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Jasmonates
The Jasmonates (JAs) are a group of plant hormones
which help regulate plant growth and development.
Jasmonates include jasmonic acid and its esters,
such as methyl jasmonate (Methyl Jasmonate). Like
the related prostaglandin hormones found in mammals,
the Jasmonates are cyclopentanone derivatives which
are derived biosynthetically from fatty acids. They
are biosynthesized from linolenic acid by the
octadecanoid pathway.
The level of Jasmonate in plants varies as a
function of tissue and cell type, developmental
stage, and in response to several different
environmental stimuli. High levels of Jasmonate are
also found in flowers and pericarp tissues of
developing reproductive structures and in the
chloroplasts of illuminated plants; Jasmonate levels
also increase rapidly in response to mechanical
perturbations such as tendril coiling and when
plants suffer wounding.
Demonstrated roles of Jasmonate in planta include:
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Jasmonate and Methyl Jasmonate inhibit the
germination of nondormant seeds and stimulate
the germination of dormant seeds
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High levels of Jasmonate encourage the
accumulation of storage proteins; genes encoding
vegetative storage proteins are Jasmonate
responsive and tuberonic acid (a Jasmonate
derivative) has been proposed to play a role in
the formation of tubers
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Jasmonate application can induce chlorosis and
inhibition of genes encoding proteins involved
in photosynthesis, although the purpose of this
response is unknown it is proposed that this
response to Jasmonate could help reduce the
plant's capacity for carbon assimilation under
conditions of excess light or carbon
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The role of Jasmonate accumulation in flowers
and fruit is unknown; however, it may be related
to fruit ripening (via ethylene), fruit
carotenoid composition, and expression of genes
encoding seed and vegetative storage proteins
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Jasmonate plays a role in insect and disease
resistance. Many genes during plant defense are
induced by Jasmonate; Jasmonate and ethylene may
act together in defense response
The perception of jasmonate is via the ubiquitin
system, like auxins. After the conjugation of
jasmonate and an amino acid isoleucine, it led to
the SCFCOI1 complex degrade the ubiquitin markerd
JAZ protein, and then releasing the transcription of
other transcription factors.
References:
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Creelman RA and
Mullet ME. 1997. Biosynthesis
and action of jasmonsates in
plants. Annual Review of Plant
Physiology and Plant Molecular
Biology 48: 355-381
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Falkenstein
E et al. 1991. Methyljasmonate
and α-linolenic acid are potent
inducers of tendril coiling.
Planta 185: 316– 22
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Creelman RA
etal. 1992. Jasmonic acid/methyl
jasmonate accumulate in wounded
soybean hypocotyls and modulate
wound gene expression. Proc.
Natl. Acad. Sci. USA 89:4938– 41
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Anderson JM.
1988. Jasmonic acid-dependent
increases in the level of
specific polypeptides in soybean
suspension cultures and
seedlings. Journal of Plant
Growth and Regulation. 7: 203–
11
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Pelacho AM
and Mingo-Castel AM. 1991.
Jasmonic acid induces
tuberization of potato stolons
cultured in vitro. Plant
Physiology 97: 1253– 55
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Xu Y et al.
1994. Plant defense genes are
synergistically induced by
ethylene and methyl jasmonate.
Plant Cell 6: 1077– 85
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Farmer EE
(2007). "Plant biology:
jasmonate perception machines".
Nature 448: 659–660.
doi:10.1038/448659a.
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