Angiosperm Flora of India

The OzT8 locus in rice protects leaf carbon assimilation rate and photosynthetic capacity under ozone stress

Publication Type:Journal Article
Year of Publication:2011
Journal:Plant, Cell & Environment
Date Published:2011
ISBN Number:1365-3040
Keywords:Oryza, Oryza sativa, photosynthesis, quantitative trait locus, stomatal response, tolerance

Tropospheric ozone (O3) is a phytotoxic air pollutant whose current background concentrations in parts of East Asia have caused estimated rice yield losses of up to 20%; currently, however, little is known about the mechanisms of O3 tolerance in rice. We previously identified a quantitative trait locus (QTL) in rice called OzT8, which was associated with relative dry weight under ozone stress. The photosynthetic response in SL46, a Nipponbare (NB)–Kasalath chromosome segment substitution line (SL) containing the OzT8 locus, was compared to the parent NB in multiple ozone fumigation experiments (100 ppb, 8 h d–1, 23 d). By day 23, SL46 showed significantly less reduction of photosynthetic capacity compared to NB; the maximum carboxylation rate of ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) decreased by 24% in SL46 compared to 49% in NB, and the maximum electron transport rate decreased by 16 and 39%, respectively. The midday carbon assimilation rates also showed a similar trend, but there was no genotypic difference in stomatal conductance. These results indicate that the OzT8 locus confers ozone tolerance via biochemical acclimation, not avoidance, making it a potentially valuable target for breeding of ozone tolerance into future rice lines. The sequence of photosynthetic response of rice to ozone stress and related tolerance factors are also discussed.

Short Title:Plant, Cell & Environment
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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith