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The OzT8 locus in rice protects leaf carbon assimilation rate and photosynthetic capacity under ozone stress
Author(s) -
CHEN CHARLES P.,
FREI MICHAEL,
WISSUWA MATTHIAS
Publication year - 2011
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02312.x
Subject(s) - photosynthesis , rubisco , ozone , stomatal conductance , photosynthetic capacity , acclimatization , horticulture , botany , biology , tropospheric ozone , canopy , dwarfing , chemistry , organic chemistry , rootstock
ABSTRACT Tropospheric ozone (O 3 ) 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 O 3 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.