全 文 ：植物学报 Chinese Bulletin of Botany 2015, 50 (5): 628–636, www.chinbullbotany.com
doi: 10.11983/CBB14119
——————————————————
收稿日期: 2014-07-14; 接受日期: 2014-11-13
基金项目: 国家重点基础研究发展计划(No.2013CB127103)和国家自然科学基金(No.31300249, No.31000092)
* 通讯作者。E-mail: chentong@ibcas.ac.cn
LysM蛋白介导植物免疫防卫反应及其信号激发的研究进展
季东超, 宋凯, 邢晶晶, 陈彤*, 田世平
中国科学院植物研究所北方资源植物重点实验室, 北京 100093
摘要 溶解素基序(LysM)是一类普遍存在于大多数有机体中的蛋白质结构域。植物细胞中含有LysM结构域的蛋白能够识
别不同种类含有N-乙酰葡糖胺结构的配体分子, 从而启动植物对病原菌的特异防御反应。作为一种重要的模式识别受体,
LysM结构域蛋白通过不同形式的寡聚化、受体类胞质激酶BIK1和MAPK级联反应向下游传递信号, 而病原菌能够通过其分
泌的效应蛋白特异性识别或修饰模式识别受体, 规避植物细胞中病原体相关分子模式诱导的免疫反应。该文主要综述受体
激酶/蛋白在病原菌激发子识别和防卫反应启动中的作用。
关键词 防卫反应, 免疫, 溶解素基序, 病原菌
季东超, 宋凯, 邢晶晶, 陈彤, 田世平 (2015). LysM蛋白介导植物免疫防卫反应及其信号激发的研究进展. 植物学报 50,
628–636.
在与微生物长期协同进化过程中, 植物逐渐进化
出与动物类似的先天免疫机制(innate immunity), 以
识别来自病原菌的非寄主分子结构或效应蛋白, 启动
主动防卫反应途径。细菌肽聚糖 (peptidoglycan,
PGN)和真菌几丁质等微生物聚糖都是植物免疫激活
过程中重要的激发子。植物细胞中存在一类含有溶解
素基序(lysin motif, LysM)结构域的蛋白, 它能够识别
不同种类含有N-乙酰葡糖胺(GlcNAc)结构的配体分
子, 从而启动植物对病原菌的特异防御反应。本文将
主要综述该类LysM受体激酶/蛋白在病原菌激发子识
别和防御反应启动中的作用。
1 质膜模式识别受体及其在植物免疫激
活过程中的作用
自然界中, 植物长期定植于存在各种微生物的复杂环
境中, 其根系周围往往生活着大量细菌、真菌和病毒
(Mendes et al., 2011), 这些有机体之间的相互作用
有些是有益的, 而相当多的部分是有害的(Oldroyd
and Robatzek, 2011)。受到病原菌侵袭时, 植物能够
迅速启动先天免疫防卫反应, 其先天免疫被激活后产
生两类主要的防卫反应途径: (1) 细胞质膜上的模式
识别受体(pattern recognition receptors, PRRs)识别
病原菌表面的病原体相关分子模式(pathogenasso-
ciated molecular patterns, PAMPs)并启动防卫反应,
这个过程称为病原体相关分子模式诱导的免疫反应
(PAMP-triggered immunity, PTI); (2) 由于病原菌分
泌的效应蛋白 (effector)或者无毒蛋白 (avirulence
protein)能够抑制PTI, 植物细胞还进化出另一类防卫
反应模式, 即利用专化性抗病蛋白(R蛋白)识别病原
菌释放的效应蛋白, 从而起始下游的专化性防卫反
应, 该过程称为效应蛋白诱导的免疫反应(effector-
triggered immunity, ETI) (陈晓亚和薛红卫, 2012)。
在PTI反应中, 植物免疫系统主要运用两种类型
的质膜PRRs, 即富含亮氨酸重复序列的受体蛋白
(leucine-rich repeat receptor protein, LRR-RP)/受体
激酶(leucine-rich repeat receptor kinase, LRR-RK)
和含有溶解素基序(LysM)结构域的受体激酶/蛋白。
二者可以根据胞外结构域类型加以区分, 其中LRR-
RP/LRR-RK已被广泛报道, 它们通过结合病原体相
关分子模式, 招募类受体激酶BAK1 (BRI1-associa-
ted receptor kinase 1)或其它成员, 随后形成活化的
受体复合物, 通过丝氨酸/苏氨酸蛋白激酶介导的蛋
