拟南芥类受体蛋白激酶的激酶域信号传导强度研究

为了解不同类受体蛋白激酶RLKs激酶域响应病原相关分子PAMPs信号强度的差异,本研究将拟南芥FLS2的胞外域(NT)与6种不同RLKs的激酶域(KD)组合为重组RLKs(rRLKs),构建融合基因表达载体,并通过拟南芥原生质体瞬时表达的方法,将rRLKs/FLS2、35S::GUS(内参)和FRK1::Luciferase(响应报告载体)共转化到拟南芥fls2突变体叶肉原生质体细胞中;后经flg22处理后,通过对萤光素酶(Luciferase)和葡糖苷酸酶(GUS)活性的定量分析和比较,鉴定不同RLKs激酶区域信号传导的强度。结果表明:1)FLS2、EFR、PEPR1和RLK7的激酶域可明显激活抗病响应报告基因FRK1的表达,对植物抗病反应起正调控作用;FLS2和EFR的激酶域信号传导能力最强,两者无显著差异(P0.05);PEPR1和RLK7激酶域的信号传导能力稍弱,其信号传导强度分别是FLS2的57.13%和32.92%,与FLS2差异显著(P0.05);2)CERK1和NIK1的激酶域对FRK1的上调作用不明显,其信号传导强度分别仅有FLS2的9.76%和7.88%,和FLS2NT(对照)之间无显著差异(P0.05);3)PSKR1激酶域引起FRK1表达下调,对PTI起负调控作用。本研究结果有助于了解RLK家族的抗病响应作用机理,并为人工构建更高效的rRLK蛋白提供参考。

Different kinase domains of Arabidopsis receptor like protein kinases generate various signaling output profiles

The aim of this study was to investigate and compare the signaling strength of kinase domains (KD) of the receptor-like kinase family (RLK) in responding to pathogen-associated molecular patterns (PAMP).Recombinant RLKs (rRLKs) with extracellular domain of FLS2 and cytoplasmic kinase domain of several RLKs in Arabidopsis were constructed.A total of six rRLKs and FLS2 transient expression vectors were constructed in this study and transformed to Arabidopsis protoplast with 35S::GUS (internal reference) and FRK1::Luciferase (PTI reporter gene vector).After flg22 treatment,the activity of Luciferase and GUS was determined for analyzing the signaling transduction strength of different kinase domain of RLKs.The results showed that:1) The kinase domains of FLS2,EFR,PEPR1 and RLK7 obviously activated the expression of PTI reporter gene FRK1,which played a positive regulatory roles for plant disease resistance;FLS2 KD and EFR KD generated higher signaling output,and there was no significant difference between their signaling transduction intensity (P<0.05);PEPR1 KD and RLK7 KD generated weaker signaling output than that of FLS2 KD and EFR KD,which were respectively 57.13% and 32.92% of FLS2 KD and showed significant difference with FLS2 KD (P<0.05);2) The activation effects of CERK1 KD and NIK1 KD on FRK1 were not obvious,and their signaling transduction intensities were only 9.76% and 7.88% of FLS2 KD,respectively.There was no significant difference with FLS2 NT (Control) (P<0.05);3) However,PSKR1 KD down-regulate FRK1 expression,played a negative regulatory role in PTI.In conclusion,this study provided references for understanding the working mechanisms of PRRs and foundation for creating high efficient rRLK.