Abstract:

【Objective】 Protein phosphorylation plays an important role in mediating the abiotic stress signal transduction in plants. In this study, the responding characterizations of TaMPK1a-1, a novel mitogen-activated protein kinase gene identified under deficient-Pi condition in wheat, were elucidated. 【Methods】 TaMPK1a-1 with a up-regulated expression pattern under deficienct-Pi was identified based on cDNA-AFLP approach. The gene structure and the protein features were analyzed by bioinformatics tools. The responding characterizations of TaMPK1a-1 to deficient-Pi were explored based on semi-quantitative RT-PCR method. 【Results】 The cDNA length of TaMPK1a-1 was 2 170 bp, containing an open reading frame of 1 737 bp and encoding a polypeptide of 578-aa. There were two dual phosphorylation sites in TaMPK1a-1, including one TEY motif and one TDY motif. Under normal Pi supply condition (2 mmol?L-1 Pi), no transcripts of TaMPK1a-1 in roots and leaves of two wheat cultivars, including high-P efficiency cultivar Shixin8282 and low-P efficiency cultivar Ji7369, were detected. Under deficient-Pi (20 μmol?L-1 Pi) condition, the expression of TaMPK1a-1 in the roots and the leaves of above two cultivars were all induced. Compared with Ji7369, the transcripts of TaMPK1a-1 in roots and leaves in Shixin828 under deficient-Pi condition were much strongly enhancement. 【Conclusion】 The cascade pathway of TaMPK1a-1 in wheat not only affects the responding ability to low-Pi stress signal, but also possibly plays an important role in regulation of plant P use efficiency under deficient-Pi condition.

Key words: wheat (Triticum aestivum L.)')">wheat (Triticum aestivum L.), mitogen-activated protein kinase gene, low-pi stress, cloning, expression