The JAZ(Z) of jasmonates: exploring the JA-signaling pathway employing rationally designed jasmonate analogues

• Applicant: Dr. Guillermo Hugo Jimenez-Aleman
• Subject Area: Plant Physiology ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 388965345

The supply of food and (bio-) energy has become a huge challenge for modern society. One of the solutions to this problem can be innovation in plant research aiming to produce higher crop yields and plants more resistant to biotic and abiotic stresses. Understanding the control of plants over their physiological processes may help to design and develop new strategies for a more environmentally friendly and sustainable agriculture.Plants produce hormones, proteins and defense-compounds in response to environmental cues. Many plant responses to biotic and abiotic stressors are coordinated by phytohormones, of which jasmonates play a central role. Jasmonates are lipid-derived compounds with jasmonic acid (JA) as a basic constituent. JA-Ile is the isoleucine conjugate of JA and it is the most bioactive jasmonate controlling the majority of the JA-associated responses in higher plants. JA-Ile-lactones are two novel synthetic JA-Ile analogues which seem to act in a ‘similar’ manner to JA-Ile in vivo. JA-Ile-lactones can selectively induce nicotine accumulation in wild tobacco plants, but fail inducing some other JA-inducible secondary metabolites. Additionally, plants treated with JA-Ile-lactones do not show classical growth reduction as when they are treated with JA-Ile (growth reduction is observed in higher plants when the plant immune system is activated either in response to environmental challenges or by application of jasmonates, e.g. JA-Ile). Furthermore, JA-Ile-lactones potentiated plant growth at early developmental stages and simultaneously provided protection to the tobacco plants against insect herbivores. It is hypothesized that the capability of JA-Ile-lactones to promote degradation of particular plant proteins (JAZ) controls singular aspects of plant responses downstream to lactone perception (via SCFCOI1 receptor complex) by the plant. In this project it is proposed to employ pharmacochemical, molecular and computational tools to explore, in A. thaliana, the molecular basis of plant responses elicited by the synthetic JA-Ile-lactones. Employing JA-Ile-lactones as molecular probes, the singularities in the perception and signaling mechanism of these compounds will be studied in detail. Working with A. thaliana as the model plant will help to verify to which extent the phenomena observed in wild tobacco can be generalized to higher plants. Furthermore, the possibility that JA-Ile-lactones or an analogous jasmonate exist in nature will be explored as well. Understanding the mode of action of these new JA-Ile-derivatives will contribute to the better understanding of the JA-signaling pathway and may help to reveal how plants maintain their ability to grow while protecting themselves against pathogens and herbivore attacks. Moreover, JA-Ile-lactones might constitute a new class of small molecules with potential utilization as semi-bio crop protecting agents and/or molecular probes to study plant signaling.

• DFG Programme: Research Fellowships
• International Connection: Spain
• Host: Professor Dr. Roberto Solano