Biomedical Engineering Reference
In-Depth Information
Since the localized measurement of jasmonic acid has not been conducted
yet, the expression of genes responsible for jasmonic acid production may
be a good indicator of produced jasmonic acid, for plants such as
H. vulgare
and
M. trancatula
(Maucher et al. 2000, Hause et al. 2002, Stenzel et al. 2003,
Isayenkov et al. 2005).
In addition, the production of a protein, produced by the expression of
the related genes can also indicate the increased levels of jasmonic acid with
signaling capacity (Hause et al. 1996). The related proteins are produced
in plant cells with arbuscules, while in the cortex cells of non-mycorrhizal
plants the related protein was not detectable (Hause et al. 2002, Isayenkov
et al. 2005).
The reason for increased level of jasmonic acid in mycorrhizal
H. vulgare
has been attributed to the osmotic stress resulted by the increased level
of carbohydrates, transferred from the shoots to the roots of mycorrhizal
plants. This is because the nutritional demanding of mycorrhizal roots, as
a sink, increases compared with non-mycorrhizal roots (Hause et al. 2007).
The increased movement of carbohydrates from the shoots of
mycorrhizal plants to the roots (Alkan et al. 2006, Nakano-Hylander and
Olsson 2007, Miransari et al. 2007, 2008, Miransari 2010a, b) and expression
of the related genes may indicate these strategies: (1) source tissues provide
carbohydrates, which are transferred to the roots (sink tissues) increasing
osmotic stress, (2) the carbohydrates may be able to induce the expression
of genes, which are responsible for the production of enzymes producing
jasmonic acid, (3) the produced jasmonic acid, which can also affect the
production of arbuscules in mycorrhizal roots, can also enhance their sink
capacity (Hause et al. 2007, Hause and Schaarschmidt 2009).
At the time of symbiosis, jasmonates may have the following effects on the
signaling pathways: (1) increase the production of phenylalanine ammonia
lyase mRNA and the activity of PAL (which does not directly regulate the
fl avonid pathway and catalyses phenylalanine to hydroxycinnamic acid
and the deamination of phenylalanine to cinnamic acid) enzyme (Thoma
et al. 2003). In
M. truncatula
the transcripts are responsible for:
1) The production of enzymes related to the biosynthesis of isofl avonoid
pathways, including PAL and CHS (another enzyme regulating
the fl avonoid pathway), particularly in the cells with arbuscules
(Harrison and Dixon 1994).
2) Reshape the cellular structure, including the rearrangement of
microtubules in the cells with arbuscules and in the cells, which are
not inoculated (Bonfante, et al. 1996, Gomez et al. 2009). In addition,
the produced
B
-tubulin gene, which is necessary for the production
of cellular microtubules is expressed in mycorrhizal roots (Manthey
