外源NO提高玉米瘤黑粉病抗性的效果和作用机制初探

Effect and Action Mechanism of Exogenous NO in EnhancingMaize Resistance to Ustilago maydis

为探讨一氧化氮供体硝普纳(SNP)提高玉米对瘤黑粉病抗性的效果和作用机制,以高抗玉米瘤黑粉病自交系‘齐319’和高感玉米自交系‘掖478’为材料,研究不同浓度(0.02、0.05、0.1、0.5 mmol/L)SNP处理对玉米瘤黑粉菌菌丝生长和不同生长时期(0、5、10、15、20 d)玉米叶片生理特性的影响。结果表明:0.02、0.05 mmol/L浓度SNP对菌丝有明显抑制作用,处理玉米叶片后会产生一定的诱抗效果。外源喷施0.02 mmol/L浓度SNP能够提高玉米叶片中的抗氧化超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)、几丁质酶(CHT)、β-1,3-葡聚糖酶活性和游离脯氨酸(pro)含量,而其丙二醛(MDA)含量和脂氧合酶(LOX)活性有所降低。可见,外源NO可在一定程度上缓解瘤黑粉菌对玉米植株造成的伤害,提升玉米对瘤黑粉病的防治效果,其机制可能是通过提高玉米的多种抗氧化酶活性、渗透物质含量和抗病相关酶活性,从而提高玉米对瘤黑粉病的抗性。

To investigate effect and mechanism of nitric oxide(NO)donor sodium nitroprusside(SNP)on enhancement of maize resistance to Ustilago maydis,we used the highly resistant maize Ustilago maydis inbred line‘Qi 319’and the highly susceptible maize inbred line‘Ye 478’as the experimental materials.We conducted an experiment to investigate the effect of various SNP concentrations(0.02,0.05,0.1 and 0.5 mmol/L)on growth of Ustilago maydis hypha and the physiological parameters of maize leaves at various growth phases(0,5,10,15,20 d).The results demonstrated that SNP significantly inhibited mycelium at concentrations of 0.02 and 0.05 mmol/L,inducing a certain level of resistance in maize plants.Exogenous application of 0.02 mmol/L SNP enhanced the antioxidant activities of the enzymes superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),polyphenol oxidase(PPO),phenylalanine ammonia-lyase(PAL),chitinase(CHT),andβ-1,3-Glucanase as well as the level of free proline(pro)in maize leaves.Concurrently,it reduced the malondialdehyde(MDA)content and lipoxygenase(LOX)activity.In conclusion,exogenous NO can partially alleviate the damage caused by Ustilago maydis in maize plants and enhance their resistance to this pathogen.This enhancement is likely achieved by increasing the activity of various antioxidant enzymes,the accumulation of osmotic substances,and the activity of disease-resistance-related enzymes in maize.