拟南芥
鲁比斯科
烟草
拟南芥
生物
生物化学
光合作用
基因
突变体
作者
Elizabete Carmo‐Silva,Michael E. Salvucci
出处
期刊:Plant Physiology
[Oxford University Press]
日期:2013-02-15
卷期号:161 (4): 1645-1655
被引量:173
标识
DOI:10.1104/pp.112.213348
摘要
Abstract Rubisco’s catalytic chaperone, Rubisco activase (Rca), uses the energy from ATP hydrolysis to restore catalytic competence to Rubisco. In Arabidopsis (Arabidopsis thaliana), inhibition of Rca activity by ADP is fine tuned by redox regulation of the α-isoform. To elucidate the mechanism for Rca regulation in species containing only the redox-insensitive β-isoform, the response of activity to ADP was characterized for different Rca forms. When assayed in leaf extracts, Rubisco activation was significantly inhibited by physiological ratios of ADP to ATP in species containing both α-Rca and β-Rca (Arabidopsis and camelina [Camelina sativa]) or just the β-Rca (tobacco [Nicotiana tabacum]). However, Rca activity was insensitive to ADP inhibition in an Arabidopsis transformant, rwt43, which expresses only Arabidopsis β-Rca, although not in a transformant of Arabidopsis that expresses a tobacco-like β-Rca. ATP hydrolysis by recombinant Arabidopsis β-Rca was much less sensitive to inhibition by ADP than recombinant tobacco β-Rca. Mutation of 17 amino acids in the tobacco β-Rca to the corresponding Arabidopsis residues reduced ADP sensitivity. In planta, Rubisco deactivated at low irradiance except in the Arabidopsis rwt43 transformant containing an ADP-insensitive Rca. Induction of CO2 assimilation after transition from low to high irradiance was much more rapid in the rwt43 transformant compared with plants containing ADP-sensitive Rca forms. The faster rate of photosynthetic induction and a greater enhancement of growth under a fluctuating light regime by the rwt43 transformant compared with wild-type Arabidopsis suggests that manipulation of Rca regulation might provide a strategy for enhancing photosynthetic performance in certain variable light environments.
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