百脉根LysM型受体LcLRK1参与菌根真菌丛枝形成

Lys M receptor LcLRK1 from Lotus corniculatus involved in the arbuscule formation

从日本百脉根(Lotus corniculatus)中克隆到一个可能与菌根因子识别相关的Lc LRK1基因,通过设计简并引物并利用RACE PCR手段,在百脉根中扩增得到Lc LRK1基因全长序列。通过生物信息学的方法,对Lc LRK1基因进行结构分析和预测;接种Rhizophagus irregularis,检测Lc LRK1基因在百脉根不同组织中的表达水平;构建Pro Lc LRK1∶∶GUS重组载体,观察Lc LRK1基因在根中的表达部位;最后通过RNA干扰(RNAi)技术进行Lc LRK1基因沉默。结果表明:Lc LRK1编码一个Lys M型受体激酶,由3个胞外Lys M结构、1个跨膜结构域与1个胞内激酶结构域组成;Lc LRK1在AM共生早期表达水平明显增强,并在根的表皮细胞及根毛基部表达;Lc LRK1基因沉默后抑制了早期丛枝的形成;相对于对照组,在Lc LRK1RNAi的植株中AM真菌的侵染率明显下降,丛枝数目也明显降低。证实Lc LRK1基因与菌根真菌信号分子识别相关,并且影响AM真菌丛枝的形成。

A LysM receptor LcLRK 1 gene possibly involved in Myc-factor perception was isolated from Lotus corniculatus. The full-length of LcLRK1 gene was isolated from L. corniculatus by using the degenerate primers and RACE PCR strategies. The structure of LcLRK1 gene was analyzed with bioinformatics.The expression profiles of LcLRK 1 gene were investigated in variant tissues from L. cor- niculatus after inoculation RhizoDhagus irregularis. A recombinant plasmid harboring ProLcLRK 1 ： ： GUS reporter was constucted to localize LcLRK 1 in the roots of L.corniculatus.The LcLRK 1 gene was knock-down with RNA interference.The results showed that LcLRK 1 gene, encoding a LysM receptor kinase,was comprised of three extracellular LysM domains, a transmembrane domain and intracellular kinase domain.LcLRK1 gene was up-regulated in roots at early stage of AM symbiosis and the tran- scripts of LcLRK1 were mainly present in the root epidemis and root hairs. The knock-down of the LcLRK 1 gene significantly decreased AM fungal colonization. In RNAi lines, the infection rate and arbus- cule numbers were strongly reduced compared to that in the controls.The LcLRK 1 gene may participate in the perception of Myc-factor and down-regulation of LcLRK 1, affecting the formation of AM fungal arbuscule.