Coevolutionary genetic variation in the legume-rhizobium transcriptome.
Katy D Heath1, Patricia V Burke, John R Stinchcombe
1Department of Plant Biology, University of Illinois, 250 Morrill Hall, 505 S. Goodwin Ave., Urbana, IL 61801, USA. kheath@life.illinois.edu
Molecular Ecology
|June 8, 2012
Summary
Reciprocal selection drives coevolution, influenced by genotype × genotype interactions. This study reveals regulatory gene expression changes in legume-rhizobium symbiosis, illuminating molecular routes of coevolution.
Area of Science:
- Evolutionary Biology
- Genetics
- Microbiology
Background:
- Coevolutionary change necessitates reciprocal selection between interacting species.
- Genotype × genotype (G × G) interactions for fitness underpin coevolutionary genetic variation in symbioses.
- The molecular underpinnings of G × G interactions in symbiotic relationships remain largely unexplored.
Purpose of the Study:
- To investigate the molecular basis of G × G interactions in a model legume-rhizobium mutualism.
- To determine how genetic variation influences symbiotic gene expression in interacting species.
- To identify the regulatory mechanisms driving symbiotic gene expression variation.
Main Methods:
- Utilized gene expression microarrays to analyze transcriptomic variation in legume-rhizobium symbiosis.
- Applied quantitative genetic approaches to partition symbiotic transcriptome variation into additive and interactive genetic components.
- Examined the influence of plant and rhizobium genotypes on gene expression patterns and fitness benefits.
Main Results:
- Symbiotic transcriptome variation can be partitioned into additive and interactive genetic components, mirroring quantitative traits like fitness.
- Plant genetic variation significantly influenced nodule gene expression.
- Plant and rhizobium genotype interactions globally shifted rhizobium gene expression, impacting plant fitness benefits.
Conclusions:
- This study provides the first partitioning of genetic variation within a symbiotic transcriptome.
- Uncovered transcriptomic variation implicates regulatory changes in both legume and rhizobium as drivers of symbiotic gene expression.
- Identified potential molecular pathways facilitating coevolutionary change in mutualistic interactions.
Related Concept Videos
03:21Genome Size and the Evolution of New Genes
While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
03:21Genome Size and the Evolution of New Genes
While every living organism has a genome of some kind (be it RNA, or DNA), there is considerable variation in the sizes of these blueprints. One major factor that impacts genome size is whether the organism is prokaryotic or eukaryotic. In prokaryotes, the genome contains little to no non-coding sequence, such that genes are tightly clustered in groups or operons sequentially along the chromosome. Conversely, the genes in eukaryotes are punctuated by long stretches of non-coding sequence.
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...