Natural Product Modulators of Stress Response

Technology #ua05-019

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Thomas Turbyville
Doctoral Student, Arid Lands Studies
Kithsiri Wijeratne
Assistant Research Scientist, Natural Resources and the Environment
Luke Whitesell
Leslie Gunatilaka
Professor, Natural Resources and the Environment
Managed By
Rakhi Gibbons
Asst. Director, Life Sciences (520) 626-6695

Title: Potent Fungal Metabolite Enhances Thermotolerance in Plants

Background: Investigators at The University of Arizona have identified a microbial metabolite produced by a plant-associated fungal strain that could potentially allow plants to withstand stressful abiotic conditions in extreme environments.  Desert ecosystems are characterized by hot, dry and salt-rich conditions unsuitable for many plants.  Specific physical and structural adaptations have evolved to allow many of the plants inhabiting the desert to thrive under such adverse conditions. It now appears that developing symbiotic relationships with microorganisms such as fungi and bacteria may also be an important strategy adopted by desert plants to enhance their survival.

The Technology: In response to many stresses, including heat, oxidizing conditions, and exposure to toxic compounds, plant cells up-regulate an evolutionarily conserved set of helper molecules known as heat shock proteins (Hsp).  Increased expression of these proteins protects the organism against stress-induced damage.  The investigators have isolated a secondary metabolite produced by a desert plant-associated fungus that enhances thermotolerance in the model plant, Arabidopsis thaliana, by increasing heat shock protein levels. The metabolite acts by binding specifically to the protein Hsp90, thereby altering its activity and activating a cascade of events known as the heat shock response that leads to thermotolerance in plants. 

As part of the heat shock response, the metabolite increases cellular levels of Hsp101, a protein that is essential in enhancing the ability of plants to withstand high temperatures.  Studies indicate that increased expression of Hsp101 is dependent on the relative amount of the metabolite present.  In addition, modulation of the plant heat shock response by this metabolite was found to be rapid, adjustable according to needs and reversible.  The mechanism of action and properties of the metabolite suggest that it may play an important role in helping plants to adapt to stressful abiotic conditions. 

*Produced by a fungus shown to enhance thermotolerance in plants.
*Modulator of Hsp90 that initiates a cascade of events leading to induction of the cellular heat shock response
*Enhances thermotolerance rapidly in a dose-dependent and reversible fashion.