Genome-Wide Identification, Evolutionary and Expression Analyses of the GALACTINOL SYNTHASE Gene Family in Rapeseed and Tobacco

Abstract

Galactinol synthase (GolS) is a key enzyme in raffinose family oligosaccharide (RFO) biosynthesis. The finding that GolS accumulates in plants exposed to abiotic stresses indicates RFOs function in environmental adaptation. However, the evolutionary relationships and biological functions of GolS family in rapeseed (Brassica napus) and tobacco (Nicotiana tabacum) remain unclear. In this study, we identified 20 BnGolS and 9 NtGolS genes. Subcellular localization predictions showed that most of the proteins are localized to the cytoplasm. Phylogenetic analysis identified a lost event of an ancient GolS copy in the Solanaceae and an ancient duplication event leading to evolution of GolS4/7 in the Brassicaceae. The three-dimensional structures of two GolS proteins were conserved, with an important DxD motif for binding to UDP-galactose (uridine diphosphate-galactose) and inositol. Expression profile analysis indicated that BnGolS and NtGolS genes were expressed in most tissues and highly expressed in one or two specific tissues. Hormone treatments strongly induced the expression of most BnGolS genes and homologous genes in the same subfamilies exhibited divergent-induced expression. Our study provides a comprehensive evolutionary analysis of GolS genes among the Brassicaceae and Solanaceae as well as an insight into the biological function of GolS genes in hormone response in plants.

Biochemical characterization of recombinant UDP-sugar pyrophosphorylase and galactinol synthase fromBrachypodium distachyon

“…A close inspection of the protein sequence showed high conservation of motifs found in enzymes from the GT8 family, including the DxD, HxxGxxKPW, GLG, NAG, and FLAG domains (Supplemental File S1), also described in previous publications (Sengupta et al, 2012;Salvi et al, 2016;Fan et al, 2017). Most of these regions are buried inside the protein, forming the putative catalytic pocket (Fig.…”

“…The subfunctionalization of GolSases (Rastogi and Liberles, 2005), not only in B. distachyon but also in other plant species (Fig. 2), might allow plants tolerate different abiotic stress conditions (Fan et al, 2017). As previously mentioned, different GolSase genes are expressed in A. thaliana plants exposed to drought, heat, and high salinity (AtGolS1 and AtGolS2) or cold (AtGolS3; Taji et al, 2002).…”

Genome-Wide Identification and Characterization of NODULE-INCEPTION-Like Protein (NLP) Family Genes in Brassica napus

“…To identify NLP genes in these species, nine NLP protein sequences from Arabidopsis were used as queries in a reciprocal Basic Local Alignment Search Tool Protein (BLASTP) analysis [44,45] using the threshold and minimum alignment coverage parameters described previously [46]. All NLP protein sequences were further analyzed using PfamScan () to confirm the presence of two NLP-related domains, RWP-RK (PF02042) and PBl (PF00564), with an e -value cut-off of 1 × 10 −5 .…”

Genome-Wide Identification of Flowering-Time Genes in Brassica Species and Reveals a Correlation between Selective Pressure and Expression Patterns of Vernalization-Pathway Genes in Brassica napus

“…For domain-containing genes, their Hidden Markov Model (HMM) profiles were acquired from the HMMER web server ( ) and used as queries to search against all the Brassica protein sequences using the HMMER V3.0 program (Ashburn, VA, USA) (version 3.1b2, [ 62 ]) to identify candidate genes containing the corresponding functional domains, with an E-value of more than the default “inclusion threshold” as the threshold. To accurately identify flowering-time domain-containing genes in the three Brassica species, all the filtered candidate genes were then used as queries using the Basic Local Alignment Search Tool Protein (BLASTP) program (Bethesda, MD, USA) ([ 63 ]) to search against the A. thaliana proteome database to investigate their corresponding orthologs, with a threshold E-value of 1e-5 and a minimum alignment coverage of 50% [ 64 ].…”