Targeted editing of OsSWEET13, a bacterial leaf blight susceptible gene in rice using CRISPR tool
Bacterial leaf blight (BLB) of rice is considered to be a disease of economic importance as the disease causes severe yield losses in all rice growing regions. Transcription activator like effector (TALE) molecules are produced by the pathogen, Xanthomonas oryzae pv. oryzae (Xoo) bind to the effector binding element (EBE) of the promoter of SWEET gene and activates transcription of SWEET genes, making the plant susceptible to the disease. Innate resistance to Xoo in certain rice genotypes is due to mutations in EBE present in the upstream regulatory region of SWEET genes. CRISPR–mediated targeted modification of susceptibility gene/promoter is an effective approach to develop BLB resistance in rice. The present study was an attempt to repress TALE triggered signalling via introducing indels in the EBE of OsSWEET13 gene in a local popular rice genotype, CO51 employing CRISPR/Cas9 mediated genome editing tool with a view to imparting BLB resistance. Agrobacterium-mediated transformation using immature embryos followed by regeneration resulted in four independent transformation events. Five plants representing three events were found to have one nucleotide deletion in the target sequence. These deletion mutations in EBE could potentially interfere with the binding of the corresponding TALE to confer resistance against certain strains of BLB.
Keywords: Rice, Bacterial Leaf Blight, SWEET13 gene, Effector Binding Element, CRISPR/Cas9.
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