Methanol and ethanol modulate responses to danger- and microbe-associated molecular patterns

Area of Science:

• Plant Biology
• Plant Physiology
• Molecular Plant-Microbe Interactions

Background:

• Methanol is released from plant cell walls by pectin methylesterases (PMEs).
• PMEs are involved in plant development and defense against pathogens and herbivores.
• The role of methanol in plant defense signaling is not well understood.

Purpose of the Study:

• To investigate the effects of exogenously supplied methanol on plant defense signaling pathways.
• To determine if methanol acts as a signaling molecule in plant responses to DAMPs and MAMPs.
• To compare methanol's effects in dicot and monocot species.

Main Methods:

• Treatment of plant cells, seedlings, and leaf tissues with methanol and various DAMPs/MAMPs (systemin, flg22, chitosan).
• Measurement of MAP kinase (MAPK) activity and oxidative burst.
• Analysis of defense gene expression (PR-1, PI-1).

Main Results:

• Methanol alone had weak effects on defense signaling in dicots but significantly altered responses to DAMPs/MAMPs.
• Methanol altered the kinetics and amplitudes of DAMP/MAMP-induced MAPK activity and oxidative burst in tobacco, tomato, and Arabidopsis.
• Methanol suppressed defense gene expression in tomato and activated MAPK signaling in grasses (tall fescue, darnel grass).
• Ethanol showed similar effects to methanol on DAMP/MAMP responses.

Conclusions:

• Methanol can be perceived by plants as a 'damaged self' signal.
• In dicots, methanol acts as a DAMP-like alarm signal with low elicitor activity.
• In monocot grasses, methanol functions as an elicitor-active DAMP.
• Methanol and ethanol modulate plant defense signaling pathways, suggesting a role in plant stress responses.