Genome-wide Identification and In silico Analysis of Fatty Acid Desaturase (FAD) Genes of Pearl Millet (Pennisetum glaucum L.)

Abstract

Aim: The present study focused on a comprehensive in silico investigation to identify and characterize the fatty acid desaturase gene family in Pennisetum glaucum L. (pearl millet). Fatty Acid Desaturases (FADs) are essential enzymes in plants that introduce double bonds into fatty acid chains and play a key role in the producing unsaturated fatty acids. These key enzymes identified and characterized through the Kennedy pathway play a major role in fatty acid metabolism. They significantly contribute to plant membrane fluidity, stress tolerance and oil quality. Methodology: To identify the FAD gene family NovoGene Millet database was used; their gene, promoter, complementary DNA (cDNA) and the corresponding amino acid sequences were retrieved from the database. Chromosomal distribution was predicted through mapping tools in the millet database, and synteny maps were developed through MCscanX option in the TB-tools. Gene Structure Display Server 2.0 software was used to predict gene structures, and the PlantCARE database was employed to identify the cis-regulatory elements in the putative promoter sequences of respective FAD genes. Results: A total of 22 PgFAD genes were identified and mapped across seven chromosomes of pearl millet, indicating their uneven distribution and suggesting potential duplication events. The gene structure of PgFADs was represented by various introns and exons. Cis-regulatory element analysis of 1 kb upstream promoter regions of all PgFADs highlighted the presence of various stress and phytohormone-responsive elements like STRE, WRE3, ABRE, MYB, ERE and WUN motifs indicating the potential involvement of PgFAD genes in stress and developmental regulation in plants. Synteny analysis with different cereal species such as rice (Oryza sativa), foxtail millet (Setaria italica), finger millet (Eleusine coracana), maize (Zea mays) and sorghum (Sorghum bicolor) revealed conserved evolutionary relationships and potential gene duplication events. Conclusion: This study provides valuable insights into the molecular characteristics and evolutionary relationships of FAD genes in pearl millet and lays the foundation for future functional studies and crop improvement strategies that target fatty acid metabolism.