Kappaphycus alvarezii sap mitigates abiotic-induced stress in Triticum durum by modulating metabolic coordination and improves growth and yield

摘要

Kappaphycus alvarezii sap (K-sap) facilitates plant growth in stressful environments by regulating the stress signalling components of the plant system. In the present study, the effect of K-sap on three durum wheat varieties, commercially important for pasta and semolina is studied in response to salt and drought stress during both vegetative and reproductive growth phases. The application of K-sap contributed to the improvement of the morphological, physio-biochemical parameters and gene expression facilitating improved growth and yield. Under salt stress, K-sap-treated plants maintained lower Na+/K+ ratio and higher Ca2+ content. During stress, K-sap reduced cell membrane damage by maintaining higher tissue water content, reduced electrolyte leakage and reduced malondialdehyde contents. Reactive oxygen species, superoxide and peroxide contents were also significantly reduced on K-sap treatment. Osmoprotectants such as total proteins, proline, amino acids and soluble sugars increased with K-sap application both with and without stress. The phytohormones abscisic acid, cytokinin and auxin were significantly regulated by K-sap application. qPCR analysis showed enhanced expression of stress-responsive wheat MAP kinase, WRKY transcription factor and antioxidative genes with K-sap treatment during stress. The application of K-sap significantly improved yield by increasing number of spikes and grains. Here, we report for the first time the integrative study of metabolic components coordinated by genes and hormones to reveal the mechanism of K-sap in durum wheat for improving yield and stress tolerance.