摘要
用厌气技术诱发软腐病,测定了大白菜幼苗茎组织的5种生理生化反应和病菌在组织内的数量及果胶裂解酶(PGTL)作用的变化。组织电解质渗漏(EL)最早发生,同时伴有还原糖(RS)、特别是总可溶性糖(TSS)和游离氨基酸(FAA)含量的下降。10小时后,组织内病菌数量明显增高;20小时后,病菌PGTL作用加强,酶解活性平稳提高,并在80-96小时后达到高峰。随病害诱发的持续,EL及RS、TSS、FAA含量的下降持续发生。在上述反应的同时,寄主细胞壁蛋白质(CWP)含量最迟在24小时后增高。CWP在体外测定中对病菌PGTL有强烈的抑制作用;组织二元酚含量随诱病过程而呈阶段性升降变化。以上反应在抗感不同的品种间有明显差别:感病品种在发病前RS、TSS、FAA含量高;CWP、二元酚含量低,发病后RS、TSS、FAA含量下降快,CWP含量或下降或提高的时间推迟,二元酚含量升降幅度小;病菌数量增加快,PGTL活性高;而抗病品种的反应大致与此相反。
Anaerobic treatment was used for inducing soft rot of young stems of chinese cabbage inoculated with Erwinia carotovora subsp. carotovora and the 5 kinds of responses of the host were tested, to understand the pathogen-host interactions involved in the transformation from latent infection to pathogenesis in the disease. The electrolyte leakage (EL) of the plant tissues occurred immediately after anaerobic treatment, accompanied by the content decrease of reductive and soluble sugars (RS and TSS), and free amino acids (FAA). About 10hr later, a 10—13~3 times increase of the in vivo bacterial numbers was detected by recovering the inoculated bacteria with rifampicin resistance, followed by enhancement of polygalacturonic acid lyase (PGTL) of the pathogen at 5—40 times in tissues of different cvs. The sustained reduction of RS, TSS, and FAA contents, and enhancement of the bacterial PGTL activity took place as extensiopn of anaerobic treatment. The variances of binary phenyl (PB) and cell protein (CWP) was the other responses of the host. The CWP was able to inhibit the PGTL activity in the tests in vitro, and increase its in vivo content before 24hr of anaerobic treatment. While the PB content showed fluctuations as disease induction. The contents of sugars, FAA and CWP were also found to be related to pathogenesis and host resistance. In susceptible cvs, the higher constitutive contents of sugars and FAA, and their reduction as disease induction were corelated positively to higher population and PGTL activity of the pathogen. While in resistant cvs, the lower contents and their decrease of sugars and FAA, and higher content and its increase as disease development were corelated positively to the lower numbers of the bacteria and lower activity of PGTL enzyme.
出处
《山东科学》
CAS
1993年第2期76-81,共6页
Shandong Science
关键词
大白菜
软腐病
病菌致病
Chinese cabbage
soft rot erwinia
pathogenesis
pathogenicity
cell wall protein
