A Bitter-Sweet Story: Unraveling the Genes Involved in Quinolizidine Alkaloid Synthesis in Lupinus albus

Abstract

Alkaloids are part of a structurally diverse group of over 21,000 cyclic nitrogen-containing secondary metabolites that are found in over 20% of plant species. Lupinus albus are naturally containing quinolizidine alkaloid (QA) legumes, with wild accessions containing up to 11% of QA in seeds. Notwithstanding their clear advantages as a natural protecting system, lupin-breeding programs have selected against QA content without proper understanding of quinolizidine alkaloid biosynthetic pathway. This review summarizes the current status in this field, with focus on the utilization of natural mutations such as the one contained in pauper locus, and more recently the development of molecular markers, which along with the advent of sequencing technology, have facilitated the identification of candidate genes located in the pauper region. New insights for future research are provided, including the utilization of differentially expressed genes located on the pauper locus, as candidates for genome editing. Identification of the main genes involved in the biosynthesis of QA will enable precision breeding of low-alkaloid, high nutrition white lupin. This is important as plant based high quality protein for food and feed is an essential for sustainable agricultural productivity.

Biosynthesis of quinolizidine alkaloids in lupins: mechanistic considerations and prospects for pathway elucidation

“…In lupin breeding, several different loci are known to control QA levels in L. angustifolius, L. albus, L. luteus and L. mutabilis; however, the identity of the underlying genes remains unknown. 72 Candidate genes have been proposed for the iucundus [73][74][75] and pauper 76,77 loci, but further work is needed to pinpoint single genes and establish causality. Similarly, mutagenized populations in a high-QA background may yield several low-QA mutant phenotypes, and the causative mutations can be identied in forward genetics approaches.…”

Impact of ultrasound processing on alternative protein systems: Protein extraction, nutritional effects and associated challenges

“…The toxic secondary plant metabolite, quinolizidine alkaloid (QA) in lupin seed proteins, is known for displaying both teratogenic and anti-cholinergic effects [127] . Aguilar-Acosta, Serna-Saldivar [128] determined low levels of lupanine (30 mg /100 g protein isolate) when extracting protein from Lupin mutabilis using UAE (US probe, 24 kHz, 100 % amplitude (100 μm), 85 W/cm 2 for 15 min).…”

Isoflavone Content and Nutritional-Related Properties of Debittered Seeds from Two Andean Lupin (Lupinus mutabilis Sweet) Ecotypes Propagated in Two Soils

“…Therefore, these investigated ecotypes suit lupin protein sources cultivated in both soils. However, the results of L. mutabilis raw seed characterization revealed that LC and LP ecotypes have an appreciable alkaloid content that must be removed before further analysis since these compounds have anti-nutritional properties [56]. Alkaloids have been previously reported in L. mutabilis seeds from plants collected in Ecuador [30] or Peru [57,58].…”