Mistletoe infestation mediates alteration of the phytohormone profile and anti-oxidative metabolism in bark and wood of its host Pinus sylvestris.
European mistletoe (Viscum album L.) has largely infested Central European forests and causes high mortality probability particularly in dry years. However, little information is available about the consequences of mistletoe infestation for metabolic processes in bark and wood of its host, despite their important roles in infestation defense. We analyzed the tissue hydration, carbohydrate composition, phytohormone profile, reactive oxygen species and anti-oxidant levels in bark and wood of Scots pines (Pinus sylvestris L.), as dependent on mistletoe infestation. As a consequence of mistletoe infestation, host bark and wood showed impaired hydration and reduced total carbon content. In the bark, soluble sugar and lignin contents increased, apparently at the expense of holo-cellulose. Hydrogen peroxide accumulation was accompanied by increased glutathione and decreased reduced ascorbic acid levels. Mistletoe infestation mediated alteration of the phytohormone profile in bark and wood of its host. Cytokinins, jasmonic acid and abscisic acid levels increased in both tissues, whereas salicylic acid and indole-3-acetic acid, which were only detected in the bark, declined. The present results show that mistletoe infestation affects both the host's anti-oxidative defense system and the phytohormone profile after establishment of the xylem tapping haustorium. The significance of these processes for the development of the woody mistletoe stem and the haustorium is discussed.
College of Forestry, Northwest A&F University, 3 Taicheng Road, 712100 Yangling, China.|Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 53/54, 79110 Freiburg, Germany.
Bin
B
Hu
RIKEN Center for Sustainable Resource Science, Tsurumi, 230-0045 Yokohama, Japan.
Hitoshi
H
Sakakibara
RIKEN Center for Sustainable Resource Science, Tsurumi, 230-0045 Yokohama, Japan.
Yumiko
Y
Takebayashi
Department of Forest Protection, FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Wonnhaldestr. 4, 79100 Freiburg, Germany.
Franziska S
FS
Peters
Department of Forest Protection, FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Wonnhaldestr. 4, 79100 Freiburg, Germany.
Jörg
J
Schumacher
Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 53/54, 79110 Freiburg, Germany.
Monika
M
Eiblmeier
Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 53/54, 79110 Freiburg, Germany.
Leila
L
Arab
Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 53/54, 79110 Freiburg, Germany.
Jürgen
J
Kreuzwieser
Forest Botany and Tree Physiology, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
Andrea
A
Polle
Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg, Georges-Koehler-Allee 53/54, 79110 Freiburg, Germany.|College of Sciences, King Saud University, 11451 Riyadh, Saudi Arabia.
Heinz
H
Rennenberg
D000975:Antioxidants / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry; D041605:Pinus sylvestris / Q000469:parasitology / Q000502:physiology*; D024301:Plant Bark / Q000737:chemistry*; D010937:Plant Growth Regulators / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry; D028182:Viscum album; D014934:Wood / Q000737:chemistry*
D000975:Antioxidants; D002241:Carbohydrates; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species
ROS; ascorbate; glutathione; mistletoe parasitism; phytohormone profile; pine trees