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

Liubov Skrypnik,Pavel Maslennikov,Pavel Feduraev,Nikolay Belov,Artem Pungin

doi:10.3390/plants10091871

Liubov Skrypnik, Pavel Maslennikov + Show 3 more

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https://doi.org/10.3390/plants10091871

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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.

Highlights

European mistletoe (Viscum album L.) is a spherical hemiparasitic evergreen bush that develops stable haustoria in the host tree
This study aimed to investigate the effect of mistletoe infestation on (i) the relative water and chlorophyll content in linden leaves; (ii) the parameters of oxidative stress; (iii) the contents of non-enzymatic antioxidants; and (iv) the activity of antioxidative enzymes (SOD, CAT, POD, as well as enzymes of the ascorbate–glutathione cycle)
One of the most important consequences of mistletoe infestation of trees is the occurrence of water scarcity, which is especially exacerbated in arid regions and/or dry years [3,27]

Summary

Introduction

European mistletoe (Viscum album L.) is a spherical hemiparasitic evergreen bush that develops stable haustoria in the host tree. The geographic distribution of mistletoe is limited primarily by temperature. The low average temperatures of the coldest and warmest months of the year limit the distribution of European mistletoe [1]. The warmer the climate is, the wider the range mistletoe will have, increasing the area of infested trees [1]. Mistletoe infestation causes a decrease in the growth of trees and their longevity, and partial or complete drying of the treetop, as well as premature death [2,3]. Mistletoe is believed to capture water, mineral nutrients, and carbohydrates (glucose, fructose, sucrose) from their host trees, thereby disrupting the osmotic and carbon balance of the host [4,5]

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