Improvement in ozone tolerance of tobacco plants with an antisense DNA for 1‐aminocyclopropane‐1‐carboxylate synthase

Abstract

Abstract Antisense DNA for an ozone‐inducible 1‐aminocyclopropane‐1‐carboxylate (ACC) synthase (EC 4.4.1.14; LE‐ACS6) from tomato, under the control of the cauliflower mosaic virus 35S promoter, was introduced into tobacco to generate transgenic plants. Lower rates of ozone‐induced ethylene production were observed in three of seven transgenic plants than in the wild‐type plants. Ozone‐induced visible damage was attenuated in these three lines, and the extent of damage was positively related to the level of ozone‐induced ethylene production. In the most ozone‐resistant line, ozone‐induced accumulation of ACC and levels of transcripts for ozone‐inducible endogenous ACC synthases were suppressed compared with those in wild‐type plants, demonstrating that ozone‐inducible ACC synthases have a key role in the expression of leaf damage by ozone exposure. No significant differences in growth and morphology were observed between transgenic and wild‐type plants. Stomatal conductance of transgenic plants during ozone exposure was higher than that of wild‐type plants. These findings indicate that the introduction of antisense DNA for an ozone‐inducible ACC synthase can improve the ozone tolerance of plants without reducing their gas absorption and productivity.