Structure, expression profile and phylogenetic inference of chalcone isomerase-like genes from the narrow-leafed lupin (Lupinus angustifolius L.) genome

Abstract

Lupins, like other legumes, have a unique biosynthesis scheme of 5-deoxy-type flavonoids and isoflavonoids. A key enzyme in this pathway is chalcone isomerase (CHI), a member of CHI-fold protein family, encompassing subfamilies of CHI1, CHI2, CHI-like (CHIL), and fatty acid-binding (FAP) proteins. Here, two Lupinus angustifolius (narrow-leafed lupin) CHILs, LangCHIL1 and LangCHIL2, were identified and characterized using DNA fingerprinting, cytogenetic and linkage mapping, sequencing and expression profiling. Clones carrying CHIL sequences were assembled into two contigs. Full gene sequences were obtained from these contigs, and mapped in two L. angustifolius linkage groups by gene-specific markers. Bacterial artificial chromosome fluorescence in situ hybridization approach confirmed the localization of two LangCHIL genes in distinct chromosomes. The expression profiles of both LangCHIL isoforms were very similar. The highest level of transcription was in the roots of the third week of plant growth; thereafter, expression declined. The expression of both LangCHIL genes in leaves and stems was similar and low. Comparative mapping to reference legume genome sequences revealed strong syntenic links; however, LangCHIL2 contig had a much more conserved structure than LangCHIL1. LangCHIL2 is assumed to be an ancestor gene, whereas LangCHIL1 probably appeared as a result of duplication. As both copies are transcriptionally active, questions arise concerning their hypothetical functional divergence. Screening of the narrow-leafed lupin genome and transcriptome with CHI-fold protein sequences, followed by Bayesian inference of phylogeny and cross-genera synteny survey, identified representatives of all but one (CHI1) main subfamilies. They are as follows: two copies of CHI2, FAPa2 and CHIL, and single copies of FAPb and FAPa1. Duplicated genes are remnants of whole genome duplication which is assumed to have occurred after the divergence of Lupinus, Arachis, and Glycine.

Validation of Diaporthe toxica resistance markers in European Lupinus angustifolius germplasm and identification of novel resistance donors for marker-assisted selection

“…Highdensity linkage maps carrying thousands of markers, including gene-based sequence tagged sites (STS), were constructed and aligned to the draft genome sequence (Hane et al 2017;Kamphuis et al 2015;Nelson et al 2006;Yang et al 2013b). Exploitation of BAC resources for cytogenetic mapping resulted in the integration of all linkage groups with the corresponding chromosomes, as well as in the identification of several gene-rich regions (Książkiewicz et al 2013(Książkiewicz et al , 2015Leśniewska et al 2011;Przysiecka et al 2015;Wyrwa et al 2016). The release of reference transcriptomes for wild and domesticated lupin accessions constituted a platform for targeting particular genes of interest (Kamphuis et al 2015).…”

Identifying Stable Reference Genes for qRT-PCR Normalisation in Gene Expression Studies of Narrow-Leafed Lupin (Lupinus angustifolius L.)

“…As a result, transcriptome and gene expression studies of narrow-leafed lupin (such as that of Przysiecka et al . [ 27 ]) are likely to increase in number and be of great future value.…”

A Tale of Two Families: Whole Genome and Segmental Duplications Underlie Glutamine Synthetase and Phosphoenolpyruvate Carboxylase Diversity in Narrow-Leafed Lupin (Lupinus angustifolius L.)

“…During the early divergence of some downstream lineages, dated to roughly~30-55 mya, additional independent WGD events probably occurred, affecting Mimosoideae-Cassiinae-Caesalpinieae, Detarieae, Cercideae, and Lupinus clades [75]. Large-scale duplication and/or triplication in the L. angustifolius genome has been well-evidenced by recent studies involving linkage and comparative mapping [17,36] and microsynteny analysis of selected gene families [30,31,34,62,63]. These WGD events apparently contributed to multiplication of the gene copy number of L. angustifolius GS and PEPC genes because hypothetical duplicates were found in sister branches of the phylogenetic tree and the genome regions harboring these genes shared common collinearity links.…”

“…Hane et al estimated the Papilionoideae radiation at 58 mya with genistoid lineage separation from the other Papilionoideae legumes at 54.6 mya, followed by whole-genome triplication in the genistoid lineage at 24.6 mya [11]. Additionally, the ancient polyploidy event has been confirmed based on an analysis of several genes, such as chalcone isomerases (CHI) [62], phosphatidylethanolamine binding proteins (PEBP) [30], isoflavone synthetases (IFS) [63], and cytosolic and plastid acetyl-coenzyme A carboxylases (ACCase) [64]. All listed genes are present in the narrow-leafed lupin genome in multiple variants and evolved by WGDs, evidenced by shared synteny and Bayesian phylogenetic inference.…”