Biomedical Engineering Reference
In-Depth Information
C
HAPTER
12
Signaling Molecules in the
Arbuscular Mycorrhizal Fungi
Mohammad Miransari*
Abstract
Arbuscular mycorrhizal (AM) fungi are non-specifi c symbionts developing
mutual and benefi cial symbiosis with most of terrestrial plants. Because of the
obligatory nature of the symbiosis the presence of the host plant for the onset and
proceeding of symbiosis is necessary though the fungi spores are able to germi-
nate in the absence of the host plant. The fungi detect the presence of the host
plant through some signal communications. Among the signal molecules, which
can affect mycorrhizal symbiosis are plant hormones, which may positively or
adversely affect the symbiosis. In this article some of the most recent fi ndings
regarding the effects of different signal molecules, which also include plant hor-
mones, on the process of AM symbiosis are reviewed. The ecological signifi cance
of the AM symbiosis and how it may be affected is also presented. Elucidation
of the processes involved in the symbiosis of the host plant with AM fungi with
emphasis on the related signaling processes can help to the development of ideas
regarding the enhanced symbiosis effi ciency. This can be of agricultural and
ecological signifi cance.
INTRODUCTION
The most abundant fungi in agricultural soils are arbuscular mycorrhizal
(AM, phylum Glomeromycota) fungi accounting for 5 to 50% of microbial
biomass (Cardoso and Kuyper 2006). AM fungi are soil fungi developing
symbioses with most crop plants and hence, are of biological and
ecological signifi cance. The fungi obtain exchangeable soluble carbon by
carbohydrates from the host plant and greatly enhance plant capacity to
