1.
Master Seminar I
Role of Jasmonic Acid in Plant
Development and Defence
Response
Shashikala
PGS17AGR7563
UNIVERSITY OF AGRICULTURAL SCIENCES, DHARWAD
College of Agriculture, Vijayapur
Department of Crop Physiology

2.
Biosynthesis of JA
Properties and Functions of JA
Introduction
Metabolic fate of JA
Role of JA in plant defence and development
Research findings
Conclusion

3.
Hormones are chemical messenger, which plays a vital role in
controlling the entire life process and other activities in the
plants -like seed germination, ripening, growth, and flowering.
The term "hormone" is derived from a Greek word meaning
“to stimulate or to enhance an activity"
Plant growth regulators are usually defined as organic
compounds other than nutrients that in smaller
concentration, affects the physiological processes of plants.
Plant hormones

4.
• The application of plant growth regulators in agriculture has
been started since 1930 in United States. Ethylene, a naturally
occurring harmone, which is the first plant growth regulator
being discovered and used successfully for enhancing the
flower production in pineapple.
• Plant growth regulators are characterized by their low rates
of application, while the high application rates of the same
compounds are often considered as herbicide
• Its toxic effects to human beings are low. Synthetic
substances that mimic such naturally occurring plant
hormones were also produced, since then the use of plant
growth regulators has been growing significantly and
becoming a major component in modern agriculture.

5.
Plant hormones

6.
 Cell elongation
 Flower
initiation
 Fruit
development
 Apical
dominance
 cell elongation + cell
division
 Delay leaf
senescence
 Reduces apical
dominance.
 Seed dormancy
 Morphogenesis.
 Bud dormancy
 Stem growth
 Flowering
Auxin (IAA) Cytokinins Gibberellins

7.
General growth inhibitor.
Causes stomatal closure.
Produced in response to stress
Inhibits the stem growth
 Fruit ripening.
 Leaf abscission
 Stem swelling
 Flower petal discoloration
Abscisic acid Ethylene

8.
INTRODUCTION
• Jasmonates are cyclo pentanone compounds
or Novel plant immune hormones which is
derived from α- linolenic acid by
the octadecanoid pathway.
• It includes group of oxygenated fatty acids
which are collectively called as oxylipins.
• Methyl jasmonate was first isolated from the
essential oil of Jasmoinum grandiflorum.
Demole et.al.,(1962).Helv.Chim.Acta.45:675-
695
• First isolated in culture filtrate of fungi
Lasiodiplodia theobromae.

9.
Jasmonic acid
• Initial discovery of metyl jasmonates (MeJA) as secondary
metabolite in essential oils of jasmine.
• Role of plant defense was first shown by Farmer and
Ryan(1990) who demonstrated the induction of proteinase
inhibitors by MeJA and JA as part of the defense respone
against herbivorous insects.
• Dgl gene is responsible of maintaining levels of JA in Zea
mays

10.
Chemical formula
C12H18O3
Molecular mass
210.27 g/mol
Density
1.1 g/cm3
Boiling point
160 °C
Properties

11.
Jasmonic acid responses (a) Chewing insects (b) Necrotropic pathogens

12.
Jasmonic acid
JA regulates -
Photosynthesis
Root and shoot growth
Seed germination
Development
Flowering
Reproduction
Senescence
JA triggers -
Defense responses

13.
Functions of jasmonic acid
Signalling molecules :-
 Plant development
 Adaptation to environmental stress
 Involved in plant defense reactions
Hormone :-
 Senescence
 Tendril coiling
 Flower development
 Leaf abscission
 Trichome induction-Tomato
 Mechanotransduction - Bryonia
 Tuberization - Potato

14.
Mechanism of signaling
The central feature of JA Signalling is the
repression of JA responses JAZ
(JASMONATE ZIM DOMAIN) protein
family.
JAZ proteins function to inhibits the activity
of transcription factors responsible for
driving the expression of JA responsive target
genes .
In the absence of JA, JAZ proteins bind to
downstream transcription factors and limit
their activity.
However, in the presence of JA or its
bioactive derivatives, JAZ proteins are
degraded, freeing transcription factors for
expression of genes needed in stress responses.

