Ozone-Induced Expression of Stress-Related Genes in Arabidopsis thaliana

Abstract

Ozone is a major gaseous pollutant that is known to have detrimental effects on plant growth and metabolism. We have investigated the effects of ozone on Arabidopsis fhaliana growth and the pattern of expression of several stress-related genes. A. thaliana plants treated with either 150 or 300 parts per billion (ppb) ozone daily for 6 h exhibited reduced growth and leaf curling.Fresh and dry weights of ozone-treated plants were reduced 30 to 48% compared to ambient air controls. RNA blot analyses demonstrated that mRNA levels for glutathione S-transferase (CST), phenylalanine ammonia-lyase (PAL), a neutral peroxidase, and a cytosolic Cu/Zn superoxide dismutase (SOD) were higher in plants treated with 300 ppb ozone than in ambient air-treated controls.The mRNA levels of lipoxygenase and a catalase were not affeded by ozone treatment. Of the transcripts examined, CST mRNA levels increased the most, showing a 26-fold indudion 3 h after the initiation of ozone treatment. PAL mRNA was also rapidly induced, reaching 3-fold higher levels than controls within 3 h of ozone treatment. The neutral peroxidase and SOD mRNA levels rose more slowly, with both reaching maximum levels corresponding to 5-fold and 3-fold induction, respectively, approximately 12 h after ozone treatment. These studies indicate that ozone-induced expression of stress-related genes in A. fhaliana provides an excellent model system for investigating the molecular and genetic basis of ozone-induced responses in plants.

Senescence-Associated Gene Expression during Ozone-Induced Leaf Senescence in Arabidopsis1

“…O 3 -induced leaf yellowing in Arabidopsis was previously observed in older leaves exposed to O 3 continuously for 2 d (Kubo et al, 1995). Rosette growth was reduced and downward leaf curling was evident within 4 d of O 3 exposure, similar to results obtained by Sharma and Davis (1994) and Rao et al (1995). Leaf curling appeared to be an altered growth response and was not the result of dehydration, since the percent dry matter did not vary between treatments in an independent experiment (data not shown).…”

Superoxide Dismutase in Arabidopsis: An Eclectic Enzyme Family with Disparate Regulation and Protein Localization

“…Previous research showed that mRNA for cytosolic CSD1 is induced in response to ozone fumigation (Sharma and Davis, 1994;Conklin and Last, 1995). We confirmed this observation and extended it to show that the CSD1 protein is also rapidly induced in response to ozone (Fig.…”

“…10A). The mRNA had decreased 24 h after the start of the fumigation to a steady-state level that was elevated compared with unfumigated controls, similar to the results seen by Sharma and Davis (1994). Although stimulated by Figure 9.…”

“…Tissue was collected during the fumigation and recovery periods, and the levels of CSD1, CSD2, CSD3, FSD1, FSD2, and MSD1 mRNAs were assayed by RNA-blot hybridization, with the results shown in Figure 10A. As previously described (Sharma and Davis, 1994;Conklin and Last, 1995), CSD1 mRNA accumulation was induced by ozone fumigation and continued to increase during the beginning of the recovery period (Fig. 10A).…”

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterisation

“…It is not the first time that a delay in ozone triggering emissions has been reported. Sharma et al (1994) fumigated thaliana leaves and observed 3 h delay in the synthesis of phenylpropanoid compounds while Heiden at al. (1999) reported enhanced SQT concentrations 5 h after fumigating an ozone resistant variety of Nicotiana tabacum with 170 nmol mol −1 O 3 .…”