Biology subjects

Sela, H.

Publications and source records attributed to Sela, H..

4 recordsLinked to original sources

bioRxiv2026

Characterization of a major thrashabilly locus in tetraploid wheat

The transition from hulled to free-threshing grain was a pivotal event in wheat domestication, enabling efficient harvesting and processing. Threshability in tetraploid wheat is controlled primarily by the Q locus and two Tenacious glume (Tg) loci on chromosomes 2A and 2B, yet the molecular basis of the major Tg1-B locus remains incompletely characterized. Here, we phenotyped a durum wheat x wild emmer wheat (WEW) recombinant inbred line (RIL) population across two field environments and performed QTL analysis for glume tenacity (TG), threshability ratio (THRR), and seed number per spike (SDNPS). A total of 19 significant QTLs were detected across six chromosomes. The largest-effect loci for both TG and THRR co-localized on chromosome 2B, with LOD scores up to 14.22 and phenotypic variance explained up to 31.2%, corresponding to the previously described Tg1-B locus. To validate this QTL, the donor RIL was backcrossed three times to Svevo to generate a near-isogenic line, NIL-65 (BC3F5), confirmed by whole-genome skim sequencing to carry a homozygous WEW introgression at Tg1-B. A segregating BC4F2 population derived from NIL-65 confirmed that plants homozygous for the dominant Tg1-B allele displayed significantly higher glume tenacity and intact glume morphology compared to tg1-B sister lines, which exhibited basal glume cracking characteristic of the free-threshing phenotype. Genotyping-by-sequencing delimited the causal interval to an approximately 11 Mb introgression on chromosome 2B. These results confirm the major role of Tg1-B in determining glume tenacity in tetraploid wheat, provide a validated near-isogenic germplasm resource, and lay the foundation for fine-mapping and functional characterization of the underlying gene(s).

plant biology↗

bioRxiv2022

Long-read genome sequencing accelerated the cloning of Pm69 by resolving the complexity of a rapidly evolving resistance gene cluster in wheat

Gene cloning in repeat-rich polyploid genomes remains challenging. Here we describe a strategy for overcoming major bottlenecks in the cloning of the powdery mildew (Pm) resistance gene (R-gene) Pm69 derived from tetraploid wild emmer wheat (WEW). A conventional positional cloning approach encountered suppressed recombination due to structural variations, while chromosome sorting yielded an insufficient purity level. A Pm69 physical map, constructed by assembling ONT long-read genome sequences, revealed a rapidly evolving nucleotide-binding leucine-rich repeat (NLR) R-gene cluster. A single candidate NLR was identified within this cluster by anchoring RNASeq reads of susceptible mutants to ONT contigs and was validated by the virus-induced gene silencing (VIGS) approach. Pm69, comprising Rx_N with RanGAP interaction sites, NB-ARC, and LRR domains, is probably a newly evolved NLR discovered only in one location across the WEW distribution range in the Fertile Crescent. Pm69 was successfully introgressed into durum and bread wheat, and a diagnostic molecular marker could be used to accelerate its deployment and pyramiding with other resistance genes.

genetics↗

bioRxiv2022

The genetic structure of a wild wheat population has remained associated with microhabitats over 36 years

Long-term genetic studies of wild populations are very scarce, but are essential for connecting ecological and population genetics models, and for understanding the dynamics of biodiversity. We present a study of a wild wheat population sampled over a 36-year period at high spatial resolution. We genotyped 832 individuals from regular sampling along transects during the course of the experiment. Genotypes were clustered into ecological microhabitats over scales of tens of metres, and this clustering was remarkably stable over the 36 generations of the study. Simulations show that it is difficult to explain this spatial and temporal stability using only limited dispersal, suggesting a role for fine-scale local adaptation to ecological parameters. Using a common-garden experiment, we showed that the genotypes found in distinct microhabitats differ phenotypically, further supporting the hypothesis of local adaptation. Our results provide a rare insight into the population genetics of a natural population over a long monitoring period.

evolutionary biology↗

bioRxiv2021

Genome sequences of Aegilops species of section Sitopsis reveal phylogenetic relationships and provide resources for wheat improvement

Aegilops is a close relative of wheat (Triticum spp.), and Aegilops species in the section Sitopsis represent a rich reservoir of genetic diversity for improvement of wheat. To understand their diversity and advance their utilization, we produced whole-genome assemblies of Ae. longissima and Ae. speltoides. Whole-genome comparative analysis, along with the recently sequenced Ae. sharonensis genome, showed that the Ae. longissima and Ae. sharonensis genomes are highly similar and most closely related to the wheat D subgenome. By contrast, the Ae. speltoides genome is more closely related to the B subgenome. Haplotype block analysis supported the idea that Ae. speltoides is the closest ancestor of the wheat B subgenome and highlighted variable and similar genomic regions between the three Aegilops species and wheat. Genome-wide analysis of nucleotide-binding site leucine-rich repeat (NLR) genes revealed species-specific and lineage-specific NLR genes and variants, demonstrating the potential of Aegilops genomes for wheat improvement. TeaserGenome sequences of Aegilops species provides a key for efficient exploitation of this rich genetic resource in wheat improvement.

plant biology↗