Metabolite profiles of ‘khao dawk mali 105’ and salt-tolerant ‘UBN 02123-50R-B-2’ rice oryza sativa L. under menadione-induced oxidative stress

Abstract

The responses of plants under various environmental stresses, including biotic and abiotic stresses, eventually lead to oxidative stress condition. Gene regulations and metabolic changes are important for cellular activity adaptation. To understand these changes, menadione application was used to induce oxidative stress in two cultivars, salt-sensitive Khao Dawk Mali (KDML) 105 and salt-tolerant 'UBN 02123-50R-B-2' (UBN), of five-day-old rice (Oryza sativa L.) seedlings for 0.5, 2, and 6 hours. The assessment of oxidative stress by aconitase activity assay indicated that UBN is able to endure the stress better than KDML 105. Major changes of both cultivars under the stress were a reduction of inorganic contents and primary metabolites. Comparison of cultivar-dependent influences suggests a higher basal metabolite level in UBN, 4-amino-butanoic acid and asparagine. In addition, UBN under the stress condition showed an increment in a variety of glycosylflavones. Higher nitrogen assimilation processes probably provide a better stress tolerance in UBN. Due to the importance of sulfate assimilation under oxidative stress, quantitative RT-PCR analysis was performed and higher up-regulations of sulfate transporter and sulfate-responsive genes in UBN were found. Therefore, these results provide evidences supporting a superior stress tolerance capability of UBN over KDML 105.