Abstract:

【Objective】 TaBβ-1, a gene encoding protein phosphatase 2A (PP2A) regulatory subunit (PR55) was cloned and its expression patterns in wheat under abiotic stresses were dissected for the purpose of providing a candidate gene for wheat breeding in response to various abiotic stresses. 【Method】 A wheat (Triticum aestivum L.) cultivar Hanxuan 10 was used as the plant material to clone the full-length cDNA sequence of TaBβ-1 by in silico cloning and RT-PCR. Suitable bioinformatics softwares were adopted to assay the structure of cDNA sequence, and the function of deduced TaBβ-1. The real-time quantitative PCR (qRT-PCR) method was employed to determine the expression patterns of TaBβ-1 in specific tissues and under abiotic stresses in wheat. 【Result】 A full-length cDNA sequence encoding regulatory subunit of PP2A was cloned from wheat and designated by the name of TaBβ-1, which is a 1 931 bp sequence with an 1 539 bp open reading frame. The putative amino acid sequence of TaBβ-1 contains 512 amino acids with a molecular mass of 57.1 kD and pI value of 5.87, which contains a CDC55 conserved domain, an alpha/beta domain, two PR55 conserved sites and six WD-repeats of PP2A subunit B. TaBβ-1 was detected in all tissues, including root, leaf and young-spike of wheat. The expression levels of TaBβ-1 at booting stage were root > spike > leaf. The highest expression level was identified from the seedling leaf among young-leaves at jointing, booting and flag-leaf expansion stages. TaBβ-1 was up-regulated by PEG, NaCl, cold and ABA treatments. Leaf cell membrane stabilities of transgenic Arabidopsis over-expressing TaBβ-1 were detected under well-watered and drought stress conditions. 【Conclusion】 TaBβ-1 is a member of PP2A regulatory subunit family. The expression level of TaBβ-1 in seedling leaf is much higher than that in the root and spike at booting stage, and in leaves at different stages. TaBβ-1 responds to multi-abiotic stresses but shows varied expression patterns, implying that TaBβ-1 involves in different signal pathways responding to abiotic stresses. Transgenic TaBβ-1 Arabidopsis lines show significantly higher cell membrane stabilities under drought stress condition than the wild type.

Key words: wheat, TaBβ-1, cloning, expression, abiotic stress