Comparative Investigation of Glutathione S-transferase (GST) in Different Crops and Purification of High Active GSTs from Onion (Allium cepa L.)

Abstract

Glutathione S-transferases (GSTs; EC 2.5.1.18) are abundant proteins encoded by a highly divergent ancient gene family with protective functions through detoxification and non-catalytic roles as carriers of cytotoxins. In this work, we investigated the GST activities in seedlings of 38 crops to obtain a plant with high active GST for further study. In screening of 38 crops, onion seedling showed the highest GST activity (483.54 nmol min -1 mg -1 protein) followed by wheat(372.89 nmol min -1 mg -1 protein), barley (253.44 nmol min -1 mg -1 protein), rice (244.12 nmol min -1 mg -1 protein) and proso millet (173.34 nmol min -1 mg -1 protein). Carrot seedling showed the lowest activity (3.63 nmol min -1 mg -1 protein).In onion plants, both root and leaf showed high GST activity. Onion bulb GSTs were separated DEAE cellulose column chromatography, and purified by affinity chromatography (S-hexyl glutathione-agarose). Three GST peaks were found to elute at 67, 107 and 140mM of KCl gradient solution, and were named as GSTa, GSTb and GSTc. Among the three GSTs, GSTa, GSTb and GSTc contained 9.58, 61.45 and 28.97% of total activity, respectively. In purification, GSTa, GSTb and GSTc had specific activities of 9075, 17259 and 19868 nmol min -1 mg -1 protein, respectively, along with yield of 2.48, 3.17 and 1.28,and purification fold of 15.8, 29.9 and 34.5, respectively. The purity and molecular mass of the fraction was examined by SDS-PAGE. The silver staining of the purified GSTa, GSTb and GSTc indicated that final product of GSTb and GSTc were highly purified and migrated as a single band on SDS-PAGE with an apparent molecular mass of 27 kDa. However, GSTa eluted with Glyoxalase-I (Gly-I) and to purify GSTa, more methodological application are suggested.

Transcriptome Analysis Reveals the Response Mechanism of Digitaria sanguinalis, Arabidopsis thaliana and Poa annua under 4,8-Dihydroxy-1-tetralone Treatment

“…Other studies on stress have also found that genes responsible for antioxidants show varying patterns of expression in response to abiotic stressors. OsGPXs are increased in response to drought and oxidative stress, whereas they are downregulated in response to salt, heat, and cold [ 48 ]. It is speculated that this may be due to the abnormal sensitivity of Digitaria sanguinalis to 4,8-DHT, which produces significant quantities of ROS, leading to the inactivation of antioxidant enzymes or its components, exacerbating plant damage.…”

Salinity and drought-induced methylglyoxal detoxification in Brassica spp. and purification of a high active glyoxalase I from tolerant genotype

“…Glyoxalase I assay was carried out according to the method of Islam et al (2015) with slight modification. Briefly, the assay mixture contained 100mM sodium phosphate buffer (pH 7.5), 15 mM magnesium sulphate, 1.7 mM glutathione and 3.5 mM MG.…”