Australian Research Council Centre of Excellence for Integrative Legume Research, School of Environmental and Life Sciences, The University of Newcastle, University Dr, Callaghan, NSW, 2308, Australia.
BMC Plant Biol. 2011 Mar 9;11:44. doi: 10.1186/1471-2229-11-44.
SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) genes are part of the regulation of diverse signalling events in plants. Current evidence shows SERK proteins function both in developmental and defence signalling pathways, which occur in response to both peptide and steroid ligands. SERKs are generally present as small gene families in plants, with five SERK genes in Arabidopsis. Knowledge gained primarily through work on Arabidopsis SERKs indicates that these proteins probably interact with a wide range of other receptor kinases and form a fundamental part of many essential signalling pathways. The SERK1 gene of the model legume, Medicago truncatula functions in somatic and zygotic embryogenesis, and during many phases of plant development, including nodule and lateral root formation. However, other SERK genes in M. truncatula and other legumes are largely unidentified and their functions unknown.
To aid the understanding of signalling pathways in M. truncatula, we have identified and annotated the SERK genes in this species. Using degenerate PCR and database mining, eight more SERK-like genes have been identified and these have been shown to be expressed. The amplification and sequencing of several different PCR products from one of these genes is consistent with the presence of splice variants. Four of the eight additional genes identified are upregulated in cultured leaf tissue grown on embryogenic medium. The sequence information obtained from M. truncatula was used to identify SERK family genes in the recently sequenced soybean (Glycine max) genome.
A total of nine SERK or SERK-like genes have been identified in M. truncatula and potentially 17 in soybean. Five M. truncatula SERK genes arose from duplication events not evident in soybean and Lotus. The presence of splice variants has not been previously reported in a SERK gene. Upregulation of four newly identified SERK genes (in addition to the previously described MtSERK1) in embryogenic tissue cultures suggests these genes also play a role in the process of somatic embryogenesis. The phylogenetic relationship of members of the SERK gene family to closely related genes, and to development and defence function is discussed.
体细胞胚胎发生受体样激酶（SERK）基因是植物中各种信号事件调节的一部分。目前的证据表明，SERK 蛋白在发育和防御信号通路中发挥作用，这些通路对肽和甾体配体都有反应。SERKs 通常在植物中作为小基因家族存在，拟南芥中有 5 个 SERK 基因。通过对拟南芥 SERKs 的研究获得的知识表明，这些蛋白质可能与广泛的其他受体激酶相互作用，并构成许多重要信号通路的基本组成部分。模式豆科植物蒺藜苜蓿的 SERK1 基因在体细胞和合子胚胎发生以及植物发育的许多阶段中发挥作用，包括根瘤和侧根形成。然而，蒺藜苜蓿和其他豆科植物中的其他 SERK 基因在很大程度上尚未被识别，其功能也未知。
为了帮助理解蒺藜苜蓿中的信号通路，我们已经鉴定并注释了该物种中的 SERK 基因。使用简并 PCR 和数据库挖掘，已经鉴定出并表达了另外 8 个 SERK 样基因。从其中一个基因扩增和测序的几个不同 PCR 产物与剪接变体的存在一致。在培养的在胚胎发生培养基上生长的叶片组织中，鉴定出的 8 个额外基因中有 4 个上调表达。从蒺藜苜蓿获得的序列信息用于鉴定最近测序的大豆（Glycine max）基因组中的 SERK 家族基因。
在蒺藜苜蓿中总共鉴定出 9 个 SERK 或 SERK 样基因，在大豆中可能有 17 个。5 个蒺藜苜蓿 SERK 基因是由大豆和 Lotus 中没有明显的复制事件产生的。在 SERK 基因中，剪接变体的存在以前没有报道过。在胚胎发生组织培养中，4 个新鉴定的 SERK 基因（除了先前描述的 MtSERK1 外）的上调表达表明这些基因也在体细胞胚胎发生过程中发挥作用。讨论了 SERK 基因家族成员与密切相关基因以及发育和防御功能的系统发育关系。
