Fungi Indirectly Affect Plant Root Architecture by Modulating Soil Volatile Organic Compounds

Area of Science:

• Plant-microbe interactions
• Microbial volatile organic compounds (VOCs)
• Plant development

Background:

• Microbial volatile organic compounds (VOCs) are known to modulate plant growth.
• Previous studies typically exposed plants to VOCs from microbes grown on nutrient-rich media.
• The role of the growth medium in microbial VOC emission and its effect on plants is not fully understood.

Purpose of the Study:

• To investigate the influence of VOCs from soil-grown Fusarium fungi on Arabidopsis plant development.
• To compare the volatile profiles of Fusarium strains grown in soil versus malt extract.
• To explore a novel mechanism of plant-microbe interaction involving VOC consumption.

Main Methods:

• Cultured Fusarium fungi in soil and malt extract media.
• Exposed Arabidopsis plants to VOCs emitted from these cultures.
• Analyzed volatile profiles using gas chromatography-mass spectrometry.
• Measured changes in Arabidopsis primary root length.

Main Results:

• Distinct volatile signatures were observed for different Fusarium genetic clades and were significantly influenced by the growth medium.
• All soil-grown Fusarium isolates promoted primary root elongation in Arabidopsis.
• This growth promotion was associated with a decrease in VOC concentrations in the soil, suggesting VOC consumption.

Conclusions:

• The growth medium profoundly impacts microbial VOC emission profiles.
• Soil-grown Fusarium fungi can enhance Arabidopsis primary root growth.
• This study presents a paradigm shift, demonstrating that VOC consumption, rather than emission, can mediate plant-microbe interactions and modulate plant development.