The Medicago truncatula lysine motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes
The Medicago truncatula lysine motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes
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DOI：
10.1104/pp.106.084657
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发表时间：
2006-09-01
期刊：
影响因子：
7.4
通讯作者：
Gough, Clare
中科院分区：
文献类型：
--
作者：
Arrighi, Jean-Francois;Barre, Annick;Gough, Clare
根瘤菌结瘤因子是豆科植物启动结瘤过程的关键共生信号。在6个控制Nod因子信号通路的苜蓿基因中，Nod因子感知（NFP）被报道为Nod因子受体的候选基因。在这里，我们提供了进一步的证据，表明NFP是赖氨酸基序（LysM）受体样激酶（RLK）。研究表明，NFP的表达与感染丝线的发育有关，并参与了感染过程。与保守的激酶结构域序列的偏离一致，NFP没有表现出自磷酸化活性，这表明NFP需要与活性激酶结合，或者具有不同于经典激酶的不寻常的功能特征。9个新基因的鉴定表明，与非豆科植物拟南芥（Arabidopsis thaliana）或水稻（Oryza sativa）相比，拟南芥LysM-RLK家族至少有17个成员，可分为3个亚家族。三个LysM结构域可以在结构上预测所有M. truncatula LysM- rlk蛋白，而一个亚家族，包括NFP，其特征是偏离保守的激酶序列。大多数新发现的基因被发现在根和根瘤中表达，这表明这类受体可能比以前已知的更广泛地参与根瘤形成。
Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide further evidence for this by showing that NFP is a lysine motif (LysM)-receptor-like kinase (RLK). NFP was shown both to be expressed in association with infection thread development and to be involved in the infection process. Consistent with deviations from conserved kinase domain sequences, NFP did not show autophosphorylation activity, suggesting that NFP needs to associate with an active kinase or has unusual functional characteristics different from classical kinases. Identification of nine new M. truncatula LysM-RLK genes revealed a larger family than in the nonlegumes Arabidopsis (Arabidopsis thaliana) or rice (Oryza sativa) of at least 17 members that can be divided into three subfamilies. Three LysM domains could be structurally predicted for all M. truncatula LysM-RLK proteins, whereas one subfamily, which includes NFP, was characterized by deviations from conserved kinase sequences. Most of the newly identified genes were found to be expressed in roots and nodules, suggesting this class of receptors may be more extensively involved in nodulation than was previously known.