非寄主抗病性是一种普遍的自然现象, 该文通过建立拟南芥-大豆疫霉菌(Arabidopsis thaliana-Phytophthora sojae)非寄主互作系统, 筛选对大豆疫霉菌感病的拟南芥突变体, 为研究植物对卵菌的非寄主抗病性遗传机制奠定基础。以大豆疫霉菌游动孢子接种拟南芥T-DNA插入突变体离体叶片, 从代表12 000个独立转化株系的40 000株T₃代T-DNA插入拟南芥突变体中获得一系列对大豆疫霉菌感病的突变体。其中突变体581-51感病性状表现稳定, 离体叶片接菌后3天内出现明显的水渍状病斑, 4–5天后产生大量卵孢子和/或孢子囊。细胞学观察发现有典型的吸器形成。Southern杂交和遗传分析结果表明, 581-51突变体含有4个T-DNA插入事件, 其感病性状可能由隐性单基因控制。

Phytophthora sojae and Arabidopsis thaliana were used in this study as a nonhost plant-oomycete interaction system to investigate the genetic basis of nonhost resistance against oomycete pathogens in plants. A collection of more than 40 000 T₃ A. thaliana T-DNA mutant plants representing 12 000 independent insertion lines were screened by inoculating detached leaves with P. sojae zoospores, and the susceptible mutant was re-confirmed by pathogen inoculation and cytological characterization. A number of P. sojae-susceptible A. thaliana mutants were successfully obtained, and one of them, mutant 581-51, was shown to be stably susceptible to P. sojae infection. Water-soaked lesions formed on the detached leaves within 3 days, as did oospores and sporangia 4–5 days after inoculation with P. sojae zoospores. Cytological characterization revealed the formation of haustoria-like structures. Southern analysis showed the presence of four T-DNA insertion events in the mutant. Genetic analysis indicated that the susceptibility to infection by the nonhost pathogen P. sojae in the mutant 581-51 was likely controlled by a single recessive gene.