15.
Mechanism of action of JAs in biotic stress

16.
Metabolic fate of JA
Formation of amino acid conjugates by a JA conjugate
synthase (JAR1) (Staswick and Tiryaki, 2004) upon
adenylation at the carboxylic acid side-chain of JA by the
AMP-transferase activity of JAR1.
Methylation of JA by a JA-specific methyl transferase (Seo
et al.,2001).
Hydroxylation at C-11 or C-12 of the pentenyl side chain and
subsequent O-glucosylation (Sembdner and Parthier, 1993;
Swiatek et al., 2004).
Decarboxylation of JA to cis-jasmone (Koch et al., 1997).
Formation of cucurbic acids by reduction of the keto group
of the cyclo pentanone ring (Sembdner and Parthier, 1993).
Formation of jasmonoyl-1-b-glucose, jasmonoyl-1- b-
gentiobiose and hydroxyjasmonoyl-1-b-glucose(Swiatek et al.,
2004).
Conjugation of the ethylene precursor ACC to JA(Staswick
and Tiryaki, 2004).

17.
Metabolic fate of jasmonic acid. The carboxylic acid side-chain can be conjugated to the ethylene precursor
1-amino cyclopropane-1-carboxylic acid (ACC), methylated by JA methyl transferase (JMT), decarboxylated
to cis-jasmone, conjugated to amino acids such as Ile by JA amino acid synthase (Arabidopsis, JAR1;
tobacco, JAR4) or glucosylated. The pentenyl side-chain can be hydroxylated in positions C-11 or C-12. In
the case of 12-OH-JA, glucosylation or sulfation are subsequent reactions. Reduction of the keto group of the
pentenone ring can lead to cucurbic acid.

18.
The highest level of JA are reported in flowers,
reproductive tissues and young leaves.
The lower levels are found in root and mature leaves.

19.
Role of Jasmonic Acid in plant defense
and development

20.
Root Growth Inhibition
Figure 1: JA induces root growth inhibition by stimulating auxin biosynthesis via anthranilate
synthase α1(ASA1) and inhibiting the expression of genes encoding the TFs PLETHORA1 (PLT1)
and PLT2, which ensure the maintenance and activity of stem cells in the root. Root growth
inhibition by 100 mM methyl jasmonate in wild-type (Col) and the JA-insensitive mutant coi1-16
Wasternack and Hause 2013

21.
Figure 2: In tuber formation, jasmonates [JA, tuberonic acid (TA) and TA glucoside (TAG)]
might act directly after their rise following activity of LIPOXYGENASE 1 (LOX1).
Wasternack and Hause 2013.
TUBER FORMATION

22.
TRICHOME FORMATION
Wasternack and Hause 2013.

23.
Fig.4 Flower development in tomato. Flower buds, open flowers and mature fruits from
wild type and the JA-insensitive mutant jai1. Note the seedless fruits of jai1.
Wasternack and Hause 2013.
Flower Development

24.
Senescence
Wasternack and Hause 2013

25.
Research findings

26.
Jasmonic Acid Induces Tuberization of Potato Stolon
Cultured in Vitro
Tuberization in stolon cultures. A: Control without tuber formation but a good root development.
B:Tuberization under increasing JA concentrations (general absence of roots.)
Pelacho et al.(1991)

27.
Average number of tubers per stolon obtained after 30 d
in culture in a MS medium
Pelacho et al.(1991)
control
1 1.6 µM kinetin
0.5 µM JA
50 µM JA
5 µM JA
2.3
0.8
%

28.
Treatment No. of roots
per stolon
Fresh wt per
tuber(mg)
Dry wt per
tuber (mg)
Control 5.1 11.2 0.6
0.5 µM JA 1.9 26.9 2.6
5.0 µM JA 0 30.6 2.8
50 µM JA 0 16.7 1.6
11.6 µM kinetin 0 13.6 1.9
Effect of JA and Kinetin on Average Values for Number of Roots
per Stolon, and FW and DW per Tuber after 30 d in Culture
Pelacho et al.(1991)

