The Melampsora lini AvrL567 avirulence genes are expressed in haustoria and their products are recognized inside plant cells
The Melampsora lini AvrL567 avirulence genes are expressed in haustoria and their products are recognized inside plant cells
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DOI：
10.1105/tpc.020040
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发表时间：
2004-03-01
期刊：
影响因子：
11.6
通讯作者：
Ellis, JG
中科院分区：
文献类型：
--
作者：
Dodds, PN;Lawrence, GJ;Ellis, JG
亚麻L基因等位基因编码核苷酸结合位点-富含Leu重复序列的胞内受体蛋白质，赋予对亚麻栅锈菌（Melampsora lini）（亚麻锈病）真菌的抗性。已知至少有11种不同的L抗性特异性，并且在M. lini定位于8个独立的基因座，其中一些基因座是复杂的并且编码多种特异性。我们发现了一个M Lini cDNA标记，在F2锈菌家族中与L5、L 6和L7抗性基因上的决定无毒力的复杂位点共分离。在无毒等位基因的基因组DNA重叠群中鉴定了两个相关的无毒候选基因，命名为AvrL 567-A和AvrL 567-B，而相应的毒力等位基因包含相关基因AvrL 567-C的单拷贝。根癌农杆菌介导的成熟AvrL 567-A或AvrL 567-B（但不包括AvrL 567-C）蛋白作为胞内产物在L. usitatissimum和Nicotiana tabacum（烟草）诱导了依赖于L5、L 6或L7抗性基因共表达的过敏反应样坏死。转基因L.将表达AvrL 567-A或AvrL 567-B（但不表达AvrL 567-C）的usitatissimum植物与含有L5、L 6或L7的抗性品系杂交。AvrL 567基因在锈菌吸器中表达，编码127个氨基酸的分泌蛋白。这些锈无毒蛋白的细胞内识别意味着它们被递送到宿主细胞中穿过植物膜。三个AvrL 567蛋白质序列的差异来自多样化选择，这与共同进化的军备竞赛一致。
The Linum usitatissimum (flax) L gene alleles, which encode nucleotide binding site-Leu rich repeat class intracellular receptor proteins, confer resistance against the Melampsora lini (flax rust) fungus. At least 11 different L resistance specificities are known, and the corresponding avirulence genes in M. lini map to eight independent loci, some of which are complex and encode multiple specificities. We identified an M. lini cDNA marker that cosegregates in an F2 rust family with a complex locus determining avirulence, on the L5, L6, and L7 resistance genes. Two related avirulence gene candidates, designated AvrL567-A and AvrL567-B, were identified in a genomic DNA contig from the avirulence allele, whereas the corresponding virulence allele contained a single copy of a related gene, AvrL567-C. Agrobacterium tumefaciens-mediated transient expression of the mature AvrL567-A or AvrL567-B (but not AvrL567-C) proteins as intracellular products in L. usitatissimum and Nicotiana tabacum (tobacco) induced a hypersensitive response-like necrosis that was dependent on coexpression of the L5, L6, or L7 resistance gene. An F1 seedling lethal or stunted growth phenotype also was observed when transgenic L. usitatissimum plants expressing AvrL567-A or AvrL567-B (but not AvrL567-C) were crossed to resistant lines containing L5, L6, or L7. The AvrL567 genes are expressed in rust haustoria and encode 127 amino acid secreted proteins. Intracellular recognition of these rust avirulence proteins implies that they are delivered into host cells across the plant membrane. Differences in the three AvrL567 protein sequences result from diversifying selection, which is consistent with a coevolutionary arms race.