• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.94-104
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• 2011

Salt stress is a major environmental factor influencing plant growth and development. To identify salt tolerance determinants, we systematically screened salt sensitive rice mutants by use of the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on the salt sensitive mutant line, designated SSM-1. A gene encoding a NAC transcription factor homologue was disrupted by the insertion of a Ds transposon into SSM-1 line. The OsNAC075 gene (EU541472) has 7 exons and encodes a protein (486-aa) containing the NAC domain in its N-terminal region. Sequence comparison showed that the OsNAC075 protein had a strikingly conserved region at the N-terminus, which is considered as the characteristic of the NAC protein family. OsNAC075 protein was orthologous to Arabidopsis thaliana ANAC075. Phylogenetic analysis confirmed OsNAC075 belonged to the OsNAC3 subfamily, which plays an important role in response to stress stimuli. RT-PCR analysis showed that the expression of OsNAC075 gene was rapidly and strongly induced by stresses such as NaCl, ABA and low temperature ($4^{\circ}C$). Our data suggest that OsNAC075 holds promising utility in improving salt tolerance in rice.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.325-334
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• 2010

Transcriptional regulation in response to salt in mutant lines was investigated using oligonucleotide microarrays. In order to characterize the salt-responsive genes in rice, the expression profiles of transcripts that responded to salt-treatment were monitored using the microarrays. In the microarray analysis, among 37,299 reliable genes, 5,101, 2,758 and 2,277 genes were up-regulated by more than 2-fold using the salt treatment, while the numbers of down-regulated genes were 4,619, 3,234, and 1,878 in the WT, ST-495, and ST-532, respectively. From genotype changes induced by gamma ray mutagenesis, 3,345 and 2,397 genes were up-regulated, while 2,745 and 2,075 genes were down-regulated more than 2-fold in the two untreated mutants lines compared with untreated WT, respectively. A total of 3,108 and 2,731 genes were up-regulated more than 2-fold, while 3,987 and 3,660 genes were down-regulated by more than 2-fold in the salt treatment of the two mutants lines compared with the salt treated WT, respectively. The expressions of membrane transporter genes such as OsAKT1, OsKUP, and OsNAC increased more severely in ST-495 and ST-532 than in the WT. The expressions of the proline accumulation related genes such as OsP5CS and OsP5CR were also markedly increased in the salt tolerant mutants when compared to the WT plant.