In order to identify the possible protein targets of cyanide in the regulation of root hair, we have carried out a single cell proteomic approach to characterize the protein atlas in wild type root hair cells compared to the cas-c1 mutant cells. Root hair specific cells were obtained from isolated protoplast from root tissues of Arabidopsis wt-pCOBL9:GFP and cas-c1-pCOBL9:GFP lines. To analyze the effect of the CAS-C1 mutation, we isolated 1 x 106 root hair cells by Fluorescence-activated cell sorting (FACS) from three independent replicate of wt-pCOBL9:GFP and cas-c1-pCOBL9:GFP roots. The extracted proteins from each sample were trypsin-digested and the digested peptides were analyzed by liquid chromatography-high resolution mass spectrometry (LC-MS/MS) for protein identification. In wild type samples, we have identified 3829 unique proteins at a false discovery rate below 1% (FDR<1%), that represent almost 10% of the total Arabidopsis proteome. In protein extract of the cas-c1-pCOBL9:GFP roots samples, we have identified 3972 proteins of which 3515 were commons in both cell types, 310 were only identified y wild type and 457 only in cas-c1 mutant (Fig. 5).