Plant-Microbe Interactions, Botanical Institute, University of Karlsruhe, Hertzstrasse 16, D-76187 Karlsruhe, Germany.
Mol Plant Microbe Interact. 2010 Jan;23(1):67-81. doi: 10.1094/MPMI-23-1-0067.
Comparative analyses of genome sequences from several plant-infecting fungi have shown conservation and expansion of protein families with plant disease-related functions. Here, we show that this hypothesis can be extended to mutualistic symbiotic fungi. We have identified a gene encoding an Era (Escherichia coli Ras)-like GTPase in the rice blast fungus Magnaporthe oryzae and found that it is orthologous to the mature amino terminal part of the Gin1 protein from the arbuscular mycorrhizal (AM) fungus Glomus intraradices. M. oryzae Erl1 is required for full root virulence. Appressoria formation was not severely affected in Deltaerl1 strains, but invasive hyphae grew slower than in the wild type. Root browning defect of Deltaerl1 strains could be complemented by the AM gene under the control of the ERL1 promoter. Erl1 and Gin-N localized to the nucleus when carboxy-terminally labeled with green fluorescent protein (GFP). However, amino-terminal GFP-tagged versions of the proteins expressed in Aspergillus nidulans were shown to localize in the cytoplasm and to cause polarity defects. These data suggest that Erl1 and Gin-N are orthologs and might be involved in the control of hyphal growth in planta. This is the first characterization of an Era-like GTPase in filamentous fungi.
对几种植物病原真菌的基因组序列进行比较分析表明，与植物病害相关功能的蛋白质家族具有保守性和扩展性。在这里，我们表明这一假设可以扩展到互惠共生的真菌。我们在稻瘟病菌 Magnaporthe oryzae 中鉴定出一个编码 Era（大肠杆菌 Ras）样 GTPase 的基因，并发现它与丛枝菌根（AM）真菌 Glomus intraradices 的 Gin1 蛋白的成熟氨基末端部分同源。M. oryzae Erl1 是完全根致病性所必需的。Deltaerl1 菌株的附着胞形成没有受到严重影响，但侵入性菌丝的生长速度比野生型慢。Deltaerl1 菌株的根褐变缺陷可以通过 AM 基因在 ERL1 启动子的控制下得到互补。用绿色荧光蛋白（GFP）羧基末端标记 Erl1 和 Gin-N 时，它们定位于细胞核中。然而，在 Aspergillus nidulans 中表达的氨基末端 GFP 标记版本的蛋白质被证明定位于细胞质中，并导致极性缺陷。这些数据表明，Erl1 和 Gin-N 是同源物，可能参与控制植物体内菌丝的生长。这是丝状真菌中第一个 Era 样 GTPase 的特征。
