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DOI 10.1186/s40064-015-0997-4ance, it is important to elucidate the mechanism of GBNagoya 464-8601, Japan Full list of author information is available at the end of the articlemechanisms which allow them to adapt to unsuitable en-vironments. One of these mechanisms is the accumulation of compatible solutes. Compatible solutes differ among plant species and include sugar alcohols, amino acids and their derivatives, tertiary sulphonium compounds and quaternary ammonium compounds (Rhodes & Hanson 1993; Bohnert & Jensen 1996). Glycinebetaine (GB) is one of the most important compatible solutes. GB is present in bacteria, cyanobacteria, animals, and several plant families decrease the Tm of double-stranded DNA (Rees et al. 1993). The biological effects of GB on plant stress tolerance have been shown using near-isogenic lines in maize and transgenic plants (Saneoka et al. 1995; Yang et al. 1995; Nomura et al. 1995, 1998; Sakamoto et al. 1998; Mohanty et al. 2002). In near-isogenic lines of maize differing in levels of GB accumulation, lines with abundant GB showed higher salt tolerance than GB-deficient lines (Saneoka et al. 1995; Yang et al. 1995). However, most crop plants such as rice accumulate little GB and are sen-sitive to salt stress. Therefore, to improve plant salt toler-* Correspondence