Isolation and bioinformatics characterization of horse gram (Macrotyloma uniflorum (Lam.) Verdc.) homologs (MuTFL1 and MuFLY) of genes controlling growth habit

Abstract

Growth habit (indeterminate/determinate) is one of the evolutionarily shaped, economically important plant architectural traits in grain legumes, including horse gram. Arabidopsis AtTFL1 and AtLFY genes and their homologs in other grain legume species are known to control growth habit. Taking cues from highly conserved domains in protein encoded by TFL1 and LFY genes, we isolated horse gram homologs (MuTFL1 and MuLFY) genes using reported degenerate primers designed to conserved domains. MuTFL1 and MuLFY homologs were isolated and sequenced using Sanger?s sequencing protocol. The nucleotide sequences of MuTFL1 and MuLFY homologs were translated to their corresponding amino acid sequences using ?ExPASy? tool. BLASTx analysis of the translated amino acid sequences of MuTFL1 and MuLFY homologs showed high similarity with those of soybean and pigeon pea TFL1 and LFY homologs. Multiple sequence alignment of nucleotide sequences of MuTFL1 and MuLFY with those of related legumes and model species (Medicago sp. and Lotus japonicas) using ?ClustalW? revealed the presence of four synonymous single nucleotide polymorphic (SNPs) sites in MuTFL1 and three non-synonymous SNP sites in MuLFY. These results suggest that not MuTFL1, but MuLFY could be the main regulator of growth habit in horse gram unlike in other non-model legumes where TFL1 was reported as the key gene controlling the growth habit. The substitution of glutamine in (determinate genotypes) with histidine (indeterminate genotypes) in LFY-coded protein appeared to be the cause for switch over from indeterminate to determinate growth habit in horse gram. These results are discussed in relation to strategies for breeding horse gram cultivars with desired growth habits.