Biology subjects

Dorn, K.

Publications and source records attributed to Dorn, K..

8 recordsLinked to original sources

bioRxiv2024

Different serotonergic neurons regulate appetite for sucrose and hunger for proteins

For the organism it is important to replenish internal energy storages selectively and selective appetite for nutrients might uncover internal energy requirements. How is the selective uptake of a specific nutrient regulated? Here we show that in Drosophila melanogaster different sets of serotonergic neurons regulate appetite for sucrose and hunger for proteins. Increased neuronal activity in specific subsets of serotonergic neurons and interfering with serotonin reuptake using a mutated serotonin transporter reduced the appetite for sucrose selectively, but not the hunger for proteins. The insulin receptor together with the serotonin transporter regulates the selective sucrose appetite. We provide evidence that the cellular location of the serotonin transporter depends on the insulin receptor. This mechanism might allow optimizing nutrient intake and in turn might prevent overconsumption by repressing appetite for sucrose. Given the conserved nature of the molecules involved it is likely that the mechanism is conserved in higher organisms.

neuroscience↗

bioRxiv2024

A fully phased, chromosome-scale genome of sugar beet line FC309 enables the discovery of Fusarium Yellows resistance QTL

Sugar beet (Beta vulgaris L.) is a global source for table sugar and animal fodder. Here we report a highly contiguous and haplotype phased genome assembly and annotation for sugar beet line FC309. Both assembled haplomes for FC309 represent the largest and most contiguous assembled beet genomes reported to date, as well as gene annotations sets that capture over 1500 additional protein-coding loci compared to prior beet genome annotations. These new genomic resources were used to identify novel quantitative trait loci (QTL) for Fusarium Yellows resistance from the FC309 genetic background using an F2 mapping-by-sequencing approach. The highest QTL signals were detected on Chromosome 3, spanning approximately 10 Mbp in both haplomes. A parallel transcriptome profiling experiment identified candidate genes within the Chromosome 3 QTL with plausible roles in disease response, including NBS-LRR genes with expression trends suggestive of their role as causal resistance genes. Collectively, the genomic resources for FC309 presented here be foundational tool for comparative genomics, mapping other traits in the FC309 background, and as a reference genome for other beet studies due to its contiguity, completeness, and high-quality gene annotations.

plant biology↗

bioRxiv2024

A standard area diagram for Fusarium yellows rating in sugar beet (Beta vulgaris L.)

Members of the Fusarium oxysporum species complex are pathogens of sugar beet causing Fusarium yellows. Fusarium yellows can reduce plant stand, yield, and extractable sugar. Improving host plant resistance against Fusarium-induced diseases, like Fusarium yellows, represents an important long-term breeding target in sugar beet breeding programs. Current methods for rating Fusarium yellows disease severity rely on an ordinal scale, which limits precision for intermediate phenotypes. In this study, we aimed to improve the accuracy and precision of rating Fusarium yellows by developing a standard area diagram (SAD). Two SAD versions were created using images of sugar beets infected with Fusarium oxysporum strain F19. Each version was tested using inexperienced raters. Comparing both the pilot and improved version showed no statistical differences in Lins Concordance Correlation Coefficient (LCC) values to assess accuracy and precision between the two versions (Cb = 0.99 for both versions, {rho}c = 0.97 and 0.96 for version 1 and 2, respectively). In addition, five naive Bayesian machine learning models which used pixel classification to determine disease score, were tested for congruency to human estimates in version 2. Root mean square error was lowest compared to the "true" values for the unweighted model and a model where necrotic tissue was given a 2x weight (12.4 and 12.6, respectively). The creation of this standard area diagram enables breeding programs to make consistent, accurate disease ratings regardless of personnels previous experience with Fusarium yellows. Additionally, more iterations of pixel quantification equations may overcome accuracy issues for rating Fusarium yellows.

plant biology↗

bioRxiv2023

Octopamine integrates the status of internal energy supply into the formation of food-related memories

The brain regulates food intake in response to internal energy demands and food availability. However, can internal energy storage influence the type of memory that is formed? We show that the duration of starvation determines whether Drosophila melanogaster forms appetitive short-term or longer-lasting intermediate memories. The internal glycogen storage in the muscles and adipose tissue influences how intensely sucrose associated information is stored. Insulin-like signaling in octopaminergic reward neurons integrates internal energy storage into memory formation. Octopamine, in turn, suppresses the formation of long-term memory. Octopamine is not required for short-term memory, because octopamine-deficient mutants can form appetitive short-term memory for sucrose and to other nutrients depending on the internal energy status. The reduced positive reinforcing effect of sucrose at high internal glycogen levels combined with the increased stability of food-related memories due to prolonged periods of starvation could lead to increased food intake.

