Abscisic acid response element binding factor 1 is required for establishment of Arabidopsis seedlings during winter Pitamber Dutt Sharma • Neha Singh • Paramvir Singh Ahuja • Thamalampudi Venkata Reddy Received: 9 October 2010 / Accepted: 7 December 2010 Ó Springer Science+Business Media B.V. 2010 Abstract Abscisic acid (ABA) plays a crucial role in abiotic stress response apart from its influence on growth and development of a plant. Our studies on abscisic acid response element binding factor 1 (ABF1) gene in Ara- bidopsis demonstrate that it is required for seedling establishment during winter. ABF1 is also involved in regulating seed dormancy and seed germination to some extent. Analysis of transcriptional activity of ABF1 pro- moter reveals that ABF1 expresses specifically in trichomes of young leaves and constitutively in cotyledons, roots, older leaves and flowers. The expression is induced upon exposure to ABA, cold and heat. The alignment of cDNAs of ABF1 (At1g49720) and At1g49730 (encodes a protein kinase of unknown function), reveals an overlap of 88 bp at their 3 0 UTR region suggesting that they can potentially form natural cis-antisense mRNAs pair in a tail-to-tail manner. Analysis by Genevestigator microarray stress response viewer further supports the regulatory role of these genes. An inverse proportion is observed in the transcription the two loci in number of stress responses. The abf1 mutants do not show any seedling establishment defects when grown under standard growth conditions. The mutant seedlings exhibit growth defects during winter in the western Himalayan region. Our study also signifies the importance of functional analysis for mutant phenotypes in natural habitats by reverse genetic approaches, in order to identify specific function of particular gene/s whose expression level is altered upon exposure to changes in environmental cues such as temperature and light. Keywords Abscisic acid Á Environmental adaptation Á Natural cis-antisense mRNA pair Á Seedling establishment Abbreviations ABA Abscisic acid ABRE Abscisic acid response element ABF1 ABRE binding factor1 CBF C-Repeat binding factor CDS Coding DNA sequence MS Murashige and Skoog medium Wt Wild type Introduction During growth and development, plants experience various fluctuations in environmental parameters besides biotic stresses. Plants are evolved with different cellular and molecular mechanisms for stress tolerance through various genetic orchestrations and physiological regulations. Abscisic acid (ABA) is a major plant hormone that regulates plant development and stress through modulation of expression of a cascade of genes at the genetic level and the control of stomatal closure at physiological level [1]. Developmental events regulated by ABA include early embryogenesis, seed germination, seed dormancy, seedling growth and senescence. ABA also acts in different abiotic stress tolerance mechanisms like dehydration, salinity, cold and oxidative stress [1, 2]. Exposure of seed and seedlings to ABA has an inhibitory effect on germination and seedling growth, respectively. Several forward genetic screens based P. D. Sharma Á N. Singh Á P. S. Ahuja Á T. V. Reddy (&) Biotechnology Division, Institute of Himalayan Bioresource Technology-CSIR, Palampur 176061, Himachal Pradesh, India e-mail: tvr_gene_2000@yahoo.com; venkata.thamalampudi@itc.in Present Address: T. V. Reddy Biosciences Division, ITC R&D Centre, No: 3, 1st Main 1st Phase, Peenya Industrial Area, Bangalore 560058, India 123 Mol Biol Rep DOI 10.1007/s11033-010-0664-3