Abstract
Jasmonic acid (JA) plays an important role as a signaling molecule in plant defense responses to wound stress and pathogen infection. Although there are various JA-inducible pathogenesis-related (PR) genes in rice, JA does not enhance the disease resistance against rice blast fungus Magnaporthe grisea. To resolve this discrepancy, we generated and analyzed JA-deficient rice plants (F7Ri) with co-suppression of both two intrinsic plastidial ω-3 fatty acid desaturases, OsFAD7-1 and OsFAD7-2, that supply the JA precursor linolenic acid. Unexpectedly, in F7Ri plants, the disease resistance against M. grisea was enhanced in a non-race-specific manner. Furthermore, the enhanced resistance in F7Ri was not restored by the methyl-jasmonate treatment. These results suggest that JA is not an effective regulator of the fungal resistance. Moreover, this study provides a novel insight that the oxidized derivatives of polyunsatulated fatty acids may be involved in rice-specific fungal resistance.
