Ditt Renata F, Kerr Kathleen F, de Figueiredo Paul, Delrow Jeff, Comai Luca, Nester Eugene W
Department of Biology, University of Washington, Seattle 98195, USA.
Mol Plant Microbe Interact. 2006 Jun;19(6):665-81. doi: 10.1094/MPMI-19-0665.
The pathogen Agrobacterium tumefaciens infects a broad range of plants, introducing the T-DNA into their genome. Contrary to all known bacterial phytopathogens, A. tumefaciens lacks the hypersensitive response-inducing hrp genes, although it introduces numerous proteins into the plant cell through a type IV secretion system. To understand the timing and extent of the plant transcriptional response to this unusual pathogen, we used an Arabidopsis 26,000-gene oligonucleotide microarray. We inoculated Arabidopsis cell cultures with an oncogenic Agrobacterium strain and analyzed four biological replicates to identify two robust sets of regulated genes, one induced and the other suppressed. In both cases, the response was distinct at 48 h after infection, but not at 24 h or earlier. The induced set includes genes encoding known defense proteins, and the repressed set is enriched with genes characteristic of cell proliferation even though a growth arrest was not visible in the inoculated cultures. The analysis of the repressed genes revealed that the conserved upstream regulatory elements Frankiebox (also known as "site II") and Telobox are associated with the suppression of gene expression. The regulated gene sets should be useful in dissecting the signaling pathways in this plant-pathogen interaction.
病原菌根癌农杆菌可感染多种植物，并将转移DNA（T-DNA）导入植物基因组。与所有已知的细菌性植物病原菌不同，根癌农杆菌缺乏诱导过敏反应的hrp基因，尽管它通过IV型分泌系统将大量蛋白质导入植物细胞。为了解植物对这种特殊病原菌转录反应的时间和程度，我们使用了拟南芥26000基因寡核苷酸微阵列。我们用一种致癌性农杆菌菌株接种拟南芥细胞培养物，并分析了四个生物学重复样本，以鉴定出两组稳定的调控基因，一组是诱导表达的，另一组是被抑制表达的。在这两种情况下，感染后48小时的反应是明显的，但在24小时或更早的时候则不明显。诱导表达的基因集包括编码已知防御蛋白的基因，而被抑制表达的基因集中富含细胞增殖特征性的基因，尽管在接种的培养物中未观察到生长停滞。对被抑制基因的分析表明，保守的上游调控元件Frankiebox（也称为“位点II”）和Telobox与基因表达的抑制有关。这些调控基因集将有助于剖析这种植物-病原菌相互作用中的信号传导途径。
