Inducer of CBF (C-repeat binding factors) expression 1, 2 (ICE1/2) is an important transcription factor that plays a significant role in the cold stress response pathway. Zoysiagrasses are warm-season turfgrasses and are prone to browning at the starting of winter. By understanding the cold response mechanism, the cold tolerance of some zoysiagrasses such as Zoysia matrella or Z. pacifica showing less cold hardiness can be improved to withstand low temperatures. Arabidopsis and Z. japonica ICE1, 2 have already been characterized and reported. Using in-silico analysis, we predicted the putative ICE1, 2 genes in Z. matrella and Z. pacifica. The comparative sequence analyses revealed conservation of the bHLH (basic helix-loop-helix) domain in the putative ICE1 and ICE2 genes in Z. matrella and Z. pacifica. Also, two copies of ICE2 were seen in Z. matrella. There were huge variations in the immediate regulatory region of the ICE1 and ICE2 genes which may be a reason for different cold tolerance levels in the three Zoysiagrasses. The predicted sequences of the ICE1,2 genes in Z. matrella and Z. pacifica can be utilized to further investigate interactions with CBF3 and their implications in cold stress tolerance, which will provide new insight into molecular mechanisms in regulating cold tolerance.
Figures & Tables
Fig. 1. Conserved domain analysis of the Zoysia A) Inducer of CBF expression 1 (ICE1 ) putative protein sequences and B) Inducer of CBF expression 2 (ICE2 ) putative protein sequences. Two major domains related to the ICE1 protein; bHLH_AtAMS_like (in blue) and ACT_UUR-ACR-like (in yellow) were identified in all three zoysiagrasses. An additional domain, belonging to the PLN02983 superfamily was identified in Z. matrella ICE1 (Zmw-ICE1 ) and Z. pacifica ICE1 (Zpz-ICE1 ) (highlighted in grey). The single amino acid polymorphic sites are in red, and the in/del regions have been highlighted in green. cov: Coverage; pid: Percent identity; Zjn: Z. japonica .