期刊
PLANT JOURNAL
卷 83, 期 4, 页码 610-624出版社
WILEY
DOI: 10.1111/tpj.12913
关键词
effector; 3D structure; plant cell translocation; plant disease resistance; avirulence protein; Leptosphaeria maculans; Brassica napus
资金
- ANR [ANR-14-CE19-0019]
- US National Science Foundation [IOS-0924861]
- Agence Nationale de la Recherche (ANR) [ANR-14-CE19-0019] Funding Source: Agence Nationale de la Recherche (ANR)
The avirulence gene AvrLm4-7 of Leptosphaeria maculans, the causal agent of stem canker in Brassica napus (oilseed rape), confers a dual specificity of recognition by two resistance genes (Rlm4 and Rlm7) and is strongly involved in fungal fitness. In order to elucidate the biological function of AvrLm4-7 and understand the specificity of recognition by Rlm4 and Rlm7, the AvrLm4-7 protein was produced in Pichia pastoris and its crystal structure was determined. It revealed the presence of four disulfide bridges, but no close structural analogs could be identified. A short stretch of amino acids in the Cterminus of the protein, (R/N)(Y/F)(R/S)E(F/W), was well-conserved among AvrLm4-7 homologs. Loss of recognition of AvrLm4-7 by Rlm4 is caused by the mutation of a single glycine to an arginine residue located in a loop of the protein. Loss of recognition by Rlm7 is governed by more complex mutational patterns, including gene loss or drastic modifications of the protein structure. Three point mutations altered residues in the well-conserved C-terminal motif or close to the glycine involved in Rlm4-mediated recognition, resulting in the loss of Rlm7-mediated recognition. Transient expression in Nicotiana benthamiana (tobacco) and particle bombardment experiments on leaves from oilseed rape suggested that AvrLm4-7 interacts with its cognate Rproteins inside the plant cell, and can be translocated into plant cells in the absence of the pathogen. Translocation of AvrLm4-7 into oilseed rape leaves is likely to require the (R/N)(Y/F)(R/S)E(F/W) motif as well as an RAWG motif located in a nearby loop that together form a positively charged region. Significance Statement The crystal structure of AvrLm4-7, an effector of the fungal agent of oilseed rape stem canker which confers recognition by two resistance genes, was determined. A combination of transient in planta expression, study of AvrLm4-7 polymorphisms in fungal populations under resistance gene selection pressure and site-directed mutagenesis allowed us to identify motifs and domains relevant for interaction with the resistance genes and possibly for translocation into plant cells and function.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据