Effect on microorganisms of volatile compounds released from germinating seeds

Area of Science:

• Microbiology
• Plant Science
• Biochemistry

Background:

• Germinating seeds release volatile organic compounds (VOCs).
• The role of these seed-derived VOCs in supporting microbial growth is not fully understood.
• Understanding microbial responses to seed VOCs is crucial for soil ecology and plant-microbe interactions.

Purpose of the Study:

• To investigate the ability of volatile compounds from germinating seeds to support microbial growth.
• To identify the specific microorganisms that benefit from these seed volatiles.
• To determine the chemical nature of the active volatile components.

Main Methods:

• Germinating seeds of various plants (slash pine, bean, cabbage, corn, cucumber, pea) were used.
• Microbial growth was assessed in mineral salts media using turbidimetry for bacteria and dry mycelial weight for fungi.
• Volatiles were treated with potassium permanganate (KMnO4) and hydrazone to identify active components.

Main Results:

• Seed volatiles significantly increased the growth of several bacterial species (e.g., Pseudomonas fluorescens, Bacillus cereus) and fungal species (e.g., Mucor mucedo, Trichoderma viride).
• Not all tested microorganisms (e.g., Sarcina lutea, Serratia marcescens) showed increased growth.
• Trichoderma viride spore germination was enhanced; effects were limited to the initial days of growth.
• Active components were identified as oxidizable organic compounds, primarily aldehydes.
• Volatiles were absorbed by non-sterile soil and activated charcoal but not by sterile soil or water.

Conclusions:

• Germinating seed volatiles, particularly aldehydes, serve as a carbon source supporting the growth of specific soil microorganisms.
• These findings elucidate the initial microbial colonization dynamics around germinating seeds.
• Seed VOCs play a significant role in shaping early-stage microbial communities in the soil environment.