Effects of sulfonamides on the growth,physiology and metabolome of maize seedlings

【Objective】 In this study, we explored the effects of typical sulfonamide antibiotics(Sulfonamides, SAs) on the growth, physiology and metabolome of maize seedlings, in order to provide a theoretical basis for further exploring the response mechanism of maize to SAs.【Method】 Two kinds of maize varieties(Zhengdan 958 and Yedan 13) were selected as the research materials with no added SAs as the control(0 mg/L), or with final concentrations of 10, 20, 30, 40 and 50 mg/L sulfamerazine(SM1) or sulfamethazine(SM2) as the treatments. The growth and physiological indicators of maize seedlings were determined and the types and contents of metabolites of maize seedlings were detected by gas chromatography-mass spectrometry(GC-MS).【Result】 After SAs treatment, the root length, plant height, fresh weight dry weight and chlorophyll of maize seedlings showed a trend that low concentration promoted but high concentration inhibited growth. The activities of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) enzymes were activated, and overall, the trend of change was firstly rising and then falling. A total of 70 metabolites were detected by GC-MS, mainly organic acids, amino acids, sugars and their derivatives and other metabolites. 12 different metabolites were obtained, which were enriched on the metabolic pathways, and 7 significant metabolic pathways were mapped out:aminoacyl-tRNA biosynthesis;cyanoamino acid metabolism;alanine, aspartate and glutamate metabolism;valine, leucine and isoleucine biosynthesis;glyoxylate and dicarboxylate metabolism;glycine, serine and threonine metabolism;isoquino-line alkaloid biosynthesis.【Conclusion】 For maize seedlings treated with SAs, they show the effect of being promoted at low concentrations but inhibited at high concentrations. The high concentration of SAs inhibits the growth of maize seedlings, reduces the photosynthetic pigment content, suffers oxidative damage, and has a non-negligible ecotoxicity. Amino acid metabolites are the key metabolites of maize seedlings in response to SAs stress. The resistance of Zhengdan 958 against SAs is stronger than Yedan 13.