neuroscience↗

bioRxiv2023

Registration of sugar beet genetic stocks FC308 (PI701378) and FC309 (PI700990)

Sugar beet (Beta vulgaris L.) genetic stock lines FC308 (PI701378) and FC309 (PI700990) are two highly homozygous and phenotypically homogenous sources of resistance to two sugar beet pests. FC308 is resistant to sugar beet cyst nematode (Heterodera schachtii), but susceptible to Fusarium yellows, while FC309 is Fusarium yellows resistant, but sugar beet cyst nematode susceptible. These two populations were developed by the USDA-ARS in Fort Collins, CO, derived from unreleased USDA-ARS Salinas germplasm lines. Multiple field and greenhouse trials for Fusarium yellows and nematode resistance confirmed the uniform phenotypes of both lines for each disease. To enable molecular breeders to rapidly screen proprietary markers in silico, gene space assemblies for each line were also developed. Genome sequencing of individual plants from each line, as well as pooled sequencing of sub-populations of both lines indicated fixation of a previously reported genetic variant linked to sugar beet cyst nematode resistance in FC308. However, two previously reported variants linked to Fusarium resistance appear to be unlinked to the resistance found in FC309. Collectively, these two new genetic stocks should prove useful as sources of resistance to Fusarium yellows and sugar beet cyst nematode, as model genetic backgrounds for studying plant-pathogen interactions, and for mapping the resistance genes present in these lines.

plant biology↗

bioRxiv2021

Chromosome-level Thlaspi arvense genome provides new tools for translational research and for a newly domesticated cash cover crop of the cooler climates

Thlaspi arvense (field pennycress) is being domesticated as a winter annual oilseed crop capable of improving ecosystems and intensifying agricultural productivity without increasing land use. It is a selfing diploid with a short life cycle and is amenable to genetic manipulations, making it an accessible field-based model species for genetics and epigenetics. The availability of a high quality reference genome is vital for understanding pennycress physiology and for clarifying its evolutionary history within the Brassicaceae. Here, we present a chromosome-level genome assembly of var. MN106-Ref with improved gene annotation, and use it to investigate gene structure differences between two accessions (MN108 and Spring32-10) that are highly amenable to genetic transformation. We describe small RNAs, pseudogenes, and transposable elements, and highlight tissue specific expression and methylation patterns. Resequencing of forty wild accessions provides insights into genome-wide genetic variation as well as QTL regions for flowering time and a seedling color phenotype. Altogether, these data will serve as a tool for pennycress improvement in general and for translational research across the Brassicaceae.

plant biology↗

bioRxiv2020

A contiguous de novo genome assembly of sugar beet EL10 (Beta vulgaris L.)

A contiguous assembly of the inbred EL10 sugar beet (Beta vulgaris ssp. vulgaris) genome was constructed using PacBio long read sequencing, BioNano optical mapping, Hi-C scaffolding, and Illumina short read error correction. The EL10.1 assembly was 540 Mb, of which 96.7% was contained in nine chromosome-sized pseudomolecules with lengths from 52 to 65 Mb, and 31 contigs with a median size of 282 kb that remained unassembled. Gene annotation incorporating RNAseq data and curated sequences via the MAKER annotation pipeline generated 24,255 gene models. Results indicated that the EL10.1 genome assembly is a contiguous genome assembly highly congruent with the published sugar beet reference genome. Gross duplicate gene analyses of EL10.1 revealed little large-scale intra-genome duplication. Reduced gene copy number for well-annotated gene families relative to other core eudicots was observed, especially for transcription factors. Variation in genome size in B. vulgaris was investigated by flow cytometry among 50 individuals drawn from EL10 progeny and three unrelated germplasm accessions, producing estimates from 633 to 875 Mb/1C. Read depth mapping with short-read whole genome sequences from other sugar beet germplasm suggested that relatively few regions of the sugar beet genome appeared associated with high-copy number variation.

genomics↗

bioRxiv2019

Progress toward the identification and stacking of crucial domestication traits in pennycress

The oilseed species Thlaspi arvense (pennycress) is being domesticated as a new crop that can provide both important ecosystem services and intensify farmland output. Through the use of high throughput sequencing and phenotyping, along with classical mutagenesis key traits needed for pennycress domestication have been identified. Domestication traits identified herein include reduced pod shatter, early maturity, reduced seed glucosinolate levels, and improved oil fatty acid content. By taking advantage of pennycress close genetic relationship with Arabidopsis thaliana, the causative mutations responsible for each of these traits have been identified. These mutations have been used to develop molecular markers to begin to stack the traits into individual lines.

plant biology↗