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Biology subjects

Seth Jon Davis

Publications and source records attributed to Seth Jon Davis.

2 recordsLinked to original sources

Using MinION nanopore sequencing to generate a de novo eukaryotic draft genome: preliminary physiological and genomic description of the extremophilic red alga Galdieria sulphuraria strain SAG 107.79

We report here the de novo assembly of a eukaryotic genome using only MinION nanopore DNA sequence data by examining a novel Galdieria sulphuraria genome: strain SAG 107.79. This extremophilic red alga was targeted for full genome sequencing as we found that it could grow on a wide variety of carbon sources and could uptake several precious and rare-earth metals, which places it as an interesting biological target for disparate industrial biotechnological uses. Phylogenetic analysis clearly places this as a species of G. sulphuraria. Here we additionally show that the genome assembly generated via nanopore long read data was of a high quality with regards to low total number of contiguous DNA sequences and long length of assemblies. Collectively, the MinION platform looks to rival other competing approaches for de novo genome acquisition with available informatics tools for assembly. The genome assembly is publically released as NCBI BioProject PRJNA330791. Further work is needed to reduce small insertion-deletion errors, relative to short-read assemblies.

Genomics

Natural Variants of ELF3 Affect Thermomorphogenesis by Transcriptionally Modulating PIF4-Dependent Auxin Response Genes

Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis. We identified GIRAFFE2.1, a major QTL explaining ~18% of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth. In combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod cues to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.

Plant Biology