Using transects to disentangle the environmental drivers of plant-microbiome assembly.

Environmental heterogeneity is a major driver of plant-microbiome assembly, but the specific climate and soil conditions that are involved remain poorly understood. To better understand plant microbiome formation, we examined the bacteria and fungi that colonize wild strawberry (Fragaria vesca) plants in North American and European populations. Using transects as replicates, we found strong overlap among the environmental conditions that best predict the overall similarity and richness of the plant microbiome, including soil nutrients that replicate across continents.

The influence of host genetics on the microbiome.

It is well understood that genetic differences among hosts contribute to variation in pathogen susceptibility and the ability to associate with symbionts. However, it remains unclear just how influential host genes are in shaping the overall microbiome. Studies of both animal and plant microbial communities indicate that host genes impact species richness and the abundances of individual taxa.

Characterizing both bacteria and fungi improves understanding of the Arabidopsis root microbiome.

Roots provide plants mineral nutrients and stability in soil; while doing so, they come into contact with diverse soil microbes that affect plant health and productivity. Despite their ecological and agricultural relevance, the factors that shape the root microbiome remain poorly understood. We grew a worldwide panel of replicated Arabidopsis thaliana accessions outdoors and over winter to characterize their root-microbial communities.

The genetic architecture of freezing tolerance varies across the range of Arabidopsis thaliana.

The capacity to tolerate freezing temperatures limits the geographical distribution of many plants, including several species of agricultural importance. However, the genes involved in freezing tolerance remain largely unknown. Here, we describe the variation in constitutive freezing tolerance that occurs among worldwide accessions of Arabidopsis thaliana.

Genome-wide association study of Arabidopsis thaliana leaf microbial community.

Identifying the factors that influence the outcome of host-microbial interactions is critical to protecting biodiversity, minimizing agricultural losses and improving human health. A few genes that determine symbiosis or resistance to infectious disease have been identified in model species, but a comprehensive examination of how a host genotype influences the structure of its microbial community is lacking. Here we report the results of a field experiment with the model plant Arabidopsis thaliana to identify the fungi and bacteria that colonize its leaves and the host loci that influence the microbe numbers.

Genomic variability as a driver of plant-pathogen coevolution?

Pathogens apply one of the strongest selective pressures in plant populations. Understanding plant-pathogen coevolution has therefore been a major research focus for at least sixty years [1]. Recent comparative genomic studies have revealed that the genes involved in plant defense and pathogen virulence are among the most polymorphic in the respective genomes.

Bacterial communities associated with the leaves and the roots of Arabidopsis thaliana.

Diverse communities of bacteria inhabit plant leaves and roots and those bacteria play a crucial role for plant health and growth. Arabidopsis thaliana is an important model to study plant pathogen interactions, but little is known about its associated bacterial community under natural conditions. We used 454 pyrosequencing to characterize the bacterial communities associated with the roots and the leaves of wild A.

GWAPP: a web application for genome-wide association mapping in Arabidopsis.

Arabidopsis thaliana is an important model organism for understanding the genetics and molecular biology of plants. Its highly selfing nature, small size, short generation time, small genome size, and wide geographic distribution make it an ideal model organism for understanding natural variation. Genome-wide association studies (GWAS) have proven a useful technique for identifying genetic loci responsible for natural variation in A.

Genome-wide patterns of genetic variation in worldwide Arabidopsis thaliana accessions from the RegMap panel.

Arabidopsis thaliana is native to Eurasia and is naturalized across the world. Its ability to be easily propagated and its high phenotypic variability make it an ideal model system for functional, ecological and evolutionary genetics. To date, analyses of the natural genetic variation of A.

Adaptation to climate across the Arabidopsis thaliana genome.

Understanding the genetic bases and modes of adaptation to current climatic conditions is essential to accurately predict responses to future environmental change. We conducted a genome-wide scan to identify climate-adaptive genetic loci and pathways in the plant Arabidopsis thaliana. Amino acid-changing variants were significantly enriched among the loci strongly correlated with climate, suggesting that our scan effectively detects adaptive alleles.

Contrasting mechanisms of secondary metabolite accumulation during leaf development in two tropical tree species with different leaf expansion strategies.

Young leaves of most species experience remarkably higher herbivore attack rates than mature leaves. Considerable theoretical effort has focused on predicting optimal defense and tradeoffs in defense allocation during leaf expansion. Among others, allocation to secondary chemistry may be dependent on growth constraints.