Community Assembly and Stability in the Root Microbiota During Early Plant Development

Area of Science:

• Plant science
• Microbiology
• Ecology

Background:

• The plant microbiome plays a crucial role in plant health and development.
• Understanding how environmental factors shape the plant microbiome is essential for agricultural and ecological applications.
• The influence of life-stage events, such as soil exposure timing, on root microbial community assembly remains largely unexplored.

Purpose of the Study:

• To investigate whether the timing of root exposure to microbial communities or priority effects from early colonizers determine the root microbiota composition in mature plants.
• To elucidate the impact of inoculation timing on bacterial and fungal root communities.
• To assess the role of established microbiota in mediating the colonization of new microbes.

Main Methods:

• Two experiments were conducted manipulating the timing of root exposure to a common soil inoculum.
• Priority effects were tested by challenging established root communities with new microbial inocula.
• Bacterial and fungal root communities were analyzed in plants of different ages and colonization histories.

Main Results:

• Root microbiota composition in mature plants was significantly affected by the timing of soil exposure.
• Plants could acquire new microbial associates even with pre-existing root communities.
• Receptivity to new colonizers was limited to one week post-germination for already colonized plants.

Conclusions:

• The timing of soil exposure during early plant life stages is a critical determinant of root microbiota composition in mature plants.
• Priority effects play a role, but the temporal window for microbial colonization is narrow.
• These findings highlight the importance of early-life environmental conditions in shaping the plant microbiome.