Genetic control of root architectural plasticity in maize

Area of Science:

• Plant Genetics and Genomics
• Crop Physiology
• Agricultural Science

Background:

• Root phenotypes are crucial for soil resource acquisition.
• Genetic control and phenotypic plasticity of root traits remain poorly understood.
• Phenotypic plasticity allows plants to adapt to environmental changes.

Purpose of the Study:

• To investigate the genetic control of root architectural phenes' responses to water deficit (stress plasticity) and different environments (environmental plasticity).
• To determine if loci controlling plasticity are distinct from those controlling phene expression.
• To develop a public resource for studying the genetic basis of phenotypic plasticity.

Main Methods:

• Phenotyped root architectural phenes in a large maize association panel under field conditions with and without water deficit stress across multiple seasons and locations (Arizona and South Africa).
• Utilized association mapping to identify candidate genes associated with plasticity and phene expression.
• Compared identified loci for overlap between plasticity and constitutive expression.

Main Results:

• All investigated root phenes exhibited phenotypic plasticity, with varying degrees of response.
• Identified distinct sets of candidate genes for stress plasticity, environmental plasticity, and constitutive phene expression.
• Found minimal overlap between candidate genes controlling plasticity and those controlling phene expression under specific conditions.

Conclusions:

• Phenotypic plasticity in root architecture is a highly quantitative trait.
• Genetic loci controlling plasticity are largely distinct from those controlling phene expression under stress and non-stress conditions.
• The distinct genetic architecture presents challenges for breeding programs aiming to enhance adaptive traits; a new public online resource is provided to aid research.