Phytophthora parasitica多聚半乳糖醛酸酶基因族之分子選殖與功能性分析
Molecular cloning and functional analysis of a gene family encoding endopolygalacturonase in Phytophthora parasitica
Date Issued
2007
Date
2007
Author(s)
Wu, Chih-Hang
DOI
en-US
Abstract
Phytophthora parasitica is an oomycete plant pathogen that causes severe disease in a wide variety of plant species. It has been shown in our previous study that pppg1, which encodes endopolygalacturonase (endoPG), is highly induced during interaction of P. parasitica with the host plant, suggesting its involvement in the process of plant infection. Southern blot analysis using pppg1 as the probe indicated the presence of other sequences homologous to pppg1 in the genome of P. parasitica (Yan and Liou, 2005). To gain insight into to the functional characteristics of these genes, we screened the genomic library of P. parasitica using the fragments amplified by degenerate primers which were designed from the conserve region of Phytophthora endoPGs. The results indicated that there exists an endoPG multigene family with at least 13 members in P. parasitica. Besides, analysis of eight recombinant proteins obtained from the yeast Pichia pastoris by heterologous expression demonstrated that these proteins process polygalacturonase activity. By using PVX agroinfection to express these endoPGs systemically in Nicotiana benthamiana, we showed that these endoPGs caused distinct effects on plants and these effects were abolished when hydrolysis activity and signal peptide were lost by site direct mutagenesis or deletion. Moreover, the effects caused by these endoPGs were different when expressed in tomato (Lycopersicon esculentum) and Nicotiana tabacum. The results here showed that these endoPGs have distinct biological characteristics in planta.
Subjects
疫病菌
多聚半乳糖醛酸酶
PVX agroinfection。
Phytophthora parasitica
endopolygalacturonase
PVX agroinfection.
Type
other