Study On AHLs-perception Site On The Plasma Membrane Of Plant Celland Functinalof Cam Inahl-modulated Plant Growth

Many bacteria use small signal molecules to communicate with each other and tocoordinate their collective behavior-a process commonly referred to as quorum sensing(QS). The most common QS signals are N-acyl-homoserine lactones (AHLs). AHL cansignificantly promote the growth of roots and induce the resistance response to response tereduce the chance of infected by pathogens in plant. For this reason, AHLs may be a newplant immune activator and its transduction mechanism in plant cells become hot issue inresent years. However, its transduction net is complex and multiple. We mainly study thefollowing two parts using Arabidopsis thaliana as material.The study of plant cell inducting bacteria N-acyl homoserine lactones(AHL). We usedbiotinylated3OC6-HSL (BioOC6) to characterize the AHL-perception sites in theprotoplast of Arabidopsis thaliana.The AHL-perception sites were visualized byfluorescence microscopy and confocal laser scanning microscopy (CLSM), using bioABAand fluorescence-labeled avidin. Fluorescent particles were observed in patches on thesurface of the protoplast. Fluorescence intensity was quantified by fluorescence microscopyas well as by CLSM. Binding of bioABA was inhibited by ABA in a dose-dependentmanner. We suspected theAHL recptors may be a membrane receptor.Involvement of Calmodulin (CaM) of Arabidopsis root growth by N-acylhomoserinelactones. This reserch mainly demonstrated it from four aspects that is pharmacology,genetics, gene expression and protein level. At the unsensitivce concentration, W7, theantagonist of CaM, can eliminate the promoting to root growth by3OC6-HSL. Differingfrom the wild plant, the promoting to root growth by3OC6-HSL disappear on thecam4/cam5/cam6/cam7/cam9, even it turns to inhibition on the cam1/cam2/cam3/cam8,the promoting to root growth by3OC8-HSL disappear on the cam1/cam3/cam4/cam5/cam6/cam7/cam8, even it turns to inhibition on the cam2/cam234/cam9. What’s more,AHLs can significantly up-regulated cam1-cam9/camp. In addition, using Western Blot andElisa to detcet the CaM express quantity after3OC6-HSL effected the wid plant at differenttime.As a conclusion, CaM involved in the signaling transduction byAHLs in plants.