29.
The plant growth regulator methyl jasmonate inhibits
aflatoxin production by Aspergillus flavus
• Aflatoxins are highly toxic and carcinogenic compounds
produced by the fungi Aspergillus flavus, A. parasiticus and A.
nomius.
• Aflatoxin levels in crops often rise following exposure to
certain stresses such as high temperature and drought
(Payne,1992; Sanders e t al., 1993).
• One factor influencing the production of aflatoxin is the
presence of high levels of oxidized fatty acids such as fatty
acid hydroperoxides.
• The aldehydes hexanal, trans-2-hexenal, and trans-2-
nonenal, which are hydroperoxide metabolites via
hydroperoxide lyase (Vick, 1993), generally inhibit spore
germination and aflatoxin production.
Tanrikulu et al. (1995)

30.
The plant growth regulator methyl jasmonate
inhibits aflatoxin production by Aspergillus flavus
Tanrikulu et al.(1995)

31.
Effects of jasmonates on growth and aflatoxin
production of A. flavus in vitro
MeJA-treated
untreated control
Goodrich-Tanrikulu et al.(1995)

32.
3.Effects of jasmonic acid-induced resistance in rice
on the plant brownhopper, Nilaparvata lugens
Food assimilated (A) and food ingested (B) of adult female N. lugens on rice
after activated with induced resistance by JA (2.5 mM and 5 mM) and control.
Nathan et al.(2009)

33.
Effect of induced resistance by JA on nymphal
N.lugens
Nathan et al.(2009)
A-Control,
B-2.5 mM JA,
C-5 mM JA.

34.
Effect of induced resistance by JA on egg and adult
female of N. lugens
(A-Control, B-2.5 mM JA, C-5 mM JA).
Nathan et al.(2009)

35.
Biomass production of JA
• JA is a secondary metabolite synthesized and secreted in the
late growth phase or the stationary phase after 5-10 days
fermentation.
• Botryodiplodia theobromae, mutants of Gibberella fujikuroi,
Collihya conffuens, Coprinus alkalinus and Mvcena
tintinabulum have been reported as JA producers.
• Species of the genus Botryodiplodia are able to grow in
minimum defined media.
• JA production by B.theobromae increased with sucrose and
glucose as carbon source.
• JA production by Lasiodiplodia theobromae is similar when
organic or inorganic nitrogen sources are used.

36.
Application of JA
• Jasmonic acid is also converted to a variety of derivatives
including esters such as methyl jasmonate; it may also be
conjugated to amino acids.
• According to an October 2008 BBC News report, Researchers
at the UK's Lancaster University have signed a licensing deal
with an American company (Plant Bioscience Limited) to
market jasmonic acid as a seed treatment (EU Regulation).
• The company has rolled out the technology progressively,
starting with soybean and peanut in the USA in 2010, and
product sales have increased year after year.
• Field application of JA may enhance the efficacy of parasitoids
and predators as biological control agents.

37.
• JA seed treatment stimulates the natural anti-pest
defences of the plants that germinate from the treated
seeds, without harming plant growth.
• Exogenous application of JA on rice plants elicits the
production of proteinase inhibitors, phytoalexins, PRs,
and salt-induced proteins (Tamogamia et al., 1997;
Rakwal and Komatsu, 2000; Rakwal et al., 2001; Kim et
al., 2003) and it may increase the emission of volatiles.
• Exogenous application of MeJA increases the release of
volatile organic compounds (Halitschke et al., 2000),
which enhances the mortality rates of the herbivores by
attracting the natural enemies of herbivores (Kessler and
Baldwin 2001).

38.
48

39.
Plant lack an immune system like in animals but posses mechanism
that recognizes potential pathogens and initiate defense responses.
During their biochemical evolution, the plants are devised with
certain magic molecules of defense (secondary metabolites) like JAs
Recent insights in to the Jas mediated plant defense cascade and
knowledge of key regulators of this will help us to design future
crops with increased biotic stress resistance and better adaptability.
Higher crop yields might be achieved by increasing the
pathogen/ insect resistance which can be achieved by manipulating
the expression of the key genes involved in Jas biosynthesis and
signaling cascades

40.
Nature has blessed me
with Defense mechanism