白磷酸化直接激活下游的胞内激酶BIK1 (Botry-
tis-induced kinase 1)及其它PBL (PBS1-like kina-
ses)家族成员 , 介导免疫反应 (陈晓亚和薛红卫 ,
·专题论坛·
季东超等: LysM蛋白介导植物免疫防卫反应及其信号激发的研究进展 629

2012)。此过程伴随质膜钙离子通道活性提高、胞质
钙离子浓度升高、钙调蛋白激酶(calcium-depend-
ent protein kinase, CDPK)激活、活性氧爆发以及丝
裂酶原活化蛋白激酶(mitogen-activated protein kin-
ase, MAPK)级联反应的激活等一系列过程, 最终核
内转录因子被激活, 防卫反应基因开始表达(陈晓亚
和薛红卫, 2012)。我们较为熟悉的如细菌鞭毛蛋白
Flagellin或伸长因子EF-Tu能分别被拟南芥 (Arabi-
dopsis thaliana) LRR-RKs FLS2 (flagellin-sensitive
2)或EFR (EF-Tu receptor)识别; 番茄(Solanum ly-
copersicum)中的LRR-RPs LeEIX1和LeEIX2能够介
导对真菌细胞壁木聚糖酶的感知(Zipfel, 2008; Boller
and Felix, 2009)。遗传分析结果表明, LysM受体激酶/
蛋白的胞外结构域在植物细胞识别病原菌表面的相
关聚糖物质, 及对病原菌侵染产生免疫反应的过程中
起重要作用(Kaku et al., 2006; Miya et al., 2007;
Wan et al., 2008; Kishimoto et al., 2010; Shimizu et
al., 2010; Willmann et al., 2011)。此外, LysM受体激
酶也是豆类与根瘤菌建立共生以及植物丛枝真菌产
生所需的重要元件(Limpens et al., 2003; Madsen et
al., 2003; Radutoiu et al., 2003; Gough and Culli-
more, 2011; Op den Camp et al., 2011)。
2 LysM介导植物细胞对含有N-乙酰葡
糖胺多糖的病原体分子模式的识别
溶解素基序(LysM)是一类普遍存在于大多数有机体
中的蛋白质结构域, 长度约为40 aa (Bateman and
Bycroft, 2000; Buist et al., 2008; Zhang et al.,
2009)。其三维结构中的2个α螺旋垛叠在双股反向平
行的β折叠结构的一侧(Bateman and Bycroft, 2000;
Bielnicki et al., 2006; Mulder et al., 2006)。几个LysM
被短肽间隔开 , 从而形成1个典型的LysM结构域
(Buist et al., 1995; Ohnuma et al., 2008)。最早关于
LysM结构域的报道来自分泌型的细菌水解酶, 它主
要参与细菌细胞壁的生物发生、修饰和降解, 包括溶
菌酶、自溶素和转糖基酶3类。肽聚糖广泛存在于真
细菌中的革兰氏阳性菌和革兰氏阴性菌的细胞壁, 由
间隔出现的β (1-4) N-乙酰胞壁酸(MurNAc)、N-乙酰
葡糖胺(GlcNAc)残基以及连接相邻寡聚杂多糖链的
肽桥组成(Schleifer and Kandler, 1972; Glauner et
al., 1988)。细菌LysM主要介导含有LysM结构域的蛋
白与细菌表面糖类结构(如肽聚糖)的物理接触。细菌
中含LysM结构域的水解酶(细胞溶解素和几丁质酶)
能够断裂位于肽聚糖MurNAc和GlcNAc残基间以及
几丁质GlcNAc残基间的1,4-O-糖苷键(Ponting et al.,
1999; Buist et al., 2008; Ohnuma et al., 2008)。因此,
LysM被认为是与含GlcNAc结构的多糖相结合的关键
结构(Buist et al., 2008; 江聪等, 2014)。
众所周知, 微生物中许多含GlcNAc结构的寡聚
糖能够启动植物细胞防卫反应等重编程过程。已有文
献报道了肽聚糖、几丁质及其寡聚片段在不同的植物
中均能触发免疫防卫反应的病原体相关模式 (Shi-
buya and Minami, 2001; Gust et al., 2007; Erbs et
al., 2008; Hamel and Beaudoin, 2010; Gough and
