Reference "Molecular characterization and differential expression of cytokinin-responsive type-A response regulators in rice (Oryza sativa)"

Reference ID

11087

Title

Molecular characterization and differential expression of cytokinin-responsive type-A response regulators in rice (Oryza sativa)

Source

BMC Plant Biol, 2006, vol. 6, pp. 1-1

Authors (3)

Jain-M	Tyagi-A-K
Khurana-J-P

Abstract

ABSTRACT: BACKGROUND: The response regulators represent the elements of
bacterial two-component system and have been characterized from dicot plants
like Arabidopsis but little information is available on the monocots, including
the cereal crops. The aim of this study was to characterize type-A response
regulator genes from rice, and to investigate their expression in various organs
as well as in response to different hormones, including cytokinin, and
environmental stimuli. RESULTS: We have identified ten genes encoding type-A
response regulators by analysis of the whole genome sequence of rice based upon
their high sequence identity within the receiver domain. The exon-intron
organization, intron-phasing as well as chromosomal location of all the RT-PCR
amplified rice (Oryza sativa) response regulator (OsRR) genes has been analyzed.
The transcripts of OsRR genes could be detected by real-time PCR in all organs
of the light- and dark-grown rice seedlings/plants, although there were
quantitative differences. The steady-state transcript levels of most of the OsRR
genes increased rapidly (within 15 min) on exogenous cytokinin application even
in the presence of cycloheximide. Moreover, the expression of the OsRR6 gene was
enhanced in rice seedlings exposed to salinity, dehydration and low temperature
stress. CONCLUSION: The ten type-A response regulator genes identified in rice,
the model monocot plant, show overlapping/differential expression patterns in
various organs and in response to light. The induction of OsRR genes by
cytokinin even in the absence of de novo protein synthesis qualifies them to be
primary cytokinin response genes. The induction of OsRR6 in response to
different environmental stimuli indicates its role in cross-talk between abiotic
stress and cytokinin signaling. These results provide a foundation for further
investigations on specific as well as overlapping cellular functions of type-A
response regulators in rice.