The RING-H2 finger gene 1 ( RHF1 ) encodes an E3 ubiquitin ligase and participates in drought stress response in Nicotiana tabacum

Author： Xia Zongliang

Publisher： Springer Publishing Company

ISSN： 0016-6707

Source： Genetica, Vol.141, Iss.1-3, 2013-03, pp. : 11-21

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Abstract

Drought is one of the most important limiting factors for plant growth and development. To identify genes required for drought stress response in tobacco, one highly induced mRNA encoding a RING-H2 Finger gene (RHF1) was isolated by mRNA differential display. The full-length NtRHF1 encodes a protein of 273 amino acids and contains a single C3H2C3-type RING motif in its C-terminal region. NtRHF1 is an ortholog of Arabidopsis SDIR1 (salt- and drought-induced RING finger 1) (73 % identity to AtSDIR1). The recombinant NtRHF1 protein purified from E. coli exhibited an in vitro E3 ubiquitin ligase activity. Real-time quantitative PCR analysis indicated that the transcript levels of NtRHF1 were higher in aerial tissues and were markedly up-regulated by drought stress. Overexpression of NtRHF1 enhanced drought tolerance in transgenic tobacco plants while RNA silencing of NtRHF1 reduced drought tolerance. Further expression analysis by real-time PCR indicated that NtRHF1 participates in drought stress response possibly through transcriptional regulation of downstream stress-responsive genes NtLEA5, NtERD10C, NtAREB, and NtCDPK2 in tobacco. Together, these results demonstrated that NtRHF1 plays a positive role in drought stress tolerance possibly through transcriptional regulation of several stress-responsive marker genes in tobacco. This study will facilitate to improve our understanding of molecular and functional properties of plant RING-H2 finger proteins and to provide genetic evidence on the involvement of the RING-H2 E3 ligase in drought stress response in Nicotiana tabacum plants.