Overexpression of Glycosyl Hydrolase Gene Through Activation Tagging Enhances Sheath Blight Tolerance in Rice (Oryza Sativa L.)

Abstract Background Activation tagging is an efficient gain-of-function approach to create novel phenotypes and to identify their underlying genes. In this study, a mutant population was developed in the recalcitrant indica rice (Oryza sativa L.) cv. BPT 5204 (Samba Mahsuri) through activation tagging using Ac-Ds transposons. Methods and results From the mutant population, 38 (Ac−Ds+ plants) stable Ds plants were generated through germinal transposition at T2 generation. Based on phenotypic evaluation and preliminary screening for sheath blight (ShB) resistance caused by fungal pathogen Rhizoctonia solani (R. solani), five stable activation tagged Ds lines (M-Ds-1, M-Ds-2, M-Ds-3, M-Ds-4 and M-Ds-5) were selected. Among them, M-Ds-3 and M-Ds-5 lines showed significant resistance for ShB over other tagged lines and wild type (WT) plants. Furthermore, flanking sequence and gene expression analysis revealed that the upregulation of glycoside hydrolase-OsGH or similar to Class III chitinase homologue (LOC_Os08g40680) in M-Ds-3 and a hypothetical protein gene (LOC_Os01g55000) in M-Ds-5. Conclusion Over-expression of glycoside hydrolase gene through activation tagging is demonstrated to be involved in ShB resistance Our study is the first to use Ac-Ds based gain-of-functional mutation to report candidate genes associated with ShB resistance in rice.