The causal mutation leading to sweetness in modern white lupin cultivars

Abstract

Lupins are high-protein crops that are rapidly gaining interest as hardy alternatives to soybean; however, they accumulate antinutritional alkaloids of the quinolizidine type (QAs). Lupin domestication was enabled by the discovery of genetic loci conferring low QA levels (sweetness), but the precise identity of the underlying genes remains uncertain. We show that pauper , the most common sweet locus in white lupin, encodes an acetyltransferase (AT) unexpectedly involved in the early QA pathway. In pauper plants, a single-nucleotide polymorphism (SNP) strongly impairs AT activity, causing pathway blockage. We corroborate our hypothesis by replicating the pauper chemotype in narrow-leafed lupin via mutagenesis. Our work adds a new dimension to QA biosynthesis and establishes the identity of a lupin sweet gene for the first time, thus facilitating lupin breeding and enabling domestication of other QA-containing legumes.

Nonsymmetric formation of Δ1-piperideine from lysine in plants via a bacterial-like PLP-dependent enzyme

“…∆ 1 -Piperideine is not stable as it is prone to spontaneous isomerisation, dimerisation, trimerisation and higher oligomerisation, equilibrating in solution, with the dominant form in solution being dependent on the solvent and pH 29 . This behaviour may contribute to its biosynthetic role in some alkaloid pathways, such as that recently described in lupin alkaloid biosynthesis 11 . However, these properties can make analysis challenging, hence why we detect it at the dimer mass ([2M+H] + = 167), and why the peak shape is not typically Gaussian.…”

“…1A). The biosynthesis of these piperidine alkaloids has been under intensive investigation, with the aim of discovering the pathway enzymes to allow either formation of alkaloids in heterologous systems 9,10 or the elimination of alkaloid biosynthesis in host tissues 7,11 .…”

Metabolic engineering of narrow-leafed lupin for the production of enantiomerically pure (‒)-sparteine

“…Motivated by the prospect of generating a (−)-sparteine-accumulating NLL plant, we isolated a CYP71D189 knockout from our recently constructed, non-GMO NLL mutant library 31 (Suppl. Fig.…”