Reference "Cloning and functional analysis of two gibberellin 3 beta -hydroxylase genes that are differently expressed during the growth of rice"

Reference ID

6531

Title

Cloning and functional analysis of two gibberellin 3 beta -hydroxylase genes that are differently expressed during the growth of rice

Source

Proceedings of the National Academy of Sciences of the United States of America, 2001, vol. 98, pp. 8909-8914

Authors (6)

Itoh-H	Ueguchi-Tanaka-M
Sentoku-N	Kitano-H
Matsuoka-M	Kobayashi-M

Abstract

We have cloned two gibberellin (GA) 3 beta-hydroxylase genes, OsGA3ox1 and
OsGA3ox2, from rice by screening a genomic library with a DNA fragment obtained
by PCR using degenerate primers. We have used full-scan GC-MS and Kovats
retention indices to show function for the two encoded recombinant fusion
proteins. Both proteins show 3 beta-hydroxylase activity for the steps GA(20) to
GA(1), GA(5) to GA(3), GA(44) to GA(38), and GA(9) to GA(4). In addition,
indirect evidence suggests that the OsGA3ox1 protein also has 2,3-desaturase
activity, which catalyzes the steps GA(9) to 2,3-dehydro-GA(9) and GA(20) to
GA(5) (2,3-dehydro GA(20)), and 2 beta-hydroxylase activity, which catalyzes the
steps GA(1) to GA(8) and GA(4) to GA(34). Molecular and linkage analysis maps
the OsGA3ox1 gene to the distal end of the short arm of chromosome 5; the
OsGA3ox2 gene maps to the distal end of the short arm of chromosome 1 that
corresponds to the D18 locus. The association of the OsGA3ox2 gene with the d18
locus is confirmed by sequence and complementation analysis of three d18
alleles. Complementation of the d18-AD allele with the OxGA3ox2 gene results in
transgenic plants with a normal phenotype. Although both genes show transient
expression, the highest level for OsGA3ox1 is from unopened flower. The highest
level for OsGA3ox2 is from elongating leaves.