Cullimore, 2011; Kombrink et al., 2011)。目前, 已发
现的大多数植物LysM蛋白都与来自病原菌的聚糖水
解或者识别有关, LysM结构域表现出与微生物LysM
结构域蛋白类似的配体特异性(Limpens et al., 2003;
Madsen et al., 2003; Radutoiu et al., 2003; Kaku et
al., 2006; Miya et al., 2007; Wan et al., 2008; Shi-
mizu et al., 2010; Op den Camp et al., 2011; Will-
mann et al., 2011)。另一方面, 微生物中含有LysM
结构域的蛋白往往具酶活性, 能够修饰含有GlcNAc
结构的底物, 而一些植物细胞LysM蛋白能够与含有
GlcNAc结构的配体结合, 但不具酶活性, 另一些植
物细胞LysM蛋白不能与上述微生物配体结合, 但能
够介导植物对微生物GlcNAc信号的响应; 然而, 植
物细胞中许多LysM受体激酶/蛋白以及分泌型LysM
蛋白的配体特异性和功能仍然未知, 它们也可能参与
多糖配体的识别。这些蛋白质归为4个家族, 即缺少
胞内激酶域的膜锚定LysM蛋白、LysM受体激酶、胞
外非分泌LysM蛋白和胞内非分泌LysM蛋白(Arrighi
et al., 2006; Zhang et al., 2009; Fliegmann et al.,
2011)。根据不同的激酶结构域特征, LysM受体激酶
可进一步被细分为两枝(LYKs或LysM-RLK-I; LYK相
关LYRs或LysM-RLK-II)。拟南芥中的LysM受体激酶/
蛋白详见表1。


630 植物学报 50(5) 2015

表1 拟南芥基因组中的LysM受体激酶/蛋白(Mendes et al., 2011)
Table 1 LysM-containing receptors / proteins in Arabidopsis (Mendes et al., 2011)
基因名称
(别称)
基因号 LysM结构域
布局
配体 受体
类型
是否为功能性
激酶(激酶类型)
突变体对几
丁质处理
后的响应
备注
AtCERK1
(AtLYK1,
LysM RLK1)
At3g21630 I + II + IV 几丁质 LysM-RLK-I
LYK
是
(RD kinase)
不敏感 参与肽聚糖感知;
LjNFR1横向同源
AtLYK2 At3g01840 * + * + V 未知 LysM-RLK-II
LYR
否
(Pseudo kinase)
正常 LjNFR5横向同源II
AtLYK3 At1g51940 * + VII + * 未知 LysM-RLK-I
LYK
是
(RD kinase)
正常
AtLYK4 At2g23770 I + II + III 几丁质 LysM-RLK-II
LYR
否
(Pseudo kinase)
中等敏感 LjNFR5横向同源I
AtLYK5 At2g33580 I + II + III 几丁质 LysM-RLK-II
LYR
否
(Pseudo kinase)
正常
AtLYP1
(CEBiP-like1,
LYM2)
At2g17120 * + VI + VII 几丁质 LYP – 正常 C末端包含GPI锚定信号;
OsCEBiP直系同源
AtLYP2
(CEBiP-like2,
LYM1)
At1g21880 * + VI + VIII 肽聚糖 LYP – 正常 C末端包含GPI锚定信号;
与OsLYP4和OsLYP6直系
同源
AtLYP3
(CEBiP-like3,
LYM3)
At1g77630 * + VI + VIII 肽聚糖 LYP – 正常 C末端包含GPI锚定信号;
与OsLYP4和OsLYP6直系
同源
* 该LysM结构域序列保守性较低。LYK: 溶解素基序类受体激酶; LYR: 相关的溶解素基序类受体激酶; CERK: 几丁质激发子受体
激酶; CEBiP: 几丁质激发子结合蛋白; LYP: 溶解素基序类受体蛋白; LYM: 含有溶解素基序结构域的糖基磷脂酰肌醇锚定蛋白
* The LysM domains have less sequence conservation. LYK: LysM receptor-like kinase; LYR: LYK-related; CERK: Chitin elicitor
