水杨酸诱导不结球白菜抗黑斑病机制的探讨

以不结球白菜感黑斑病品种短白梗为材料,于两叶一心期用05mmol·L-1水杨酸(SA)进行叶面喷雾处理,用半定量RT-PCR技术检测叶片中Bcchi、BcPR4、BcAF基因的表达变化,并在SA处理后24 h接种甘蓝链格孢菌(Alternaria brassicicola),研究抗病相关物质的变化,以探讨SA 诱导的抗病机制.结果表明,SA喷雾处理后显著诱导了BcAF、BcPR4、Bcchi在短白梗中的表达;接种后,经SA处理的短白梗中,48 h前SOD活性、12 h后POD活性、48 h前PPO活性和0～12 h与84 h后H2O2含量均高于未经处理的,而CAT活性在处理36h后低于未经处理的.用SA 对短白梗进行喷雾处理可明显降低其病情指数,表明SA诱导系统获得性抗性在提高黑斑病抗性方面起到重要作用.

Study on the mechanism of induced resistance to black spot disease by SA in non-heading Chinese cabbage

0. 5 mmol· L~(-1) SA was used to spray leaves of Duanbaigeng which is susceptible to black spot disease at two-leaves and one heart stage, and semi-quantitative RT-PCR was done to detect the expression of Bcchi, BcPR4, BcAF in leaves. Alternaria brassicicola was inoculated 24 h after SA treatment in order to study the changes of resistance-related materials to know better of the resistant mechanism of SA induction. The results showed the expression of Bcchi, BcAF and BcPR4 was significantly induced and enhanced by SA in Duanbaigeng. After inoculation, the activities of SOD (0-48), POD ( 12 h later) , PPO (0-48h) and the content of H_2O_2 (0 - 12 h and 84 h later) were all higher than those unprocessed by SA in Duanbaigeng. However, CAT active was lower than that unprocessed after 36 h-treatment. SA can reduce the disease index which indicates that systematically acquired resistance induced by SA plays an important role in the resistance to Alternaria brassicicola in non-heading Chinese cabbage.