Abiotic stresses alter expression of S-Adenosylmethionine synthetase gene, polyamines and antioxidant activity in pigeon pea (Cajanus cajan L.)

Expression of S-Adenosylmethionine synthetase (SAMS) gene in pigeon pea (Cajanus cajan L.) was analyzed by qRT PCR during abiotic stresses viz., drought, heavy metal (CdCl₂) and cold. Maximum expression of SAMSgene in the leaves were observed at 3 days after drought stress with 15% PEG. Conversely, its expression was not detected in leaves and roots at cadmium stress but transcripts were down regulated as compared to the control. After 6 days of stress expression of SAMS gene was increased in leaves and roots as compared to the control but it was lower than its expression at 3 days after stress. The activities of antioxidative enzymes like glutathione reductase, glutathione-s-transferase, ascorbate peroxidase and metabolite constituents like polyamines and glycine betaine were also analyzed. The activities of antioxidative enzymes and concentration of glycine betaine showed remarkable increase in response to all stresses, except ascorbate peroxidase in heavy metal stress.