ISOLATION, PURIFICATION AND PARTIAL CHARACTERIZATION OF LOW MOLECULAR WEIGHT PEPTIDES FROM NONPRIMED AND HALOPRIMED SEEDLINGS of Vigna mungo L. AND Cajanus cajan L. AND THEIR IMPACT ON PHYSIOLOGICAL ASPECTS UNDER NaCl EXPOSURE

Abstract

Plants confront an array of environmental stresses by tightly regulating their signalling pathways involving low molecular weight peptide synthesis. In the conducted study, initially growth parameters and ion contents were measured from salt stressed and haloprimed seedlings of blackgram (Vigna mungo L.) and pigeonpea (Cajanus cajan L.). Seedlings raised from nonprimed and haloprimed seeds were grown in hydroponic solution supplemented with desired concentration of NaCl for 3 weeks under controlled physiological conditions. Attempts were made to isolate low molecular weight peptide(s) from non-stressed, NaCl stressed and haloprimed seedlings of blackgram and pigeonpea, to quantify their variations and detect their molecular weight using HPLC and MALDI-TOF analysis respectively. Free radical scavenging activities of these peptides were studied under NaCl exposure. Subsequent bioassays were performed to determine the effect of these peptides on their respective physiological parameters. Peptide abundance was maximum in control seedlings of both the cultivars, which under NaCl stress became scanty. CD spectroscopic analysis confirmed reduced secondary conformations and more unordered peptides under NaCl stress. Haloprimed seedlings recovered such adversities to variable extents, resulting in improved germination and growth of test seedlings.