Potential marker proteins for ozone-induced yield reduction in rice

Three proteins - a 60-kDa chaperonin (CPN-60), chloroplastic ATP synthase, and enolase 1 - were evaluated as potential markers of ozone-induced yield responses in six rice (Oryza sativa L.) cultivars ('Kirara 397', 'Koshihikari', 'Nipponbare', 'Takanari', 'Kasalath', 'Suphanburi 90') under ozone stress in laboratory-scale tests. The levels of all three proteins decreased after ozone exposure in cultivars identified as ozone-sensitive while they increased or remained constant after ozone exposure in tolerant cultivars, although ATP synthase tended to decrease. Furthermore, the protein level and grain yield in each cultivar exposed to ozone were significantly positively correlated for all three proteins. Thus, CPN-60 and enolase 1 are potential markers for chronic ozone stress in rice.