Os09g0456200

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Annotated Information

Function

OsbZIP72 was an important regulator in abiotic stress response and ABA signaling transduction pathway[1]. The phytohormone abscisic acid (ABA) plays an essential role in plant adaption to drought stress.When stress was sensed by plants, the ABA level was elevated, which consequently activated the ABA response genes. A major group of transactivation factors binding to ABREs (ABA responsive elements) were basic leucine zipper proteins (bZIPs) that contained basic regions for DNA binding and leucine zipper regions for dimerization[2] [3] [4]. Yeast one hybrid experiment in this study showed that OsbZIP72 could specifically bind to ABRE element . This result indicated that OsbZIP72 could bind to the ABRE in promoters of the down stream genes and was involved in the ABA signaling pathway.In vivo analysis of TRAB1 showed that it could transactivate the downstream reporter genes in response to ABA application[5].

Expression

The expression levels of OsbZIP72were relatively high in all tissues, and the expression levels were induced by PEG, NaCl, Cold, ABA and ACC[1]. As compared among different tissues of the same genes, the expression levels of OsbZIP72 were relatively low in both root and stem[1]. The expression pattern in response to environmental stresses and several hormones was also investigated. The expression levels of OsbZIP72were elevated by MeJA and NAA treatment, while, repressed by pathogen treatment[1]. The enhancement of drought tolerance by overexpression of several group A AtbZIPs has been reported [6] [7].OsbZIP72is the first positive regulator identified in this group for rice drought tolerance. Transgenic rice plants overexpressing OsbZIP72 were hypersensitive to ABA and had elevated expression of the ABA responsive genes[1].

Evolution

In order to better understand the relationships within the group A bZIPs of rice and Arabidopsis, the entire protein sequences of this group from rice and Arabidopsis were aligned and a bootstrap NJ-tree was constructed using ClustalX [8](Fig.1). According to this phylogenetic tree, all of the bZIPs could be classified into three subgroups. Each subgroup contains both rice and Arabidopsis bZIPs, indicating that the divergence of these subgroups predated the divergence of dicots and monocots. It also indicated that the protein sequences of these bZIPs were well conserved between dicots and monocots[1].

Labs working on this gene

National Center for Gene Research and Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 500 Caobao Road, 200233 Shanghai, China

The Department of Biotechnology, Government of India, the University Grants Commission, and the Council of Scientific and Industrial Research, New Delhi (research fellowship to A.N.)

References

[1]. Guojun Lu;Chenxi Gao;Xingnan Zheng;Bin Han(2009) Identification of OsbZIP72 as a positive regulator of ABA response and drought tolerance in rice. Planta, 229(3): 605-615 [2]. Kim SY, Chung HJ, Thomas TL (1997) Isolation of a novel class of bZIP transcription factors that interact with ABA-responsive and embryo-speciWcation elements in the Dc3promoter using a modiWed yeast one-hybrid system. Plant J 11:1237–1251

[3]. Uno Y, Furihata T, Abe H, Yoshida R, Shinozaki K, YamaguchiShinozaki K (2000) Arabidopsisbasic leucine zipper transcription factors involved in an abscisic acid-dependent signal transduction pathway under drought and high-salinity conditions. Proc Natl Acad Sci USA 97:11632–11637

[4]. Choi H, Hong J, Ha J, Kang J, Kim SY (2000) ABFs, a family of ABA responsive element binding factors. J Biol Chem 275:1723–1730

[5]. Hobo T, Kowyama Y, Hattori T (1999) A bZIP factor, TRAB1, interacts with VP1 and mediates abscisic acid-induced transcription. Proc Natl Acad Sci USA 96:15348–15353

[6]. Kang JY, Choi HI, Im MY, Kim SY (2002) Arabidopsisbasic leucine zipper proteins that mediate stress-responsive abscisic acid signaling. Plant Cell 14:343–357

[7]. Oh SJ, Song SI, Kim YS, Jang HJ, Kim SY, Kim M, Kim YK, Nahm BH, Kim JK (2005) ArabidopsisCBF3/DREB1A and ABF3 in transgenic rice increased tolerance to abiotic stress without stunting growth. Plant Physiol 138:341–351

[8]. Thompson JD, Gibson TJ, Plewniak F, Jeanmougin F, Higgins DG (1997) The CLUSTAL_X windows interface: Xexible strategies for multiple sequence alignment aided by quality analysis tools.Nucleic Acids Res 25:4876–4882