Abstract
We have analyzed ozone (O3) tolerance in two Arabidopsis ecotypes: Col (O3-tolerance) and Ws (O3-sensitive). An approach of QTL mapping in RI lines had performed to detect O3-sensitive loci. Two main QTLs were identified, one is located chr.4 and the other is chr.5. The former locus was located near (AtACS6) gene that involve in ethylene biosynthesis. The (AtACS6) expression and ethylene evolution in Ws was higher than in Col. Comparison of entire sequence of (AtACS6) genome showed that Ws has 13bp extra sequence in its promoter region. To know function of the extra sequence for (AtACS6) expression, we made two transgenic plants; one was excluded the extra sequence from Ws promoter and the other was inserted the extra sequence into Col promoter. Expression levels of (AtACS6) depend on presence of the extra sequence, suggesting that this sequence involve in O3-induced ethylene production level and determines part of O3-sensitivity in Ws.
