Author's personal copy Australasian Plant Pathol. DOI 10.1007/s13313-015-0392-1
REVIEW
Recent insights into the molecular mechanism of jasmonate signaling during insect-plant interaction Archana Singh 1 & Sujata Singh 2 & Indrakant Kumar Singh 2
Received: 28 August 2015 / Accepted: 11 November 2015 # Australasian Plant Pathology Society Inc. 2015
Abstract Amongst all the phytohormones, jasmonates are most important signaling molecule associated with plant defense against herbivores as they activate the expression of both direct and indirect defenses. Jasmonates are produced at insect-infested local sites and either jasmonate itself or some Jasmonic Acid (JA)-elicited compound travels to systemic leaves and elicits defense response. Upon herbivory, receptors/sensors of the host plant recognize Herbivory Associated Molecular Patterns (HAMPs) and early signaling events start with the involvement of Mitogen Activated Protein Kinases (MAPKs). JA biosynthesis is initiated in the chloroplast with the hydrolysis of chloroplast membrane lipids by phospholipases releasing free α-linolenic acid (α-LA), which gets converted to 12-oxo-phytodienoic acid (OPDA). OPDA is subsequently transported to peroxisomes where JA is produced by β-oxidation and it conjugates with isoleucine by JA amino acid synthetase (JAR) enzymes. Once high levels of JA-Isoleucine (Ile) are achieved, JA-induced response is instigated by SCF complex (a complex consisting of Skp1, Cullin-1 and F-box protein). JA-Ile forms a complex to form JA-Ile-COI1 (Coronatine insensitive Protein1) that
* Indrakant Kumar Singh
[email protected] Archana Singh
[email protected] Sujata Singh
[email protected] 1
Department of Botany, Hans Raj College, University of Delhi, Delhi 110007, India
2
Molecular Biology Research Laboratory, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, Delhi 110019, India
recognizes a target protein Jasmonate ZIM domain (JAZ1), which is ubiquitinated and subsequently subjected to proteasomal degradation releasing the repression of MYC2, thereby activating expression of JA responsive genes. Further, both Novel Interactor of JAZ (NINJA) and Topless (TPL) proteins function as negative regulators of jasmonate responses. Although there has been remarkable progress in recent years, many open questions remain to be answered regarding jasmonate signaling during herbivory. Keywords Jasmonates . Herbivory . Induced plant defense . Systemic signaling
Introduction Plants have evolved an intricate and dynamic defense system to combat herbivore attacks that includes constitutive (or ‘static’) and induced (or ‘active) defense mechanisms (Gatehouse 2002). The main components of constitutive defense system are structural barriers and certain chemicals as secondary metabolites. Induced defense systems are activated upon recognition of Herbivore-derived signals. Both constitutive and induced defense system comprise of an array of compounds that function as direct defense by negatively affecting herbivore growth, reproduction and fecundity (Bennett and Wallsgrove 1994). In addition volatile organic compounds cause indirect defense by attracting the natural enemies of herbivores (Kessler and Baldwin 2001; Kessler and Baldwin 2002; Heil 2008). Induced response in plants is one of the most important components of pest control in agriculture, and has been exploited for regulation of insect herbivore population (Howe and Jander 2008; Agrawal 2011). But these defense systems are costly and can compromise plants normal growth and reproduction in dearth of appropriate regulation (Tian
