Citrus canker caused by the bacterium Xanthomonas citri subsp. citri (Xcc) causes significant damages to the citrus fruit industry on a global scale. A team of Chinese scientists with Xiuping Zou as corresponding author and Aihong Peng and Shanchun Chen as leading authors from the Citrus Research Institute at the Chinese Academy of Agricultural Sciences and Southwest University of China offers an alternative to the traditional breeding methods for development of resistant citrus varieties by using the CRISPR/Cas9 genome editing technology. The function of the LATERAL ORGAN BANDARDS 1 gene (CsLOB1) is essential for the development of the disease. The genome of Citrus sinensis Osbeck has at least 3 copies of the CsLOB1G allele and one copy of the CsLOB1– allele. The promoter region of the gene in both alleles contains EBEPthA effector binding element, which was a subject of modification within the study. As a result of the experiments conducted, sixteen lines containing modifications of this region were developed as in four of them (S2-5, S2-6, S2-12 and S5-13) an increased resistance to the disease compared to the wild type was observed. Even more, in two of the lines (S2-6 and S5-13) no symptoms of the disease were detected. The results of the study, which were recently published in the Plant Biotechnology Journal, show that editing of the CsLOB1 promoter region using CRISPR/Cas9 technology can be successfully used for development of varieties resistant to citrus canker.
Source: Crop Biotech Update
Peng, A., Chen, S., Lei, T., Xu, L., He, Y., Wu, L., Yao, L. and Zou, X. (2017) Engineering canker-resistant plants through CRISPR/Cas9-targeted editing of the susceptibility gene CsLOB1 promoter in citrus. Plant Biotechnol. J., https://doi.org/10.1111/pbi.12733