Selection strategy for damping-off resistance gene by biotechnology in rice plant

Aims: The gradual decline in rice yield is a trend closely related to the occurrence of various pathogens, especially Pythium graminicola and Rhizoctonia solani; these are major soil-borne pathogens that cause the plant disease damping-off, which seriously damages seed germination and growth worldwide. Methods: After treatment with P. graminicola and Rhophitulus solani in 120 Cheongcheong/Nagdong double haploid (CNDH) populations, they were divided into a resistant group and a susceptible group, and finally the damping-off resistance gene was mapped using the genotype and phenotype. And then, the expression level of OsDGTq1 screened was analyzed. Results: Using the genotypes/phenotypes of the 120 CNDH populations, loci that induced resistance to P. graminicola and R. solani were detected simultaneously in RM11849-RM212 on chromosome 1 and RM27242-RM2698 on chromosome 11. In these areas, open reading frames related to the cell wall, cell death, signaling, and secondary metabolites affecting plant defense were searched. The relative expression levels of these open reading frames were analyzed after P. graminicola and R. solani inoculation; OsDGTq1 expression increased sharply in the resistance population relative to the susceptible population at the initial stage after pathogen inoculation. Conclusions: These results suggest that OsDGTq1 reacts rapidly to the initial stage of inoculation when pathogens attack and is involved in cell wall synthesis, which induces systemic acquired resistance. Hence, OsDGTq1 could potentially be used to develop damping-off resistant rice cultivars that improve yield at the early stages of rice growth.