Development of gene-based molecular markers tagging low alkaloid pauper locus in white lupin (Lupinus albus L.)

Sandra Rychel,Michał Książkiewicz

doi:10.1007/s13353-019-00508-9

Sandra Rychel, Michał Książkiewicz

Open Access

https://doi.org/10.1007/s13353-019-00508-9

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Abstract

White lupin (Lupinus albus L.) is a legume grain crop cultivated since ancient Greece and Egypt. Modern white lupin cultivars are appreciated as a source of protein with positive nutraceutical impact. However, white lupins produce anti-nutritional compounds, quinolizidine alkaloids, which provide bitter taste and have a negative influence on human health. During domestication of this species, several recessive alleles at unlinked loci controlling low alkaloid content were selected. One of these loci, pauper, was exploited worldwide providing numerous low-alkaloid cultivars. However, molecular tracking of pauper has been hampered due to the lack of diagnostic markers. In the present study, the synteny-based approach was harnessed to target pauper locus. Single-nucleotide polymorphisms flanking pauper locus on white lupin linkage map as well as candidate gene sequences elucidated from the narrow-leafed lupin (L. angustifolius L.) chromosome segment syntenic to the pauper linkage group region were transformed to PCR-based molecular markers. These markers were analyzed both in the mapping population and world germplasm collection. From fourteen markers screened, eleven were localized at a distance below 1.5 cM from this locus, including five co-segregating with pauper. The linkage of these markers was confirmed by high LOD values (up to 58.4). Validation performed in the set of 127 bitter and 23 sweet accessions evidenced high applicability of one marker, LAGI01_35805_F1_R1, for pauper locus selection, highlighted by the low ratio of false-positive scores (2.5%). LAGI01_35805 represents a homolog of L. angustifolius acyltransferase-like (LaAT) gene which might hypothetically participate in the alkaloid biosynthesis process in lupins.

Highlights

White lupin (Lupinus albus L.) is a cool season grain legume crop with a relatively long history of cultivation
Single-nucleotide polymorphisms flanking pauper locus on white lupin linkage map as well as candidate gene sequences elucidated from the narrow-leafed lupin (L. angustifolius L.) chromosome segment syntenic to the pauper linkage group region were transformed to PCR-based molecular markers
Molecular markers from the most recent L. albus linkage map localized in the proximity of the pauper locus were aligned to the L. angustifolius genome and gene sequences (Hane et al 2017) as well as to the L. albus transcriptome (O’Rourke et al 2013) to find anchors for primer design

Summary

Introduction

White lupin (Lupinus albus L.) is a cool season grain legume crop with a relatively long history of cultivation. As many as nine hypothetical loci controlling low alkaloid content were initially identified throughout white lupin breeding, including pauper, primus, tercius, exiguus, nutricius, mitis, suavis, reductus, and minutus (Hackbarth 1957; Hackbarth 1961; Porsche 1964; Šatović 1993; Troll 1958). Primus and tercius were identified as the synonyms of pauper, whereas suavis and minutus were not studied as extensively as the other loci and their independence cannot be authenticated (Harrison and Williams 1982). Three low-alkaloid alleles originating from different loci were introduced into white lupin cultivars in the early years of modern domestication, namely exiguus 1949); only a pauper was exploited worldwide (Harrison and Williams 1982; Šatović 1993)

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