Molecular characterization of dihydroneopterin aldolase and aminodeoxychorismate synthase in common bean—genes coding for enzymes in the folate synthesis pathway

Abstract

Common beans (Phaseolus vulgaris) are excellent sources of dietary folates, but different varieties contain different amounts of these compounds. Genes coding for dihydroneopterin aldolase (DHNA) and aminodeoxychorismate synthase (ADCS) of the folate synthesis pathway were characterized by PCR amplification, BAC clone sequencing, and whole genome sequencing. All DHNA and ADCS genes in the Mesoamerican cultivar OAC Rex were isolated and compared with those genes in the genome of Andean genotype G19833. Both genotypes have two functional DHNA genes and one pseudo gene. PvDHNA1 and PvDHNA2 proteins have similar secondary structures and conserved residues as DHNA homologs in Staphylococcus aureus and Arabidopsis. Sequence analysis and synteny mapping indicated that PvDHNA1 might be a duplicated and transposed copy of PvDHNA2. There is only one ADCS gene (PvADCS) identified in the bean genome and it is identical in OAC Rex and G19833. PvADCS has the conserved motifs required for catalytic activity similar to other plant ADCS homologs. DHNA and ADCS gene-specific markers were developed, mapped, and compared to their physical locations on chromosomes 1 and 7, respectively. The gene-specific markers developed in this study should be useful for detection and selection of varieties with enhanced folate contents in bean breeding programs.

Regulation of Plant Vitamin Metabolism: Backbone of Biofortification for the Alleviation of Hidden Hunger

“…Some candidate genes have been associated with the ratelimiting steps of vitB9, vitC, vitE, and carotenoid biosynthesis (Supplemental Figure 1). For example, vitamin accumulation was associated with the genes 7,8-DIHYDRONEOPTERIN ALDOLASE (DHNA) and ADCS in common beans (vitB9 biosynthesis; Xie et al, 2017), GGP in apple (vitC biosynthesis; Mellidou et al, 2012), MONODEHYDROASCORBATE REDU CTASE (MDHAR) in tomato (vitC recycling; Stevens et al, 2008), HOMOGENTISATE GERANYLGERANYLTRANSFERASE (HGGT), TOCOPHEROL CYCLASE (VTE1), HOMOGENTISATE PHYTYLTRANSFERASE (VTE2), g-TOCOPHEROL METHYL TRANSFERASE (VTE4), and GERANYLGERANYL DIPHOS PHATE SYNTHASE in barley (vitE biosynthesis; Graebner et al, 2015), and VTE1 and HGGT in maize (vitE biosynthesis; Lipka et al, 2013;Baseggio et al, 2019). In addition, one QTL in potato was found to be correlated with the synthesis of the vitB5 precursor b-alanine (Carreno-Quintero et al, 2012).…”