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Environmentally driven evolution of R ubisco and improved photosynthesis and growth within the C 3 genus L imonium ( P lumbaginaceae)
Author(s) -
Galmés Jeroni,
Andralojc P. John,
Kapralov Maxim V.,
Flexas Jaume,
Keys Alfred J.,
Molins Arántzazu,
Parry Martin A. J.,
Conesa Miquel À.
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12858
Subject(s) - rubisco , photosynthesis , carboxylation , biology , botany , pyruvate carboxylase , oxygenase , biochemistry , chemistry , enzyme , catalysis
Summary Carbon assimilation by most ecosystems requires ribulose‐1,5‐bisphosphate carboxylase/oxygenase ( R ubisco). Its kinetic parameters are likely to have evolved in parallel with intracellular CO 2 availability, with the result that faster forms of R ubisco occur in species with CO 2 ‐concentrating mechanisms. The R ubisco catalytic properties were determined and evaluated in relation to growth and carbon assimilation capacity in M editerranean L imonium species, inhabiting severe stress environments. Significant kinetic differences between closely related species depended on two amino acid substitutions at functionally important residues 309 and 328 within the R ubisco large subunit. The R ubisco of species facing the largest CO 2 restrictions during drought had relatively high affinity for CO 2 (low Michaelis–Menten constant for CO 2 ( K c )) but low maximum rates of carboxylation ( k cat c ), while the opposite was found for species that maintained higher CO 2 concentrations under similar conditions. Rubisco kinetic characteristics were correlated with photosynthetic rate in both well‐watered and drought‐stressed plants. Moreover, the drought‐mediated decrease in plant biomass accumulation was consistently lower in species with higher R ubisco carboxylase catalytic efficiency ( k cat c / K c ). The present study is the first demonstration of R ubisco adaptation during species diversification within closely related C 3 plants, revealing a direct relationship between R ubisco molecular evolution and the biomass accumulation of closely related species subjected to unfavourable conditions.