisms of the parasite and the host [ 27 , 28 , 29 , 30 ], as evidenced also by the characteristics of the haustorial system and the parasitism of selected aerial parts of the host [ 31 ]. As in other investigated cases of parasitism, the conclusion is that in these cases, parasite and host partly compart metabolism, giving rise to a fused complex dynamic system, such as those named superorganisms.…”

The Antioxidant Activity of Mistletoes (Viscum album and Other Species)

“…In this scenario, the antioxidant activity plays a central role, together with the anti-inflammatory properties [ 39 , 40 , 41 , 42 ]. The most reported active constituents are known flavonoids, which are present in alcoholic and aqueous extracts [ 43 , 44 ] and are already reported for their anti-ROS and radical-scavengers properties [ 45 ], with attention to the variation of the phenolic content in relation to the host [ 46 , 47 ] and the investigated subspecies [ 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. Several studies amplified the research to other constituents to evidence how they may cooperate with the activity.…”