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Alterations in Root Exudation of Intercropped Tomato Mediated by the Arbuscular Mycorrhizal Fungus G lomus mosseae and the Soilborne Pathogen F usarium oxysporum f.sp. lycopersici
Author(s) -
HageAhmed Karin,
Moyses Anna,
Voglgruber Andreas,
Hadacek Franz,
Steinkellner Siegrid
Publication year - 2013
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12130
Subject(s) - biology , exudate , rhizosphere , chlorogenic acid , spore germination , germination , spore , glomus , fungus , botany , inoculation , root hair , horticulture , bacteria , biochemistry , genetics , gene
Arbuscular mycorrhizal fungi ( AMF ) can control soilborne diseases such as F usarium oxysporum f.sp. lycopersici ( F ol ). Root exudates play an important role in plant–microbe interactions in the rhizosphere, especially, in the initial phase of these interactions. In this work, we focus on (i) elucidating dynamics in root exudation of S olanum lycopersicum L . in an intercropping system due to AMF and/or F ol ; (ii) its effect on F ol development in vitro ; and (iii) the testing of the root exudate compounds identified in the chromatographic analyses in terms of effects on fungal growth in in vitro assays. GC ‐ MS analyses revealed an AMF ‐dependent increase in sugars and decrease in organic acids, mainly glucose and malate. In the HPLC analyses, an increase in chlorogenic acid was evident in the combined treatment of AMF and F ol , which is to our knowledge the first report about an increase in chlorogenic acid in root exudates of AM plants challenged with F ol compared with plants inoculated with AMF only, clearly indicating changes in root exudation due to AMF and F ol . Root exudates of AMF tomato plants stimulate the germination rate of F ol , whereas the co‐inoculation of AMF and F ol leads to a reduction in spore germination. In the in vitro assays, citrate and chlorogenic acid could be identified as possible candidates for the reduction in F ol germination rate in the root exudates of the AMF + F ol treatment because they proved inhibition at concentrations naturally occurring in the rhizosphere.