receptor kinase; CEBiP: Chitin elicitor binding protein; LYP: LysM receptor-like protein; LYM: LysM domain-containing
GPI-anchored protein


3 LysM结构域蛋白是一类重要的植物
模式识别受体
高等真核生物先天免疫系统的主要功能之一是能够
区分微生物(“非我”)组分与宿主(“自我”)组分, 通
过宿主自身编码的PRRs识别微生物产生的PAMPs
(Nürnberger et al., 2004; Tanaka et al., 2013)。真菌
几丁质和脱乙酰壳多糖(常见于真菌和昆虫)能够诱导
植物免疫反应, 是典型的病原体相关分子模式(Ren
and West, 1992; Felix et al., 1993; Shibuya and
Minami, 2001; Iriti and Faoro, 2009; Hamel and
Beaudoin, 2010)。植物细胞中首个几丁质受体——几
丁质激发子结合蛋白(chitin elicitor binding protein,
CEBiP)是通过配体亲和纯化从水稻(Oryza sativa)中
克隆得到的(Felix et al., 1993; Kaku et al., 2006)。
OsCEBiP具有2个LysM结构域和1个跨膜域, 但缺乏
胞内激酶域, 表明OsCEBiP实现信号跨膜传递需要
有其它组分或共同受体(Kaku et al., 2006)。在此基础
上, 拟南芥中第1个几丁质受体也很快被鉴定, 并命
名为CERK1 (chitin elicitor receptor kinase 1), 该蛋
白具有典型的受体激酶结构, 包括3个胞外LysM结构
域、1个跨膜域及1个胞内激酶域; cerk1突变体中壳聚
糖诱导的活性氧爆发和MAPK级联反应几乎完全消
失, 但对脂多糖(lipopolysaccharide)的响应没有明显
变化, 说明CERK1对几丁质的识别具特异性(Miya et
al., 2007)。
随后, 水稻几丁质信号转导所需要的另一个信号
组分OsCERK1也被成功鉴定。OsCERK1编码的蛋白
仅含有1个LysM结构域, 与AtCERK1的第3个LysM
结构域序列相似性最高; 而OsCERK1沉默的水稻植
季东超等: LysM蛋白介导植物免疫防卫反应及其信号激发的研究进展 631

株表现出与CEBiP沉默植株类似的表型, 对几丁质诱
导几乎无响应(Shimizu et al., 2010)。体外互作实验
结果表明, OsCERK1能够与OsCEBiP互作, 但不具
直接结合壳聚糖的能力。因此, 研究者推测OsCEBiP
和OsCERK1异源二聚体受体复合物的形成是实现几
丁质信号跨膜传递的前提条件 (Shimizu et al.,
2010)。与上述情况不同, 拟南芥AtCERK1能够独立
实现对几丁质信号的感知与传递, 但其胞外域的3个
LysM结构域对于其与几丁质的结合都不可缺少, 并
且胞外LysM结构与几丁质结合能够诱导CERK1同源
二聚体的形成, 从而保证胞内激酶域的相互磷酸化
(Petutschnig et al., 2010; Shiya et al., 2012)。周俭
民和柴继杰研究组合作解析了AtCERK1胞外域的晶
体结构, 为揭示其作用机制提供了有力证据: AtCER-
K1所含的3个LysM结构域的任何一个缺失都将破坏
其空间结构的稳定性, 但在该晶体结构中, 仅在第2
个LysM结构域检测到了与壳聚糖的结合, 这种特异
性还有待进一步研究(Liu et al., 2012b)。Shibuya领
导的研究小组综合运用生物化学、核磁共振和计算生
物学方法, 对水稻CEBiP受体复合物的形成和激活过
程进行了分析。结果发现, 壳聚糖分子能够在体外诱
导CEBiP分子的胞外域二聚化。据此, 他们提出了一
个新的作用模型, 即2个CEBiP分子同时反向结合在
1个壳聚糖分子上, 其中位于中间的lysin motif中的
Ile122对于该作用模式的维持至关重要(Hayafune et
al., 2014)。拟南芥和水稻中几丁质信号转导的受体复
合物及可能的信号激发机制见图1。
研究显示, 在拟南芥基因组5个含LysM结构域的
受体类激酶(LysM-containing receptor-like kinase,
LYK)中, 除了CERK1对几丁质响应是必需的, LYK4
