ABSTRACT Advancements in plant genome sequencing and assembly have enabled the production of increasingly accurate and contiguous genome sequences. Here, we present the chromosome‐level assembly of the durum wheat ( Triticum turgidum L. ssp. durum, cv. Svevo) reference genome produced using accurate long‐reads, optical mapping and Hi‐C. The new assembly (Svevo Rel.2.0) comprises 263 hybrid scaffolds with an N50 value of 112.3 Mb, arranged into 14 contiguous pseudomolecules spanning 10.4 Gb. The Svevo Rel.2.0 genome assembly was annotated using extensive short‐ and long‐read RNA sequencing data obtained from 60 tissue/treatment combinations. The resulting annotation comprises 68 154 high‐confidence protein‐coding genes, which have been integrated into a comprehensive transcriptome atlas accessible through an eFP browser. Annotation was manually curated for storage protein gene families and for Leucine‐Rich Repeat‐Containing Receptor genes yielding 3763 LRR‐CR loci. The genome assembly's accuracy and completeness were demonstrated by the correct reconstruction of the physical map of Tg1‐B (Tenacious glumes 1), a locus controlling the free threshing trait located on chromosome 2B that was not assembled in the previous genome release (Svevo Rel.1.0). A wealth of 6621 QTLs/MTAs from the literature were mapped onto Svevo Rel.2.0 to identify QTL hotspots and trait‐specific candidate genes. The ancestry of the durum genome to representative wild emmer populations from North‐Eastern and Southern‐Levant Fertile Crescent assessed by tracing haplotype transmission patterns revealed a clear mosaic pattern. This new durum reference genome, enhanced with advanced annotation and an expression atlas linked to QTLome data, is the most comprehensive tool available for durum wheat genomics.
E. Mazzucotelli, C. Forestan, Gina Zastrow-Hayes et al.· Plant Biotechnology Journal· 0 citations
Bread wheat (Triticum aestivum L.) is a major staple crop providing essential calories for human diets. However, intensive breeding for yield has reduced genetic diversity for quality traits, including grain protein content (GPC). Induced mutagenesis offers an effective strategy to broaden the genetic base and generate novel alleles affecting agronomic traits. In this study, M₅ mutant lines of the spring wheat cultivar Eritrospermum-35 were developed through gamma irradiation at 100 Gy and 200 Gy. Lines were evaluated for variation in GPC and days from sowing to heading under controlled greenhouse conditions. GPC was measured using near-infrared reflectance spectroscopy (NIR), and allelic variation at the candidate gene Eps-Am1 was analyzed using PCR-based markers. Substantial variation in GPC was observed. The 100 Gy lines showed GPC values ranging from 12.60% to 14.43% (mean 13.56 ± 0.57%), whereas the 200 Gy lines had a mean GPC of 13.76 ± 0.63%. Eleven mutant lines (37%) exhibited significantly higher GPC (5.7–11.0%) than the parent. Importantly, the increase in GPC was not associated with a reduction in thousand kernel weight; TKW values were higher in irradiated lines compared with the parent. Days to heading differed between treatments: 100 Gy lines headed earlier, while 200 Gy lines showed delayed heading. Molecular screening identified new alleles of Eps-Am1, with allele carriers generally exhibiting earlier heading. Overall, gamma irradiation generated valuable genetic variation for improving grain protein content and adaptive traits in spring wheat.
Key words: gamma irradiation, grain protein content, days to heading, thousand kernel weight, spring wheat, Eps-Am1, mutation breeding.
G. Doktyrbay, S. Kenzhebayeva, S. Atabayeva et al.· International Journal of Bio...· 0 citations
