Characterization of necrosis-inducing NLP proteins in Phytophthora capsici
| Autor: | Paul W. Tooley, Dylan Storey, Bao-Zhen Feng, Rong-Fei Lv, Xiao-Ping Zhu, Lu-Lu Fu, Xiuguo Zhang |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Phytophthora
PcNLPs protein expression Genetic Vectors Nicotiana benthamiana Virulence Agrobacterium Plant Science Biology Microbiology Chlorotic or necrotic response Necrosis Transformation Genetic Gene Expression Regulation Plant Botany Tobacco Plant defense against herbivory Phytophthora capsici Plant Diseases Oomycete Chlorosis Effector PcNLP genes fungi mRNA expression Proteins food and beverages biology.organism_classification Plants Genetically Modified Plant Leaves Mutation Mutagenesis Site-Directed Heterologous expression Capsicum Necrosis-inducing proteins (NLPs) Research Article |
| Zdroj: | BMC Plant Biology |
| ISSN: | 1471-2229 |
| DOI: | 10.1186/1471-2229-14-126 |
| Popis: | Background Effector proteins function not only as toxins to induce plant cell death, but also enable pathogens to suppress or evade plant defense responses. NLP-like proteins are considered to be effector proteins, and they have been isolated from bacteria, fungi, and oomycete plant pathogens. There is increasing evidence that NLPs have the ability to induce cell death and ethylene accumulation in plants. Results We evaluated the expression patterns of 11 targeted PcNLP genes by qRT-PCR at different time points after infection by P. capsici. Several PcNLP genes were strongly expressed at the early stages in the infection process, but the expression of other PcNLP genes gradually increased to a maximum at late stages of infection. The genes PcNLP2, PcNLP6 and PcNLP14 showed the highest expression levels during infection by P. capsici. The necrosis-inducing activity of all targeted PcNLP genes was evaluated using heterologous expression by PVX agroinfection of Capsicum annuum and Nicotiana benthamiana and by Western blot analysis. The members of the PcNLP family can induce chlorosis or necrosis during infection of pepper and tobacco leaves, but the chlorotic or necrotic response caused by PcNLP genes was stronger in pepper leaves than in tobacco leaves. Moreover, PcNLP2, PcNLP6, and PcNLP14 caused the largest chlorotic or necrotic areas in both host plants, indicating that these three genes contribute to strong virulence during infection by P. capsici. This was confirmed through functional evaluation of their silenced transformants. In addition, we further verified that four conserved residues are putatively active sites in PcNLP1 by site-directed mutagenesis. Conclusions Each targeted PcNLP gene affects cells or tissues differently depending upon the stage of infection. Most PcNLP genes could trigger necrotic or chlorotic responses when expressed in the host C. annuum and the non-host N. benthamiana. Individual PcNLP genes have different phytotoxic effects, and PcNLP2, PcNLP6, and PcNLP14 may play important roles in symptom development and may be crucial for virulence, necrosis-inducing activity, or cell death during infection by P. capsici. |
| Databáze: | OpenAIRE |
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