冠菌素诱导甘蓝幼苗抗黑腐病及其机理初步研究

以甘蓝 Brassica oleracea L.感病品种"庆丰"为材料,通过叶面喷施冠菌素(coronatine,COR)和人工接种黑腐病菌——野油菜黄单胞菌野油菜致病变种(Xanthomonas campestris pv.campestris)的方法,研究了COR诱导甘蓝幼苗抗黑腐病的效果及其生理生化机制。结果表明, COR在质量浓度为0.01、0.1和1.0 mg/L下均具有诱导甘蓝幼苗抗黑腐病的效果,其中1.0 mg/L 处理的病情指数为38.2,诱抗率为43.7%,诱导抗病效果最好。与对照相比,随着COR质量浓度的提高,叶片中过氧化氢酶(CAT)活性和超氧阴离子(O2-)产生的速率明显增加,而过氧化物酶(POD)的活性增加不明显,超氧化物歧化酶(SOD)活性和丙二醛(MDA)的含量明显下降。表明COR具有诱导甘蓝幼苗抗黑腐病的作用,而这种作用可能与COR能调控甘蓝幼苗中抗氧化酶活性、提高O2-产生速率以及降低MDA的含量相关。

Study on resistance of cabbage seedlings to black rot induced by coronatine treatment and its biochemical and physiological mechanism

The resistance effect and physiological mechanism of anti-black rot induced by coronatine (COR) in cabbage seedlings were studied by foliar application of COR and inoculation of black rot bacteria (Xanthomona scampestris pv. campestris).Susceptible cultivar cabbage (Brassica oleracea L.)Qing Feng was used as the seedling material.The results showed that COR induced black rot resistant in cabbage seedlings at the tested concentration of 0.01, 0.1 and 1.0 mg/L. The treatment of COR at 1.0 mg/L showed the best inductive effect,with the disease index as 38.2 and induced resistance rate as 43.7%.Comparing with that of the control,the catalase (CAT) activity and superoxide anion (O₂^-) generation rate increased significantly in leaf,but the superoxide dismutase (SOD) activity and malondialdehyde (MDA) were obviously decreased as the COR concentration increased. In summary,COR could induce black rot resistance in cabbage seedlings,which might be related with the variation of antioxidant enzyme activity,O₂^- generation rate and MDA content that induced by COR.