Genetic architecture of heritable leaf microbes

Area of Science:

• Microbiology
• Ecology
• Genetics

Background:

• Host-associated microbiomes are influenced by environmental factors and host genetics.
• Understanding the genetic basis of these microbiomes is crucial for microbial community assembly and eco-evolutionary dynamics.
• The relative contributions of different types of genetic variation to microbiome structure are not well understood.

Purpose of the Study:

• To investigate the roles of Mendelian and quantitative genetic variation in structuring the leaf microbiome of *Ipomoea hederacea* (ivyleaf morning glory).
• To determine how these genetic variations contribute to microbe heritability.
• To explore if leaf shape, a Mendelian trait, influences phyllosphere microbe abundance.

Main Methods:

• Generation of *Ipomoea hederacea* matrilines with differing quantitative genetic variation and leaf shape.
• Analysis of the leaf microbiome structure in relation to host genetic variation.
• Assessment of microbe heritability across different genetic backgrounds.

Main Results:

• Both Mendelian and quantitative host genetic variations contribute to microbe heritability, despite significant environmental effects.
• Cumulative small-effect genomic differences from matrilines explained microbial variation as much as or more than a single large-effect Mendelian locus.
• Leaf shape was found to contribute to the variation in abundances of certain phyllosphere microbes.

Conclusions:

• The genetic architecture of leaf-associated microbiomes in *Ipomoea hederacea* involves both quantitative genetic variation and Mendelian traits.
• Plant evolution affecting leaf shape or other quantitative genetic loci can potentially alter microbial abundance and community composition.
• Host genetics play a significant role in shaping plant-associated microbial communities.