Reference "Isolation and characterization of a rice gene encoding a basic chitinase"

Reference ID

5366

Title

Isolation and characterization of a rice gene encoding a basic chitinase

Source

Molecular & General Genetics, 1991, vol. 226, pp. 289-296

Authors (2)

Zhu-Q

Lamb-C-J

Abstract

Chitinase, which catalyzes the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine
linkages of the fungal cell wall polymer chitin, is involved in inducible
defenses of plants. A basic chitinase genomic sequence was isolated from a rice
(Oryza sativa L.) genomic library using a bean chitinase gene fragment as a
probe. The complete nucleotide sequence of the rice chitinase RCH10 gene was
determined, and shown to contain an open reading frame with no introns, encoding
a polypeptide of 336 amino acids. This polypeptide consists of a 21 amino acid
signal peptide, a hevein domain, and a chitinase catalytic domain. The RCH10
gene has 63% identity at the nucleotide level and 75% identity at the amino acid
level with chitinase genes from dicotyledonous plants such as bean, potato, and
tobacco. A gene fusion of trpE and the coding region of RCH10 expressed in
Escherichia coli gave a product that reacted with antiserum to bean chitinase,
confirming the identity of RCH10 as a rice chitinase gene. Primer extension
analysis identified two transcription start sites 53 bp and 55 bp upstream from
the translation initiation codon. The 5' flanking region contains TATA and CAAT
boxes, and the 3' region contains an AATAA polyadenylation signal. Southern blot
hybridization indicated that there is a family of chitinase genes in the rice
genome. Northern blot analysis showed that the RCH10 chitinase gene is induced
in suspension cultured cells by a fungal cell wall elicitor. Rice chitinase
transcripts accumulate to a high level in roots, but only low levels are found
in stem and leaf tissue.