在几丁质响应过程中也具一定的作用, 但其响应强度
较弱, 表现为lyk4突变体的感病性增强, 下游响应基
因表达受到明显抑制(Wan et al., 2012)。最初的研究
表明, 拟南芥中的3个CEBiP-like基因(AtLyM1、



图1 拟南芥和水稻中CERK1受体复合物及可能的信号激发机制(改自Macho and Zipfel, 2014)
(A) 几丁质诱导AtCERK1同源二聚化和激活, 在此过程中BIK1对于NADPH氧化酶产生活性氧爆发是必需的; (B) 水稻中的几丁质
受体复合物由OsCEBiP、OsCERK1和一些相关的胞质蛋白组成; 受几丁质刺激后, OsCERK1磷酸化OsRLCK185, 后者从受体复合
物上解离下来并参与下游信号转导; 另外, OsCERK1激活OsRacGEF1/OsRac1, 从而引起活性氧爆发。CERK1: 几丁质激发子受
体激酶; CEBiP: 几丁质激发子结合蛋白; BIK1: 葡萄胞属诱导激酶1; GEF1: 鸟嘌呤交换因子1; RLCK185: 细胞质类受体激酶185

Figure 1 CERK1 receptor complexes and signaling mechanism in Arabidopsis and rice (modified from Macho and Zipfel, 2014)
(A) Chitin induces AtCERK1 homo-dimerization and activation, while BIK1 is required for subsequent reactive oxygen species
burst from NADPH oxidase (RBOHD) during this process; (B) The chitin receptor complex is composed of OsCEBiP, OsCERK1
and several associated cytoplasmic proteins in rice; Upon stimuli from chitin, OsCERK1 phosphorylates OsRLCK185, which is
released from the receptor complex and contributes to down-streaming signal transduction; Additionally, OsCERK1 activates the
OsRacGEF1/OsRac1, which contributes to chitin-induced ROS burst. CERK1: Chitin elicitor receptor kinase1; CEBiP: Chitin
elicitor binding protein; BIK1: Botrytis-induced kinase1; GEF1: Guanine exchange factor1; RLCK185: Receptor-like cytoplasmic
kinase185

632 植物学报 50(5) 2015

AtLyM2和AtLyM3)突变体和过表达植株对几丁质的
响应均未表现出明显的差异(Shiya et al., 2012; Wan
et al., 2012)。然而, 拟南芥 lym1与 lym3突变体对
PGN的响应显著减弱, 细菌感病性显著增强, 而且
AtLyM1和AtLyM3能够与PGN直接互作 , 拟南芥
cerk1突变体对细菌病害的免疫能力也显著下降。由
此推测, 拟南芥PGN信号感知机制可能需要双信号
或多信号组分的参与(Willmann et al., 2011; Wan et
al., 2012)。此外, Faulkner等(2013)发现几丁质诱导
后AtLYM2介导了细胞间通过胞间连丝传递的分子流
(molecular flux)的弱化, 且此过程不依赖于AtCER-
K1。因此, 拟南芥中几丁质激活的免疫应答至少包括
2条相互独立的途径(Faulkner et al., 2013; Tanaka
et al., 2013)。Liu等(2012a)研究表明, 水稻OsLYP4
和OsLYP6也能够与PGN及几丁质结合, 且转基因植
株的感病性与OsLYP4和OsLYP6基因的表达水平呈
正相关。
4 LysM结构域蛋白识别病原体相关分
子模式后的下游信号传递
目前, 我们对LysM结构域蛋白识别病原体相关分子
