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Background: White lupin (Lupinus albus L.) is a high-protein Old World grain legume with remarkable food and feed production interest. It is sown in autumn or early spring, depending on the local agroclimatic conditions. This study aimed to identify allelic variants associated with vernalization responsiveness, in order to improve our knowledge of legume flowering regulatory pathways and develop molecular selection tools for the desired phenology as required for current breeding and adaptation to the changing climate. Results: Some 120 white lupin accessions originating from a wide range of environments of Europe, Africa, and Asia were phenotyped under field conditions in three environments with different intensities of vernalization, namely, a Mediterranean and a subcontinental climate sites of Italy under autumn sowing, and a suboceanic climate site of France under spring sowing. Two hundred sixty-two individual genotypes extracted from them were phenotyped in a greenhouse under long-day photoperiod without vernalization. Phenology data, and marker data generated by Diversity Arrays Technology sequencing (DArT-seq) and by PCR-based screening targeting published quantitative trait loci (QTLs) from linkage map and newly identified insertion/deletion polymorphisms in the promoter region of the FLOWERING LOCUS T homolog, LalbFTc1 gene (Lalb_Chr14g0364281), were subjected to a genome-wide association study (GWAS). Population structure followed differences in phenology and isolation by distance pattern. The GWAS highlighted numerous loci significantly associated with flowering time, including four LalbFTc1 gene promoter deletions: 2388 bp and 2126 bp deletions at the 5' end, a 264 bp deletion in the middle and a 28 bp deletion at the 3' end of the promoter. Besides LalbFTc1 deletions, this set contained DArT-seq markers that matched previously published major QTLs in chromosomes Lalb_Chr02, Lalb_Chr13 and Lalb_Chr16, and newly discovered QTLs in other chromosomes. Conclusions: This study highlighted novel QTLs for flowering time and validated those already published, thereby providing novel evidence on the convergence of FTc1 gene functional evolution into the vernalization pathway in Old World lupin species. Moreover, this research provided the set of loci specific for extreme phenotypes (the earliest or the latest) awaiting further implementation in marker-assisted selection for spring- or winter sowing. [ABSTRACT FROM AUTHOR]

Narrow-leafed lupin (Lupinus angustifolius L.) is a moderate-yielding legume crop known for its high grain protein content and contribution to soil improvement. It is cultivated under photoperiods ranging from 9 to 17 h, as a spring-sown (in colder locations) or as an autumn-sown crop (in warmer regions). Wild populations require a prolonged cold period, called vernalization, to induce flowering. The key achievement of L. angustifolius domestication was the discovery of two natural mutations (named Ku and Jul) conferring vernalization independence. These mutations are overlapping deletion variants in the promoter of LanFTc1 , a homolog of the Arabidopsis thaliana FLOWERING LOCUS T (FT) gene. The third deletion, named here as Pal , was recently found in primitive germplasm. In this study, we genotyped L. angustifolius germplasm that differs in domestication status and geographical origin for LanFTc1 alleles, which we then phenotyped to establish flowering time and vernalization responsiveness. The Ku and Jul lines were vernalization-independent and early flowering, wild (Ku) lines were vernalization-dependent and late flowering, whereas the Pal line conferred intermediate phenotype. Three lines representing Ku , Pal , and Ku alleles were subjected to gene expression surveys under 8- and 16-h photoperiods. FT homologs (LanFTa1 , LanFTa2 , LanFTc1 , and LanFTc2) and some genes selected by recent expression quantitative trait loci mapping were analyzed. Expression profiles of LanFTc1 and LanAGL8 (AGAMOUS-like 8) matched observed differences in flowering time between genotypes, highlighted by high induction after vernalization in the Ku line. Moreover, these genes revealed altered circadian clock control in Pal line under short days. LanFD (FD) and LanCRLK1 (CALCIUM/CALMODULIN-REGULATED RECEPTOR-LIKE KINASE 1) were negatively responsive to vernalization in Ku and Pal lines but positively responsive or variable in Ku , whereas LanUGT85A2 (UDP-GLUCOSYL TRANSFERASE 85A2) was significantly suppressed by vernalization in all lines. Such a pattern suggests the opposite regulation of these gene pairs in the vernalization pathway. LanCRLK1 and LanUGT85A2 are homologs of A. thaliana genes involved in the FLOWERING LOCUS C (FLC) vernalization pathway. Lupins, like many other legumes, do not have any FLC homologs. Therefore, candidate genes surveyed in this study, namely LanFTc1 , LanAGL8, LanCRLK1 , and LanUGT85A2 , may constitute anchors for further elucidation of molecular components contributing to vernalization response in legumes. [ABSTRACT FROM AUTHOR]

Genetic maps are an essential tool for investigating molecular markers' linkage with traits of agronomic importance. Breeders put a lot of emphasis on this type of markers, which are used in breeding programs implementation and speed up the process of a new variety development. In this paper, we construct a new, high-density linkage genetic map for Polish material on narrow-leafed lupin. The mapping population originated from crossing the Polish variety 'Emir' and the Belarusian breeding line 'LAE-1'. A new map was constructed based on DArTseq markers—a new type of marker generated with the next-generation sequencing (NGS) technique. The map was built with 4602 markers, which are divided into 20 linkage groups, corresponding with the number of gametic chromosomes in narrow-leafed lupin. On the new map there are 1174 unique loci. The total length of all linkage group is 3042 cM. This map was compared to the reference genome of narrow-leafed lupin and the CDS sequence for model legume species: emphMedicago truncatula, emphLotus japonicus and Glycine max. Analysis revealed the presence of the DArTseq marker common for all investigated species. We were able to map 38 new, unplaced scaffolds on the new genetic map of narrow-leafed lupin. The high-density genetic map we received can be used for quantitative trait locus (QTL) mapping, genome-wide association study analysis and assembly of the reference genome for the whole genome sequencing (WGS) method [ABSTRACT FROM AUTHOR]