Reference "Organ-specific and hormone-dependent expression of genes for serine carboxypeptidases during development and following germination of rice grains"

Reference ID

4866

Title

Organ-specific and hormone-dependent expression of genes for serine carboxypeptidases during development and following germination of rice grains

Source

Plant physiology, 1994, vol. 105, pp. 1275-1280

Authors (2)

Washio-K

Ishikawa-K

Abstract

Several cDNA clones encoding either serine carboxypeptidases or related proteins
of Oryza sativa L. were identified, and the abundance of the corresponding mRNA
in immature and germinated grains was examined. The deduced amino acid sequence
of each cDNA included key sequences, such as a pentapeptide (G-X-S-X-G/A) that
is conserved among many serine carboxypeptidases, and the putative protein
products were classified as two general and one novel type of cereal serine
carboxypeptidases. Two general types exhibited considerable homology to type I
and type III carboxypeptidases of cereal plants. The novel type encoded a serine
carboxypeptidase-like protein that was very similar to type III
carboxypeptidases of barley and wheat but had slight differences in both the N-
and the C-terminal sequences. The mRNAs of each of these carboxypeptidases were
observed in immature grains, and they decreased during maturation. The abundance
of mRNA for each class of carboxypeptidase increased again following germination
with the same time course and in a tissue-specific manner. The mRNAs for type I
and type III-like carboxypeptidases were abundant in germinated embryos composed
of leaf, root, and scutellum, whereas the mRNA for type III carboxypeptidase was
conspicuous in endosperm that contained the aleurone layer. Altered amounts of
mRNA in deembryonated half-grains in response to phytohormones, such as
gibberellic acid and abscisic acid, were only detectable in the case of type III
carboxypeptidase. Southern blot analysis using rice genomic DNA revealed the
simple organization of each gene for these three classes of carboxypeptidases.