ORIGINAL ARTICLE Expression and functional analysis of NUCLEAR FACTOR-Y, subunit B genes in barley Mingxiang Liang • David Hole • Jixiang Wu • Tom Blake • Yajun Wu Received: 20 August 2011 / Accepted: 12 October 2011 Ó Springer-Verlag 2011 Abstract NUCLEAR FACTOR-Y, subunit B (NF-YB) comprises a multigene family in plants and has been shown to play important roles in growth, development, and response to environmental stress. In this study, five NF-YBs containing the full-length coding region were obtained from barley (Hordeum vulgare) through database sequence analysis, cloning, and sequencing. Sequence alignment and phylogenetic analysis showed that HvNF-YB3 and HvNF- YB1 were clustered with NF-YB2 and NF-YB3 in Arabidopsis, suggesting these NF-YBs are evolutionary and functionally related. To test this hypothesis, HvNF- YB3 and HvNF-YB1 were overexpressed in Arabidopsis. Overexpression of HvNF-YB1 greatly promoted early flowering in Arabidopsis, supporting that HvNF-YB1may have conserved gene function in flowering time control as NF-YB2 and NF-YB3 in Arabidopsis. Overexpression of HvNF-YB3 in Arabidopsis had no effect on flowering time. An analysis of barley single-nucleotide polymorphism (SNP) data, however, revealed a significant association between an HvNF-YB3 SNP and heading date. While it is unknown whether HvNF-YB3 directly contributes to heading date regulation, the results implied that HvNF- YB3 may also have conserved function in flowering time (heading date in barley) control. Further studies are needed to directly verify these gene functions in barley. Barley NF-YBs showed different expression patterns associated with tissue types, developmental stages, and response to different stress treatments, suggesting that barley NF-YBs may be involved in other physiological processes. Keywords Barley  NF-YB  Heading date  Flowering time  SNP  Arabidopsis Abbreviations HAP Heme activator protein NF-Y NUCLEAR FACTOR-Y CBF-A CCAAT-Binding Factor A CO CONSTANS GI GIGANTAE SOC1 SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 FT FLOWERING LOCUS T ABA Abscisic acid SNP Single-nucleotide polymorphism Electronic supplementary material The online version of this article (doi:10.1007/s00425-011-1539-0) contains supplementary material, which is available to authorized users. M. Liang  D. Hole  Y. Wu Department of Plants, Soils, and Climate, Utah State University, Logan, UT 84322, USA e-mail: liangmx@njau.edu.cn D. Hole e-mail: david.hole@usu.edu M. Liang College of Resources and Environmental Sciences, Nanjing Agriculture University, 210095 Nanjing, People& s Republic of China J. Wu Department of Plant Science, South Dakota State University, Brookings, SD 57007, USA e-mail: Jixiang.wu@sdstate.edu T. Blake Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA e-mail: blake@montana.edu Y. Wu (&) Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA e-mail: yajun.wu@sdstate.edu 123 Planta DOI 10.1007/s00425-011-1539-0