The receptor for the fungal elicitor ethylene-inducing xylanase is a member of a resistance-like gene family in tomato
The receptor for the fungal elicitor ethylene-inducing xylanase is a member of a resistance-like gene family in tomato
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DOI：
10.1105/tpc.022475
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发表时间：
2004-06-01
期刊：
影响因子：
11.6
通讯作者：
Avni, A
中科院分区：
文献类型：
--
作者：
Ron, M;Avni, A
乙烯诱导木聚糖酶（EIX）是烟草（Nicotiana tabacum）和番茄（Lycopersicon esculentum）特定品种植物防御反应的有效激发子。对番茄LeEix基因座进行了定位克隆，鉴定出一个新的基因簇，并分离出LeEix1和LeEix2两个成员。与番茄抗Ve基因相似，LeEix1和LeEix2编码的氨基酸序列包含一个Leu拉链、一个含糖基化信号的细胞外富Leu重复结构域、一个跨膜结构域和一个含哺乳动物内吞信号的c端结构域。沉默LeEix基因的表达可以阻止EIX与EIX应答植物的细胞结合，从而抑制过敏反应。在对EIX无反应的烟草植株中，LeEix1或LeEix2基因的过表达都能使EIX结合，尽管只有LeEix2基因能传递诱导过敏反应的信号。在哺乳动物COS-7细胞中过表达LeEix2可使EIX结合，表明EIX激发子与LeEix2基因产物之间存在物理相互作用。LeEix蛋白的结构分析表明，它们属于一类具有受体介导的内吞作用信号的细胞表面糖蛋白。突变LeEix2的胞吞信号（Tyr 993 to Ala）使其丧失了诱导超敏反应的能力，提示胞吞作用在信号转导通路中起关键作用。
An ethylene-inducing xylanase (EIX) is a potent elicitor of plant defense responses in specific cultivars of tobacco (Nicotiana tabacum) and tomato (Lycopersicon esculentum). The LeEix locus in tomatoes was characterized by map-based cloning, which led to the identification of a novel gene cluster from which two members (LeEix1 and LeEix2) were isolated. Similar to the tomato Ve resistance genes in tomato plants, the deduced amino acid sequences encoded by LeEix1 and LeEix2 contain a Leu zipper, an extracellular Leu-rich repeat domain with glycosylation signals, a transmembrane domain, and a C-terminal domain with a mammalian endocytosis signal. Silencing expression of the LeEix genes prevented the binding of EIX to cells of an EIX-responsive plant and thus inhibited the hypersensitive response. Overexpression of either LeEix1 or LeEix2 genes in EIX-nonresponsive tobacco plants enabled the binding of EIX, although only LeEix2 could transmit the signal that induced the hypersensitive response. Overexpressing LeEix2 in mammalian COS-7 cells enables binding of EIX, indicating physical interaction between the EIX elicitor and LeEix2 gene product. Structural analysis of the LeEix proteins suggests that they belong to a class of cell-surface glycoproteins with a signal for receptor-mediated endocytosis. Mutating the endocytosis signal in LeEix2 (Tyr 993 to Ala) abolished its ability to induce the hypersensitive response, suggesting that endocytosis plays a key role in the signal transduction pathway.