The generation of superoxide(O2-) in incompatible and compatible combinations among nineteen rice (Oryza sativa L. ) cultlvars and eight Pyricularia oryzae races or their hyphal metabolites (RBHM) had been measured. The O2- generation was enhanced in incompatible combinations but not in compatible combinations. Digitonln could induce O2- generation increased rapidly in rice seedlings and accompanied by the increase of their resistance to the infection by compatible blast pathogen. Dethyldithiocarbamate (DDTC), the inhibitor of cooper-type superoxide dismutase (SOD), could induce O2- generation seriously. N-ethylmaleimide (NEM), the scavenger of O2-, could induce the increase of rice SOD activity. Actinomycin D and cycloheximide could also induce O2- generation accompanied by the inhibition of SOD activity. The activity of phenylalanine ammonia-lyase (PAL) could be induced stronger and faster in incompatible system than in compatible system. However, the inducible PAL activity seems to be no specific relationship to rice resistance to blast infection because it could be induced by many different chemicals including digitonin, DDTC and NEM. The activity of chitinase and β-1,3-glucanase could not be induced by DDTC, NEM and digitonin. Their activation seems no relationship to O2- generation, and the signal transduction pathway for induction of their expression may not be similar to the pathway for PAL activation.
Xiao Shuangsuo,Wang Jun. Relationship among Generation Rate of Superoxide, Resistance of Rice to Blast Fungi and Activation of Inducible Phenylalanine Ammonia-lyase, Chitinase,β-1,3-glucanase [J]. , 1997, 11(2): 93-102 .