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

This experiment was conducted to study the role of glyoxalase system in conferring salinity and drought stress in Brassica spp. Two Brassica genotypes viz. BARI Sharisha16 (tolerant) and Tori7 (susceptible) were exposed to salt (16 dS m) and drought for 2, 4 and 6 days. The comparative study of two Brassica genotypes under salinity and drought stresses revealed that BARI Sharisha16 is more tolerant than Tori7 in both stresses. Under drought stress and salinity stress, Gly I activity increased significantly in both genotypes. Notably, concomitant increased activities of Gly I and Gly II with increased methylglyoxal (MG) suggested their role in MG detoxification in Brassica Spp. At six-day of salt stress, it was remarkable that Gly I and Gly II activities were 49 and 36 % higher in BARI Sharisha16 than Tori7. In addition, Gly I and Gly II activities were 24 and 21 % higher in BARI Sharisha16 than Tori7 after sixth day of drought, and hence, using different column chromatography Gly I was purified from BARI Sharisha16 seedlings. In purification, the fraction eluted from affinity chromatography showed specific activity of 173.51 μM minmg protein. In SDSPAGE, the purified Gly I protein migrated as a single band on with an apparent molecular mass of 27 kDa. In final purification, the recovery of Gly I activity was 0.38% along with purification fold 112.7. In this study, role of glyoxalase system in detoxification of MG was observed and subsequently, Gly I was purified from tolerant genotypes.