Biology subjects

Hug, M.

Publications and source records attributed to Hug, M..

3 recordsLinked to original sources

bioRxiv2025

Candidate genes for stem rust resistance in Italian ryegrass revealed by nested association mapping

Stem rust, caused by Puccinia graminis ssp. graminicola, is a major disease affecting the outcrossing species Italian ryegrass (Lolium multiflorum Lam.), leading to substantial reductions in seed yield. Until now, knowledge on the genetic control of stem rust resistance in Italian ryegrass has been limited to a few quantitative trait loci identified in bi-parental mapping populations. To discover novel resistance sources for use in breeding programs, appropriate plant populations, reliable phenotyping methods and advanced genomic tools are essential. In this study, we utilized a previously established F2 nested association mapping (NAM) population comprising 708 individuals derived from 24 founder plants exhibiting high variation in stem rust resistance. Phenotypic evaluation was conducted under natural inoculation in three location-by-year combinations. By integrating reduced-representation sequencing of the NAM population with whole-genome sequencing of the founder plants, we identified 3,199,253 SNP markers for association mapping. The high SNP marker density, together with the strong detection power of the NAM population, enabled the identification of four novel candidate genes. Two of these genes, located on chromosomes 6 and 7, encode receptor-like serine/threonine kinases that are known to play a role in stem rust resistance in other crops. Within the serine/threonine kinase gene Chr7.32208, two superior haplotypes were identified that can be directly implemented as selection criteria in breeding programs. The novel stem rust resistance candidate genes reported here provide promising targets for functional validation and the improvement of stem rust resistance in Italian ryegrass breeding. Key messageField phenotyping of a previously established NAM population for stem rust resistance, combined with high-density genotyping, enabled the identification of novel sources of stem rust resistance in Italian ryegrass.

plant biology↗

bioRxiv2023

Higher seed yield through selection for reduced seed shattering in Italian ryegrass (Lolium multiflorum Lam.)

Seed shattering, i.e., the loss of seeds at ripening stage shortly before or during seed harvest, is strongly reducing seed yield in Italian ryegrass (Lolium multiflorum Lam.). The aim of this study was to evaluate the possibility to reduce seed shattering within breeding germplasm via recurrent phenotypic selection on spaced plants. Starting from a founder population of 300 plants serving as F0 population, two cycles of phenotypic selection for high and low seed shattering were applied and compared to randomly selected individuals on spaced plant level and in plot trials. Comparison of the five resulting populations in a spaced plant trial revealed a significant effect of selection, with lowest seed shattering (15.3%) observed in the population selected twice for decreased shattering (15.3%) and highest seed shattering (47.9%) for the population selected twice for increased shattering. The same ranking of the five F2 populations was observed in a subsequent trial with sown plots. Thus, using the method presented here, recurrent selection on single spaced plants allows to efficiently reduce seed shattering and, therefore, to increase seed yield in swards.

plant biology↗

bioRxiv2017

Synthetic single domain antibodies for the conformational trapping of membrane proteins

Single domain antibodies called nanobodies are excellent affinity reagents for membrane proteins. However, their generation relies on immunizations, which is only amenable to robust proteins and impedes selections in the presence of non-covalent or toxic ligands. To overcome these key limitations, we developed a novel in vitro selection platform, which builds on synthetic nanobodies called sybodies. Inspired by the shape diversity of natural nanobodies, three sybody libraries exhibiting different randomized surface shapes were engineered for high thermal stability. Using ribosome display, exceptionally large libraries were pre-enriched against membrane protein targets and subsequently funneled into a robust phage display process, thereby reducing selection bias. We successfully generated conformation-selective, high affinity sybodies against the human glycine transporter GlyT1, the human equilibrative nucleotide transporter ENT1 and a bacterial ABC transporter. Our platform builds exclusively on commercially available reagents and enables non-specialized labs to generate conformation-specific binders against previously intractable protein targets.

bioengineering↗