BABA priming reinforces chitosan nanoparticle-induced reprogramming of carbon–nitrogen and phenylpropanoid metabolism in Cyamopsis tetragonoloba L

To meet global demand for high-quality raw materials, improving the industrial and nutritional value of crops like guar (Cyamopsis tetragonoloba L.) is essential. This research demonstrates that β-aminobutyric acid (BABA) acts as a potent priming agent that synergistically reinforces chitosan nanoparticle (CNP)-induced metabolic shifts in guar. BABA-priming further improved the positive effect of CNPs on yield, metabolism and mineral acquisition (30-57%). This reinforcement was most evident in improved primary metabolism, particularly elevated sugar, amino acid, and fatty acid levels. The induced lipid metabolism resulted in a significant shift toward unsaturated fatty acids (+47-95%), substantially improving the seed's industrial and nutritional profile. Among amino acids, increased phenylalanine level fueled the phenylpropanoid pathway, where the combined treatment strongly stimulated key bioenzymatic activities (+85-233%) and substantially increased phenolic accumulation. This flux led to a 91% increase in lignin content and its biosynthetic enzymes, including phenylalanine ammonia-lyase (PAL), 4-coumarate:CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD), and caffeic acid O-methyltransferase (COMT). Multidimensional scaling confirmed that the BABA + CNP interaction redefines seed quality by redefining seed quality through coordinated improvements in mineral accumulation, fiber fractions, lipid composition, and secondary metabolites. Such enrichment also boosted the biological and industrial activity of the seeds, specifically their antimicrobial and antioxidant properties. These findings suggest that the BABA + CNP interaction provides a robust strategy for producing guar seeds with superior biological value and enhanced bioactive potential.