We sequenced the entire tb1 gene in six maize inbreds and its wild relatives (parviglumis, mexicana, perennis and luxurians) to characterize it at molecular level. Hopscotch and Tourist transposable elements were observed in the upstream of tb1 in all maize inbreds, while they were absent in wild relatives. In maize, tb1 consisted of 431–443 bp 5′UTR, 1101 bp coding sequence and 211–219 bp 3′UTR. In promoter region, mutations in the light response element in mexicana (~ 35 bp and ~ 55 bp upstream of TSS) and perennis (at ~ 35 bp upstream of TSS) were found. A 6 bp insertion at 420 bp downstream of the polyA signal site was present among teosinte accessions, while it was not observed in maize. A codominant marker flanking the 6 bp InDel was developed, and it differentiated the teosintes from maize. In Tb1 protein, alanine (12.7–14.6%) was the most abundant amino acid with tryptophan as the rarest (0.5–0.9%). The molecular weight of Tb1 protein was 38757.15 g/mol except ‘Palomero Toluqueno’ and HKI1128. R and TCP motifs in Tb1 protein were highly conserved across maize, teosinte and orthologues, while TCP domain differed for tb1 paralogue. Tb1 possessed important role in light-, auxin-, stress-response and meristem identity maintenance. Presence of molecular signal suggested its localization in mitochondria, nucleus and nucleolus. Parviglumis and mexicana shared closer relationship with maize than perennis and luxurians. A highly conserved 59–60 amino acids long bHLH region was observed across genotypes. Information generated here assumes significance in evolution of tb1 gene and breeding for enhancement of prolificacy in maize.

Maize is an important food, feed, fodder and industrial crop in addition to being a valuable source of micronutrients. Phytic acid (PA), an anti-nutritional factor in maize, makes crucial minerals inaccessible to monogastric animals. The low phytic acid-1 (lpa1) gene located on chromosome-1S is 7292 bp long with 11 exons, and the recessive lpa1-1 allele reduces the accumulation of PA thereby enhances the bioavailability of essential minerals in maize kernels. Here, we characterized the full-length Lpa1 gene sequence in three mutants (lpa1-1) and seven wild-type (Lpa1) maize inbreds. Sequence analysis revealed 607 polymorphic sites across Lpa1 sequences, indicating wide variability for Lpa1 among the inbreds. Further, SNP from “C” to “T” differentiated wild-type and mutant-type alleles at 1432 amino acid position. Gene-based diversity among 48 diverse maize inbreds using 15 InDel markers revealed the formation of 42 distinct haplotypes; six of which (Hap6, Hap16, Hap17, Hap19 Hap27 and Hap31) were shared by more than one genotype. The number of exons in Lpa1 ranged from 11–19 among maize genotypes and 6–14 among 26 orthologues. Major functional motifs of Lpa1 detected were ATP-binding Cassette (ABC) transporter trans-membrane region and ABC transporter. Phylogenetic tree using nucleotide and protein sequences revealed a closer relationship of maize Lpa1 sequences with Sorghum bicolor, Panicum hallii, Setaria italica and S. viridis. This study offered newer insights into the understanding of the genetic diversity of the Lpa1 gene in maize and related crop-species, and information generated here would further help in exploiting the lpa1 mutant for the enhancement of nutritional value in maize kernels.