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De novo biosynthesis of defense root exudates in response to Fusarium attack in barley
Author(s) -
Lanoue Arnaud,
Burlat Vincent,
Henkes Gunnar J.,
Koch Imke,
Schurr Ulrich,
Röse Ursula S. R.
Publication year - 2010
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2009.03066.x
Subject(s) - rhizosphere , biology , fusarium , botany , exudate , hordeum vulgare , cinnamic acid , biosynthesis , secondary metabolism , ferulic acid , plant defense against herbivory , vanillic acid , microbiology and biotechnology , bacteria , biochemistry , poaceae , food science , gene , genetics
Summary• Despite recent advances in elucidation of natural products in root exudates, there are significant gaps in our understanding of the ecological significance of products in the rhizosphere. • Here, we investigated the potential of barley ( Hordeum vulgare ) to secrete defense root exudates when challenged by the soilborne pathogen Fusarium graminearum . • Liquid chromatography with photodiode array detection (LC‐DAD) was used to profile induced small‐molecular‐weight exudates. Thus, t ‐cinnamic, p ‐coumaric, ferulic, syringic and vanillic acids were assigned to plant metabolism and were induced within 2 d after Fusarium inoculation. Biological tests demonstrated the ability of those induced root exudates to inhibit the germination of F. graminearum macroconidia. In vivo labeling experiments with 13 CO 2 revealed that the secreted t ‐cinnamic acid was synthesized de novo within 2 d of fungal infection. Simultaneously to its root exudation, t ‐cinnamic acid was accumulated in the roots. Microscopic analysis showed that nonlignin cell wall phenolics were induced not only in necrosed zones but in all root tissues. • Results suggest that barley plants under attack respond by de novo biosynthesis and secretion of compounds with antimicrobial functions that may mediate natural disease resistance.