磺胺类抗生素对玉米幼苗生长、生理及代谢组的影响

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

【目的】研究典型磺胺类抗生素(Sulfonamides,SAs)对玉米幼苗生长、生理及代谢组的影响,为进一步探究玉米对SAs的响应机制提供理论依据。【方法】以玉米品种郑单958和掖单13为试验材料,以不添加SAs为对照(0 mg/L),以终浓度为10、20、30、40和50 mg/L的磺胺甲基嘧啶(SM1)和磺胺二甲基嘧啶(SM2)为处理,测定分析对照及不同处理玉米幼苗的生长和生理指标,并通过气相色谱—质谱联用仪(GC-MS)对玉米幼苗代谢物的含量及种类进行检测。【结果】2种SAs处理后,玉米幼苗的根长、株高、鲜重、干重和叶绿素含量总体上表现出低促高抑的变化趋势。超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性被激活,总体变化趋势为先上升后下降。经GC-MS检测出代谢物共70种,主要为有机酸、氨基酸、糖类及其衍生物和其他代谢物,将筛选到的12种差异代谢物富集到代谢通路上,结果映射得出7条显著的代谢路径:氨酰基-tRNA的生物合成,氰氨基酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,缬氨酸、亮氨酸和异亮氨酸的生物合成,乙醛酸和二羧酸的代谢,甘氨酸、丝氨酸和苏氨酸代谢,异喹啉生物碱的生物合成。【结论】SAs对玉米幼苗生长和生理指标的影响呈低促高抑的效果。高浓度SAs使玉米幼苗生长受抑,光合色素含量降低,遭受氧化损伤,具有不可忽视的生态毒性。氨基酸类代谢物为玉米幼苗响应SAs的关键代谢物。郑单958对SAs的耐性比掖单13强。

【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 explo-ring 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 indi-cators 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 ac-tivated,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 seed-lings,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.