Genome editing of elite rice cultivar, CO51 for bacterial leaf blight resistance

Abstract

Bacterial leaf blight (BLB) of rice caused by Xanthomonas oryzae pv oryzae (Xoo) is a major constraint in rice production. Natural resistance to BLB in some of the wild type cultivars of rice is due to mutations in effector binding element (EBE), present in the promoter region of SWEET genes. SWEET14 is one of the most commonly targeted genes by majority of the TALEs of Xoo pathogen. Thus, the present study was aimed at creating novel mutations in the EBE of OsSWEET14 gene in indica rice cultivar, CO51 through CRISPR/Cas9 mediated genome editing technology to impart resistance against BLB. Agrobacterium-mediated transformation using immature embryos followed by regeneration resulted in eleven transgenic plants from six independent transformation events, of which nine plants (belonging to five events) had mutations in the target sequence. Bioassay studies on four mutant plants (belonging to three events) resulted in the identification of two plants (belonging to two events) with resistance/moderately resistance against BLB. Key words: Rice, SWEET genes, CRISPR/Cas9, Bacterial Leaf Blight, Effector Binding Element