模式后的下游信号传递过程还知之甚少。与以往关于
鞭毛蛋白受体FLS2和延伸因子受体EFR的研究结果
类似 , 拟南芥受体类胞质激酶 (receptor-like cyto-
plasmic kinases, RLCKs) BIK1可能与AtCERK1相互
作用。几丁质诱导后, bik1突变体中H2O2产生且胼胝
质积累显著下降, 而几丁质预处理后对突变体与野生
型植株进行病原菌接种, 突变体感病性明显增强。然
而, PBL1对几丁质诱导的胼胝质积累具有显著影响,
但对H2O2生成却没有明显作用(Zhang et al., 2010)。
上述结果表明, BIK1和PBL1都可能作为AtCERK1信
号跨膜传递之后的磷酸化底物, 将几丁质信号继续向
下游传递。最近的一项研究表明, 拟南芥中的一个
OsRLCK185同源物PBL27作为CERK1的直接下游
组分, 参与调节拟南芥中几丁质诱导的免疫过程。
CERK1在体外能够使PBL27磷酸化, 而BAK1却仅能
维持PBL27处于较低的磷酸化水平, 因此, 可以认为
CERK1和BAK1的底物选择特异性可能决定了下游
RLCKs的选择性激活(Shinya et al., 2014)。
几丁质触发的防御反应还涉及蛋白翻译后水平
的调节(Felix et al., 1993; Zhang et al., 2002)。丝裂
原活化蛋白激酶(MAPK)级联反应是信号传递网络中
的重要途径(Tena et al., 2011)。通常, 典型的MAPK
级联反应由蛋白激酶MAPKKK-MAPKK-MAPK组成,
通过顺序磷酸化将信号向下游传递(Ichimura et al.,
2002)。Wan等(2004)发现几丁质能够激活拟南芥
MPK3/MPK6的激酶活性, 而MPK3/MPK6能够调节
WRKY22/WRKY29的转录活性, 从而诱导下游防卫
基因的表达。MEKK1-MKK4/MKK5-MPK3/MPK6是
植物PTI信号转导中最为保守的途径, 过表达ΔME-
KK1和MKK4a/MKK5a可增强拟南芥对病原菌的抗性
(Asai et al., 2002)。相关研究表明, OsCERK1能够通
过其跨膜域与Hsp90、Hop/Sti1和小G蛋白Rac1直接
相互作用(Ono et al., 2001; Chen et al., 2010), Rac1
则通过MAPK级联反应启动信号向下传递(Lieberherr
et al., 2005; Kim et al., 2012; Yamaguchi et al.,
2013)。另外, 用几丁质激发子处理水稻悬浮细胞后,
非特异性磷酸酶C和磷酸酶D活性迅速上升 , 暗
示细胞质膜中磷脂信号分子对细胞膜透性的调节可
能也是一个很重要的调节因子(Yamaguchi et al.,
2005)。
5 病原菌对LysM结构域蛋白触发免疫
反应的规避机制
在与植物漫长的协同进化过程中, 病原菌逐渐进化出
能够抑制PTI过程的众多效应因子。研究表明, 丁香
假单胞菌等细菌能够通过AvrPto和AvrPtoB等效应蛋
白对模式识别受体进行修饰, 或直接泛素化并降解
PRR来抑制植物的免疫应答。目前, 关于效应蛋白的
报道主要集中在专一性识别效应蛋白的R基因克隆,
而关于效应蛋白抑制PTI机制的报道很少(De Wit et
al., 2009; Dou and Zhou, 2012)。丁香假单胞菌Pseu-
domonas syringae的效应蛋白AvrPtoB能够直接使
CERK1和FLS2泛素化, 并通过26S蛋白酶体复合物
介导其降解 , 从而抑制植株的PTI反应 (Gimenezl-
banez et al., 2009)。而Cladosporium fulvum的效应
蛋白Avr4通过与病原菌细胞壁中的几丁质结合, 抑制
植物几丁质酶对几丁质的降解, 从而加速病菌的侵染
(van den Burg et al., 2006; van Esse et al., 2007)。完
全不同的是, 病原真菌Mycosphaerella graminicola
季东超等: LysM蛋白介导植物免疫防卫反应及其信号激发的研究进展 633

和Magnaporthe oryzae中的效应蛋白Ecp6也具有典
型的LysM结构域, 虽然它并不能抑制几丁质酶对几
丁质的降解, 但能够与几丁质降解产生的壳聚糖竞争
与PRR的结合, 从而抑制PTI过程(de Jonge et al.,
