Integrating computational and physiological analyses of galactomannan biosynthesis in Cyamopsis tetragonoloba

Cyamopsis tetragonoloba (guar or cluster bean) is an important arid legume valued for its medicinal properties and industrial gum production. The principal constituent of guar gum is galactomannan, a polysaccharide composed of galactose and mannose, synthesized in the seed endosperm through the galactomannan biosynthetic pathway. Despite its economic significance, little information is available on the structural and functional aspects of enzymes involved in this pathway. In the present study, key enzymes including α-D-galactoside galactohydrolase, β-1,4-mannan synthase (MS), phosphomannose isomerase (PMI), UDP-galactose 4-epimerase (UDP-G4E), and galactomannan galactosyltransferase (GGT) were characterized using bioinformatic approaches. Secondary and three-dimensional structures were predicted along with ligand-binding and active site identification. Physicochemical properties such as isoelectric point (pI), aliphatic index (AI), grand average of hydropathicity (GRAVY), instability index, hydrophobicity, and transmembrane activity were also analyzed, providing valuable insights into enzyme stability and functionality.To complement the computational analysis, guar plants were subjected to drought stress to examine physiological and gum-related responses. Relative water content, photosynthetic rate, and transpiration rate significantly decreased under water deficit, whereas anthocyanin content increased, suggesting enhanced antioxidant defense against reactive oxygen species (ROS). Pod yield was reduced under stress; however, seed gum yield and viscosity increased. Furthermore, expression of genes involved in galactomannan biosynthesis was upregulated under drought conditions, indicating a stress-induced shift towards enhanced gum accumulation.Overall, this multidisciplinary study integrates computational enzyme characterization with physiological and biochemical analyses, providing a comprehensive understanding of galactomannan biosynthesis and drought-induced gum modulation in C. tetragonoloba. These findings may facilitate targeted crop improvement strategies and industrial applications of guar gum under climate-stress scenarios.