Biology subjects

Labbancz, J.

Publications and source records attributed to Labbancz, J..

4 recordsLinked to original sources

bioRxiv2026

A Cesium Chloride Gradient Ultracentrifugation-Based Method for the Isolation of DNA from Diverse Recalcitrant Plant Species for Nanopore Sequencing

Developments in Nanopore sequencing have enabled telomere to telomere genomic assembly as a routine technique in genomic research. Nanopore DNA sequencing for genomic assembly is typically performed on native DNA molecules, making it particularly sensitive to the quality of input DNA, with contaminating molecules limiting data yields and reducing read quality. As pangenome analysis gains interest, particularly in non-model plant species which are often rich in inhibitory secondary metabolites, the development of methods which can improve the quality and throughput of nanopore sequencing is essential. Here we describe a method for isolation of total DNA from the leaf tissues of diverse Viridiplantae species. The initial lysis buffer consists of a modified CTAB buffer, incorporating dimethyl sulfoxide for the reduction of viscosity, which can be problematic in many plant DNA preparations. An organic extraction with 2-butoxyethanol is utilized to further extract phenolic compounds which may be sufficiently hydrophilic to evade chloroform extraction, while reducing aqueous phase volume. Further cleanup via cesium chloride (CsCl) ultracentrifugation is performed to minimize the carryover of residual contaminating macromolecules. Samples prepared using this method are of consistent high quality, even when extracted from challenging late season leaf tissue or secondary metabolite rich species. Sequencing results from samples prepared by this method outperform those obtained from typical modified CTAB DNA isolation techniques in both quantity and quality. We tested sequencing performance from Vitis DNA isolated using a modified CTAB method and Vitis DNA isolated using the CsCl ultracentrifugation-based method described here. DNA isolated via the method described here produced 83% more >Q10 sequence data (52.61 Gb vs. 28.8 Gb), resulted in a 60% greater read N50 despite more handling steps (32.78kb vs. 20.45kb), and resulted in a higher modal read quality (Q27 vs. Q24). The consistency of this method across diverse plant taxa suggests its use as a general method for DNA isolation prior to Nanopore sequencing and genomic assembly for diverse plant taxa.

molecular biology↗

bioRxiv2026

Extensive Novel Genomic Variations in Mutant European Pear Individuals Revealed by Mapping to a Pangenome Reference

European pear (Pyrus communis) is the most widely cultivated Pyrus species outside of Asia; however, production has been declining in Europe, Oceania, and North America. Most European pear cultivars are over 100 years old and face pressure from disease, a changing climate, and challenging postharvest characteristics, while demand for increased production efficiency rises. To generate germplasm with desirable characteristics to address these concerns, a mutation breeding approach was chosen, with crosses made between four economically significant cultivars ( Bartlett, dAnjou, Abbe Fetel, and Comice) using gamma-irradiated pollen. This resulted in 49 viable offspring, of which 37 have survived at least 10 years. Nanopore whole-genome sequencing was used to test the success of this approach and screen for variants of interest. Sequence reads were mapped to both a lightweight, purpose-built pangenome derived from assemblies of parental haplotypes and a linear reference genome, enabling the high-quality discovery of variants of all sizes, ranging from single-base substitutions to megabase-scale deletions, with the overwhelming majority being small variants. The overall rate of mutation was 153 novel small variants and 0.228 novel structural variants per Gray of absorbed gamma radiation. Alternate ploidy levels were detected in four lines, which included three triploids and one tetraploid. While the resulting individuals appear incapable of floral development, they may be of utility as rootstock cultivars and a valuable genetic resource for understanding the underlying basis of structural traits.

genomics↗

bioRxiv2026

Pangenome Analysis of Pyrus Reveals Potential Role of Transcription Factors in Recent Adaptation to Arid Environments

Pears (genus Pyrus) are among the most extensively cultivated tree fruits with a wide-reaching economic impact. Despite this, the genetic basis of most pear traits of interest, including abiotic stress tolerance, tree architecture, precocity, parthenocarpy, disease resistance, and fruit ripening, remains poorly understood. Although extensive efforts have been made to identify quantitative trait loci (QTLs) that explain the genetic basis of pear traits, many are poorly transferable, limiting their utility for informing genetic improvement or management of pears across most genetic backgrounds. To provide a whole-genome context and enable the exploration of functional variation in Pyrus, we developed a pangenome graph using 31 accessions representing 23 Pyrus species from the National Clonal Germplasm Repository. Whole-genome sequencing was performed solely with Oxford Nanopore, generating highly contiguous assemblies for pangenome construction, demonstrating the viability of a single-platform approach to pangenomic analysis in Viridiplantae. Exploration of the pangenome graph reveals genes present in some lineages, with potential functional implications. A group of arid-adapted Pyrus species exhibits signs of selective sweeps in regions associated with transcription factors, likely impacting abiotic stress tolerance. With the development of this pangenomic resource, resequencing analysis in Pyrus is now possible without the limitations imposed by single-reference genome assemblies.

genomics↗

bioRxiv2025

Both conventionally and organically fertilized tomatoes maintain fruit quality through uncontrolled green peach aphid infestation, with a transcriptional shift towards catabolism

Aphids are a major pest of greenhouse-grown temperate crops, responsible for billions in crop damage yearly. As organic agriculture rapidly grows in popularity, understanding how plants grown under organic systems respond to insect pest pressure may give insights into better management practices and information about the genes of interest for crop improvement. We measured the response of tomato (Solanum lycopersicum) leaf and fruit transcriptome, as well as a few selected metabolites in the mature fruit, to an infestation of the generalist green peach aphid (Myzus persicae). The aphids were introduced approximately halfway through the lifecycle of the plants that were grown under conventional and organic fertilizer regimes. While plants provided with conventional fertilizer experienced greater aphid infestation, neither group suffered a significant loss in total yield or fruit quality. This result is likely a consequence of ample nutrient and water availability. Co-expression network analysis using WGCNA revealed that in leaf tissue, both treatment groups showed a general shift from diverse anabolic processes to catabolism, while fruit tissue experienced relatively minor changes. At the stage of infestation investigated, abscisic acid appeared to be the main phytohormone response. One coexpression network module showed a correlation with both organic fertilizer treatment and aphid infestation; its hub gene (Solyc02g078940.3) may be of interest in exploring unique responses to phloem feeding insect infestation under an organic production regime.

plant biology↗