Molecular cloning and functional analysis of a novel phytoglobin gene from the alpine plant Stipa purpurea

Background: Stipa purpurea, the dominant species of the alpine steppe in the Tibetan Plateau, survives well under various abiotic stresses including drought, hypoxia and chilling.Aims: To understand the molecular mechanism by which alpine plants including S. purpurea adapt to the abiotic environmental factors of the Tibetan Plateau.Methods: We cloned the coding domain sequence of one Phytogb gene from S. purpurea using the rapid amplification of cDNA ends method and analysed its function by heterologous expression in Arabidopsis.Results: The Phytogb gene, which we named StipurPhytogb1, included 474 nucleotides and encoded a protein of 157 amino acids. Functional analyses showed that StipurPhytogb1 could improve the resistance of transgenic Arabidopsis to drought and hypoxia caused by waterlogging. Further analyses suggested that StipurPhytogb1 improved the above resistance by inhibiting nitric oxide accumulation and mediating the induction of antioxidant enzyme activities to scavenge reactive oxygen species.Conclusion: These findings indicate that StipurPhytogb1 may play an essential role in the adaptation of S. purpurea to drought and the hypoxic environment of the Tibetan Plateau and has potential as a candidate gene for genetic transformation to improve plant stress tolerance.