Reference "Molecular evolution of phosphoenolpyruvate carboxylase for C4 photosynthesis in maize: comparison of its cDNA sequence with a newly isolated cDNA encoding an isozyme involved in the anaplerotic function"

Reference ID

7127

Title

Molecular evolution of phosphoenolpyruvate carboxylase for C4 photosynthesis in maize: comparison of its cDNA sequence with a newly isolated cDNA encoding an isozyme involved in the anaplerotic function

Source

Journal of biochemistry, 1992, vol. 112, pp. 147-154

Authors (6)

Kawamura-T	Shigesada-K
Toh-H	Okumura-S
Yanagisawa-S	Izui-K

Abstract

Molecular events associated with the evolution of an enzyme for C4
photosynthesis were investigated. In maize, at least three isozymes of
phosphoenolpyruvate carboxylase [EC 4.1.1.31] are known: the C4-form, the C2-
form and the root-form, being named according to their physiological roles and
pattern of tissue distribution [Ting, I.P. & Osmond, C.B. (1973) Plant
Physiol. 51, 448-453]. A cDNA clone which presumably encodes the C3-form
isozyme was newly isolated and analyzed. Comparison of the sequences of the
C3-form and C4-form isozymes revealed that (i) the homologies in the
nucleotide and deduced amino acid sequences were 71 and 77%, respectively, and
(ii) the gene for the C4-form isozyme evolved under strong G/C pressure. The
genes for these isozymes were found to be located apart on different
chromosomes. A phylogenetic tree was constructed using 8 amino acid sequences
of phosphoenolpyruvate carboxylases from various sources. The topology of the
tree indicated that, at least in monocots such as maize and sorghum, the genes
for the C4-form and C3-form isozymes diverged from their common ancestral gene
earlier than the monocot-dicot divergence (about 2 x 10(8) yr ago), though the
divergence of maize (C4 plant) from wheat (C3 plant) is supposed to have
occurred much later (6 x 10(7) yr ago).