Biology subjects

Urbany, C.

Publications and source records attributed to Urbany, C..

5 recordsLinked to original sources

bioRxiv2026

Genetic analysis of maize seedling root traits under chilling highlights their importance for early field development

Characterizing the genetic basis of root system architecture and its role in early plant development is essential for developing maize varieties with improved nutrient uptake, enhanced early vigour, and higher yield potential in temperate regions. Landraces represent an invaluable source of allelic diversity that can be leveraged to enrich the genetic basis of modern breeding material. In this study, we used a high throughput phenotyping platform to characterize genetic variation for seedling root traits under chilling conditions relevant for early plant establishment in a large doubled haploid (DH) library derived from two European maize landraces. We dissected the quantitative genetic architecture of twelve seedling root traits using a haplotype-based genome-wide association study, identifying large-effect haplotypes specific to the individual landraces as well as numerous small-effect haplotypes present in both landraces. We validated the effects of four QTL in a biparental population, demonstrating their stability across genetic backgrounds. We found highly significant correlations between haplotype effects on seedling root traits evaluated in the phenotyping platform and early plant height evaluated in multi environment field trials, demonstrating the relevance of seedling root architecture for early plant establishment. In particular, haplotypes associated with seminal and lateral root length were the major determinants of early plant height under field conditions. Several of the haplotypes increasing seedling root length were absent from a broad panel of flint breeding lines, highlighting their potential as targets for introgression to improve early plant establishment under temperate growing conditions. Key messageSeedling root QTL discovered in a high throughput phenotyping platform under chilling conditions influence early plant development in the field.

genetics↗

bioRxiv2026

Genetic Dissection of Grain Yield and Correlated Proxy Traits Under Suboptimal Conditions

Securing sustainable crop production requires the genetic improvement of abiotic stress tolerance. Due to the broad range of environmental factors causing abiotic stress and complex genotype-by-environment interactions, it is crucial to understand the genetic basis of crop yield under suboptimal conditions. Here, we developed a dent maize Multi-parent Advanced Generation Inter-Cross (MAGIC) population comprising 388 doubled haploid (DH) lines. The population was derived from eight founders with varying stress tolerance, selected from a dent diversity panel evaluated for yield performance across a wide range of European environments. The MAGIC DH lines were genotyped via whole-genome sequencing ([~]5X coverage) and evaluated in seven testcross and 14 line per se trials, for grain dry matter yield, leaf senescence, leaf rolling, anthesis-silking interval, and six additional agronomic traits. Genetic dissection identified 22 grain yield QTL, explaining 45% of the genetic variance. Under heat and drought stress, testcross grain yield correlated significantly with leaf senescence and leaf rolling measured in line per se trials. Bivariate multi-trait analysis showed that alleles for delayed senescence and reduced rolling at detected QTL generally exhibited positive effects on grain yield, suggesting that accumulating these favorable alleles could enhance yield performance. Incorporating these proxies into multi-trait genomic prediction models improved yield prediction accuracy, although gains were constrained by modest trait correlations. Given the comprehensive data, we also provide recommendations for optimizing sequencing depth and QTL mapping strategies in experimental maize populations. Key messageThis eight-founder MAGIC population represents a powerful resource for dissecting complex traits in maize, assessing the utility of drought proxy traits, and optimizing low-coverage whole-genome sequencing approaches.

genetics↗

bioRxiv2025

Structural variation at lhcb6 underlies genetic variation in photosystem II maximum quantum efficiency in maize

Targeted utilization of native genetic diversity can expand the genetic basis of traits that exhibit limited genetic variation in elite breeding material and can enhance our understanding of the genotype-phenotype relationships associated with complex traits in crops. In a genome-wide association study in a European maize landrace we identified quantitative trait loci (QTL) that affected the maximum quantum efficiency of photosystem II (Fv/Fm) in field experiments. In a forward genetic approach, we focused on a QTL on chromosome 10, explaining a large proportion of the genetic variance for Fv/Fm in growth stages V4 (35%) and V6 (47%), for genetic dissection and candidate gene discovery. Integrating molecular and physiological information we show that allelic variation at the gene encoding LIGHT HARVESTING CHLOROPHYLL A/B BINDING PROTEIN6 (LHCB6), a component of the photosystem II (PSII) light-harvesting complex (LHCII) antenna, underlies the variation in Fv/Fm. We demonstrate that the allelic variation results from a hAT transposon insertion at lhcb6 and is associated with differential accumulation of the LHCII antenna components LHCB6 and LHCB3, leading to differences in non-photochemical quenching (NPQ) and plant biomass accumulation. Based on proteomic analyses we propose candidate genes that compensate the unfavorable effects caused by impaired LHCII antenna assembly. Our work provides novel insights into the function of lhcb6 in the context of LHCII antenna assembly and demonstrates the value of natural variation in landraces for the understanding and genetic improvement of complex photosynthetic processes.

genetics↗

bioRxiv2025

Genetic architecture and functional consequences of lateral root length in maize (Zea mays L.)

Understanding the genetic basis of root architecture and its relevance for crop productivity can contribute to the sustainable intensification of agriculture. Leveraging the phenotypic and allelic diversity of an Austrian maize landrace, we dissected the genetic basis of lateral root (LR) length across developmental stages. LR length, a relevant trait for breeding resource-efficient varieties, showed high heritability in our experiments. We discovered eight quantitative trait loci (QTL) for LR length at the reproductive stage R2, overlapping with four QTL at stage R6 but not with QTL detected at vegetative stage V6, suggesting that the genetic regulation of LR length might differ in vegetative and reproductive stages. We fine-mapped qlr1, the most significant QTL for LR length, to a region of 2.3 Mb containing 46 annotated genes. Based on whole-genome sequence and comparative genomics analyses we suggest a candidate gene underlying qlr1. Additionally, we examined the impact of nitrogen, phosphorus, and irrigation treatments on root and shoot development, finding that LR length positively correlates with biomass accumulation under optimal nutrient supply but not under nitrogen stress. Our work provides insights into the genetic regulation of LR length in maize and its relevance for the adaptation to specific growing environments. HighlightMultiple QTL affect lateral root length in maize at different developmental stages. The correlation between lateral root length and biomass accumulation varies under diverse field conditions.

genetics↗

bioRxiv2024

Embracing native diversity to enhance maximum quantum efficiency of photosystem II in maize (Zea mays L.)

Sustainability of maize cultivation would benefit tremendously from early sowing but is hampered by low temperatures during early development in temperate climate. We show that allelic variation of subunit M of NADH-dehydrogenase-like (NDH) complex (ndhm1), discovered in a European maize landrace affects several quantitative traits relevant during early development in cold climates through NDH-mediated cyclic electron transport (CET) around photosystem I, a process crucial for photosynthesis. Starting from a genome-wide association study (GWAS) for maximum potential quantum yield of photosystem II in dark-adapted leaves (Fv/Fm) we capitalized on large phenotypic effects of a hAT transposon insertion in ndhm1 on quantitative traits early plant height (EPH), Fv/Fm, chlorophyll content and cold tolerance caused by reduced protein levels of NDHM and associated NDH components. Analysis of the native allelic series of ndhm1 revealed a rare allele of ndhm1 which is associated with small albeit significant effects on maximum potential quantum yield of photosystem II in dark- and light adapted leaves (Fv/Fm, {Phi}PSII) and early plant height compared to common alleles. Our work showcases the extraction of novel, favorable alleles from locally adapted landraces, offering an efficient strategy for broadening the genetic variation of elite germplasm by breeding or genome editing.

plant biology↗