Ce. Espineda et al., The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana, P NAS US, 96(18), 1999, pp. 10507-10511
Citations number
42
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Chlorophyll b is synthesized from chlorophyll a and is found in the light-h
arvesting complexes of prochlorophytes, green algae, and both nonvascular a
nd vascular plants. We have used conserved motifs from the chlorophyll a ox
ygenase (CAO) gene from Chlamydomonas reinhardtii to isolate a homologue fr
om Arabidopsis thaliana. This gene, AtCAO, is mutated in both leaky and nul
l chlorinal alleles, and DNA sequence changes cosegregate with the mutant p
henotype. AtCAO mRNA levels are higher in three different mutants that have
reduced levels of chlorophyll b, suggesting that plants that do not have s
ufficient chlorophyll b up-regulate AtCAO gene expression. Additionally, At
CAO mRNA levels decrease in plants that are grown under dimlight conditions
. We have also found that the six major Lhcb proteins do not accumulate in
the null ch1-3 allele.