Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.jplph.2005.01.014
Title (Primary) Auxins in the development of an arbuscular mycorrhizal symbiosis in maize
Author Fitze, D.; Wiepning, A.; Kaldorf, M.; Ludwig-Müller, J.
Source Titel Journal of Plant Physiology
Year 2005
Department BOOEK
Volume 162
Issue 11
Page From 1210
Page To 1219
Language englisch
Keywords Glomus intraradices; Zea mays; Arbuscular mycorrhiza; Auxin conjugates; Indole-3-acetic acid; Indole-3-butyric acid; Trifluoro-IBA
Abstract While the levels of free auxins in maize (Zea mays L.) roots during arbuscular mycorrhiza formation have been previously described in detail, conjugates of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) with amino acids and sugars were neglected. In this study, we have therefore determined free, ester and amide bound auxins in roots of maize inoculated with Glomus intraradices during early stages of the colonization process. Ester conjugates of IAA and IBA were found only in low amounts and they did not increase in AM colonized roots. The levels of IAA and IBA amide conjugates increased 20 and 30 days past inoculation (dpi). The formation of free and conjugated IBA but not IAA was systemically induced during AM colonization in leaves of maize plants. This implicated a role for auxin conjugate synthesis and hydrolysis during AM. We have therefore investigated the in vivo metabolism of 3H-labeled IBA by TLC but only slight differences between control and AM-inoculated roots were observed. The activity of auxin conjugate hydrolase activity measured with three different putative substrates showed a decrease in infected roots compared to controls. The fluorinated IBA analog TFIBA inhibited IBA formation in leaves after application to the root system, but was not transported from roots to shoots. AM hyphae were also not able to transport TFIBA. Our results indicate complex control mechanisms to regulate the levels of free and conjugated auxins, which are locally and systemically induced during early stages of the formation of an arbuscular mycorrhizal symbiosis.
Persistent UFZ Identifier
Fitze, D., Wiepning, A., Kaldorf, M., Ludwig-Müller, J. (2005):
Auxins in the development of an arbuscular mycorrhizal symbiosis in maize
J. Plant Physiol. 162 (11), 1210 - 1219 10.1016/j.jplph.2005.01.014