c‍itrus greening disease is the most important bacterial diseases of citrus and is present in the southern region of Iran. Due to the nature of the pathogen, disease control is difficult. cDNA-AFLP analysis shows that the expression pattern of NBS-LRR (Nucleotide Binding Site- Leucine-Rich Repeats) genes was upregulated in grapefruit plant interacting with Candidatus Leiberibacter aciaticus. In this study we have isolated the NBS552 gene from grapefruit by PCR and clone it by ligation of this product to pGEM-T vector transformed E. coli bacteria. Sequencing analysis revealed an open reading frame for a gene of 171 bp that encodes a protein of 57 amino acids. Results of bioinformatic analysis showed that this gene contains regions that are conserved in different plant species. The NBS552 protein is associated with membranes and its extracellular secretion is low. The aim of this study was isolation and cloning of NBS552 genes from the grapefruit genome and characterization of the genes in view of their potential for practical use in plants.