2010)。综上所述, 病原真菌往往通过含有LysM结构
域的效应因子借助不同的进攻策略抑制植物PTI过
程。
6 小结
LysM结构域蛋白介导的植物免疫途径激活是通过
对病原菌中含GlcNAc的聚糖识别而启动的, 这种
复杂的关系是植物和微生物在长期协同进化过程
中逐渐获得的。过去十余年的研究证明, LysM结构
域蛋白通过与其它信号组分互作形成信号复合体
(signalsome), 直接或间接识别来源于微生物的
“非我”结构。尽管LysM结构域蛋白介导植物免
疫途径激活的相关研究工作已经取得了显著进展,
但是LysM结构域对不同聚糖结构的特异性识别机
制并不十分清楚, LysM蛋白形成异源二聚体或多
聚体的能力以及胞外结构域中的溶解素基序的数
目对上述特异性识别的作用还有待深入研究。另
外, 质膜微区(membrane microdomain)在LysM结
构域蛋白介导的植物免疫途径激活过程中的功能
尚未见报道。可以预见, 进一步研究配体-受体结合
特异性的分子基础将为我们深入解析植物细胞免
疫规避机制提供新的信息。
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Studies of Innate Immunity Mediated by Lysin Motif Protein
and Its Signaling Priming
Dongchao Ji, Kai Song, Jingjing Xing, Tong Chen*, Shiping Tian
Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
Abstract Lysin motif (LysM) is a ubiquitous protein domain found in most living organisms. LysM-containing proteins in
plant cells can recognize different GlcNAc-containing ligands, thereby triggering specific defense responses to pathogens.
As a group of important pattern recognition receptors, LysM-containing proteins trigger downstream signaling by oli-
gomerization, thus interacting with the Botrytis-induced kinase 1 (BIK1) and mitogen-activated protein kinase (MAPK)
cascade. Pathogenic microorganisms also use certain mechanisms to escape from pathogen-associated molecular pat-
tern-triggered immunity by utilizing specific recognition or modification of pattern recognition receptors by the secreted
effector proteins. This review focuses on the functions of these receptor kinases/proteins in response to elicitor stimuli and
priming of defense responses.
Key words defense responses, immunity, Lysin motif, pathogenic bacteria
Ji DC, Song K, Xing JJ, Chen T, Tian SP (2015). Studies of innate immunity mediated by lysin motif protein and its
signaling priming. Chin Bull Bot 50, 628–636.
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* Author for correspondence. E-mail: chentong@ibcas.ac.cn
(责任编辑: 孙冬花)