Adaptive phenotypic divergence in an annual grass differs across biotic contexts

Area of Science:

• Plant biology
• Ecology
• Evolutionary biology

Background:

• Species interactions, specifically rhizosphere biota, can modify how genetic variation influences traits.
• Understanding these interactions is crucial for comprehending adaptation to climate change.

Purpose of the Study:

• To investigate how rhizosphere biota affect trait expression and genetic variation in teosinte populations along an elevational gradient.
• To determine if trait divergence in teosinte is due to adaptation or genetic drift, and the role of soil microbes.

Main Methods:

• Sampling teosinte populations and their rhizosphere biota across an elevational gradient.
• Growing teosinte families in different soil microbial communities to assess trait expression and genetic variation.
• Analyzing trait divergence in relation to environmental adaptation and microbial influence.

Main Results:

• Environmental adaptation shaped divergence in traits like flowering time and root biomass in teosinte.
• Rhizosphere biota altered the expression of these traits and modified within-population genetic variance and covariance.
• Microbial communities influenced phenotypic plasticity and the evolutionary trajectory of teosinte.

Conclusions:

• Rhizosphere communities play a significant role in mediating plant adaptation to environmental changes.
• Changes in trait expression and covariance due to soil biota may have historically influenced teosinte adaptation.
• These microbial interactions are likely to be important in future plant responses to selection pressures.