Journal
PLANT PHYSIOLOGY
Volume 163, Issue 1, Pages 75-85Publisher
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.113.223420
Keywords
-
Categories
Funding
- Comision Interministerial de Ciencia y Tecnologia
- European Union-FEDER [BIO2009-07040]
- Junta de Andalucia [P07-CVI-02795, P09-CVI-4704]
- Spanish Ministry of Education (Formacion de Personal Universitario grant)
Ask authors/readers for more resources
STARCH SYNTHASE4 (SS4) is required for proper starch granule initiation in Arabidopsis (Arabidopsis thaliana), although SS3 can partially replace its function. Unlike other starch-deficient mutants, ss4 and ss3/ss4 mutants grow poorly even under long-day conditions. They have less chlorophyll and carotenoids than the wild type and lower maximal rates of photosynthesis. There is evidence of photooxidative damage of the photosynthetic apparatus in the mutants from chlorophyll a fluorescence parameters and their high levels of malondialdehyde. Metabolite profiling revealed that ss3/ss4 accumulates over 170 times more ADP-glucose (Glc) than wild-type plants. Restricting ADP-Glc synthesis, by introducing mutations in the plastidial phosphoglucomutase (pgm1) or the small subunit of ADP-Glc pyrophosphorylase (aps1), largely restored photosynthetic capacity and growth in pgm1/ss3/ss4 and aps1/ss3/ss4 triple mutants. It is proposed that the accumulation of ADP-Glc in the ss3/ss4 mutant sequesters a large part of the plastidial pools of adenine nucleotides, which limits photophosphorylation, leading to photooxidative stress, causing the chlorotic and stunted growth phenotypes of the plants.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available