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Title: ALTERATION OF THE REGULATION OF RUBISCO VIA RUBISCO ACIVASE

Author
item PORTIS JR, ARCHIE
item ZHANG, NING - CROP SCIENCES UOFI URBANA
item EWY, ROBERT
item KALLIS, RUSSELL - CROP SCIENCES UOFI URBANA

Submitted to: Photosynthesis International Congress Symposium Proceedings and Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The Arabidopsis rca-minus mutant, which does not express either of the two isoforms of activase, was transformed with CDNA's encoding activase to obtain plants that express only one form of activase. Light activation of Rubisco was restored but light modulation of Rubisco activity was eliminated in plants expressing only the smaller isoform and in plants expressing the larger isoform in which the cysteine residues located in the c-terminal domain unique to the larger isoform were replaced by alanine. Thus plants expressing only the shorter form of activase with glutamine or aspartate substitution at position 111, which alters the ADP/ATP response in vitro, were also no longer light modulated. However, introduction of an unmodified larger isoform by genetically crossing these lines with plants expressing only the larger isoform largely restored light modulation. These plants may be suitable for future studies of the role of ADP/ATP regulation in the response of Rubisco to sink limitations.