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研究2,6-二氯异烟酸(INA)对采后香蕉果实抗病性的诱导作用和早期果皮活性氧含量、抗病相关酶活性及基因表达量的变化。结果表明:香蕉果实经0.5g·L-1INA处理后0、3、6、12、24h接种炭疽病菌孢子,贮藏8d后,INA处理果实的病斑直径比对照果实的明显减小;INA处理果实的H2O2含量和NADPH氧化酶活性分别在6h和3～12h明显高于对照;过氧化氢酶(CAT)活性均明显低于对照,抗坏血酸氧化酶(APX)活性稍低于对照,CAT和APX基因的表达也受到一定的抑制;内切几丁质酶(CHI)活性在0、3、6、12h高于对照,外切CHI活性在24h内逐步增加,而对照保持不变;CHI1和CHI2基因的表达在前6h略高于对照。综上所述,INA诱导采后香蕉果实抗病性增加与其早期活性氧水平及抗病相关酶活性增加有密切关系,由于活性氧合成酶活性增加、清除酶活性减少而产生的高水平活性氧可能作为信号分子启动了抗病应答反应。
To study the effects of 2,6-dichloroisonicotinic acid (INA) on the disease resistance of postharvest banana fruit and the changes of reactive oxygen species content, disease-related enzyme activity and gene expression in early peel. The results showed that the spores of B. anthracis were inoculated at 0, 3, 6, 12 and 24 h after being treated with 0.5 g · L-1INA. After 8 days of storage, the diameter of lesion in fruit of INA treatment was significantly lower than that of the control. INA treatment H2O2 content and NADPH oxidase activity were significantly higher than those of the control at 6h and 3 ~ 12h respectively; the activities of catalase (CAT) were significantly lower than those of the control and the activities of ascorbate oxidase (APX) (CHI) activity was higher at 0, 3, 6 and 12h than that of the control. The activity of exogenous CHI gradually increased within 24 hours while the control remained unchanged. The CHI1 and CHI2 genes The expression was slightly higher than the control in the first 6 hours. In summary, INA-induced post-harvest banana fruit disease resistance increased with its early level of reactive oxygen species and resistance-related enzyme activity is closely related to increased active oxygenase activity, scavenging enzyme activity to reduce the high level of reactive oxygen species May act as a signaling molecule to initiate the disease response response.