Genomic organization and structural diversity of germin-like protein coding genes in foxtail millet (Setaria italica L.)

Germin-like protein (GLP) genes in plants constitute a multigene family that functions in a variety of biological processes, such as plant growth and development and respond to abiotic and biotic stresses. Available genome sequences of foxtail millet (Setaria italica) have facilitated the identification and delineation of the GLP gene family, which is perhaps the first report in any millet crop. A total of 20 SiGLP genes were mapped in six of the nine foxtail millet chromosomes. The majority of these SiGLP genes, except six, clustered into five known germin (GER) groups and revealed group-specific variations in their gene structure and conserved protein motifs. The SiGLP genes shared homologous relationship within and across plant genomes as per their syntenic chromosomal regions, indicating gene duplication and expansion in course of plant evolution. Gene expression dynamics revealed four out of the 20 SiGLP genes having a putative functional role in different tissues. The presence of diverse cis-acting regulatory elements in the putative SiGLP promoter sequences and homology-based 3-D protein structure predictions revealed their possible functional diversity. The present work encompasses a molecular insight into the organization and functions of SiGLP gene family members. This may serve as a platform for functional analysis and their efficient utilizations in genetic improvement of foxtail millet and other related crops.