ROLE OF JASMONIC ACID IN PLANT DEVELOPMENT &DEFENCE MECHANISM

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Role of Jasmonic Acid in Plant Development and Defense Response

Speaker : Rakesh SharmaID. 48030

GOVIND BALLABH PANT UNIVERSITY OF AGRICULTUREE&TECHNOLOGY,PANTNAGAR,INDIA DEPARTMENT OF PLANT PHYSIOLOGY

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INTRODUCTION• Novel plant immune

hormone derived from α- linolenic acid.

• Methyl Jasmonate was first time isolated from the essential oil of Jasminum grandiflorum.

• Ubiquitous in plant kingdom and also produced by certain fungi (Lasiodiplodia theobromae).

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Figure 1: Jasmonic acid responses (a) Chewing insects (b) Necrotropic pathogens

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Figure 2. Biosynthesis of jasmonic acid (JA) and (+)-7-iso-JA-L-isoleucine.

5Wang and Wu, 2013

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Mutant

Biochemical Significance Role

Expression of JAs responsive genes

Effects

coi Coronatine Insensitive JA Signaling Reduced

Sensitivity to insect and necrotrophic pathogens increased

fad Defective Fatty Acid Desaturase

JA Biosynthetic

ReducedSensitivity to insect and necrotrophic pathogens increased

cevConstitutive Expression of VSP

JA Signaling IncreasedIncreased sensitivity to biographic pathogens

jar JA Resistant JA Signaling ReducedIncreased sensitivity to necrotrophic pathogens

opr Defective OPDA Reductase

JA Biosynthetic

Reduced Increased sensitivity to insects

jin JA Insensitive JA Signaling Reduced Increased sensitivity to pathogens

Jasmonic acid mutant

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Jasmonic Acid

Perception

8Wasternack and Hause, 2013

Figure3: Jasmonic acid perception via the COI1–JAZ co-receptor complex – mechanisms in JA-induced gene expression.

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Role of Jasmonic Acid in plant defense and

development

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Fig. 4: Schematic overview of the effect of leaf wounding on the interaction of Medicago truncatula with root-colonizing microorganisms. The arbuscular mycorrhiza (AM) with G. intraradices was found to be promoted by repeated leaf wounding, whereas the colonization with the pathogenic oomycete Aphanomyces euteiches was reduced. Both effects might be triggered by the increased levels of jasmonic acid (JA).

Wasternack and Hause 2013.

11Taiz and Zeiger 3rd ed.

Figure 5: Schematic presentation of mechanism of JA in response to Insect attack

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Figure 6: 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

Root Growth Inhibition

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Figure 7: 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

14Wasternack and Hause 2013.

TRICHOME FORMATION

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Flower Development

Fig.8 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.

16Wasternack and Hause 2013.

Senescence

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Diverse functions of jasmonates in rice.

Liu et al., 2015.

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Interaction of Jasmonic Acid with

other hormone

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Schematic representation of the series of events leading to defense activation. When plants are attacked by pathogens or herbivores, different types of receptors, including pattern-recognition receptors (PRRs) and resistance (R) proteins, recognize non-self (or damaged-self) molecular patterns or signals, including pathogen-, damage-, and herbivore-associated molecular patterns (PAMPs, DAMPs, and HAMPS, respectively), as well as effector molecules.

Ballare, 2014

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Fig.9 Schematic overview of the common defense system activated by JA and SA in rice.

Ballare, 2014

22Wasternack and Hause 2013

The cross-talk between jasmonate (JA), ethylene (ET) and abscisic acid (ABA) triggered in response to herbivorous insects and necrotrophic pathogens. Attack by herbivorous insects induces JA- and ABA-dependent signalling pathways, whereas infections by necrotrophic pathogens induce JA- and ET-dependent signalling pathways. Both branches are antagonistically regulated. Solid lines, known interactions; dashed lines, hypothetical interactions; green arrows, positive effects; blue inhibition lines, negative effects. Compounds are given in rectangles, transcriptional regulators in circles, regulated genes in purple. ERF1, ethylene response factor 1; ORA59, octadecanoid-responsive Arabidopsis AP2/ERF-domain protein 59; PYL4, PYR1-like protein 4 (ABA receptor)

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Figure: Model Describing that DELLAs Modulate JA Signaling via Competitive Binding to JAZs.

Hou et al., 2010

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CONCLUSION

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Jasmonic acid & sallicylic acid pathway can be effectively use in biotic &abiotic stress resistance development.

Jasmonic acid & sallicylic acid cascades helps in understanding specific host pathogen interaction strategy .

It can be used in enhancing nutrient uptake under stress condition

It can help in proper growth and development activating factor.

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Future perspective• Plants lack an immune system like in animals but posses mechanism

that recognize potential pathogens and initiate defense responses. During their biochemical evolution, the plants are devised with certain magic molecules of defense like JA.

• Recent insights into the JAs mediated plant defense cascade and better knowledge of key regulation of plant growth and development processes will help us to design future crops with increased biotic stress resistance and better adaptability under changing climate.

• In future, there is need to obtain higher crop yields to fulfill demand of increasing population. It might be achieved by increasing the pathogen/insect resistance by manipulating the expression of the key genes involved in JA biosynthesis and signaling cascades.

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THANK YOU