Alternative splicing in the coding region of Ppo-A1 directly influences the polyphenol oxidase activity in common wheat (Triticum aestivum L.)
Sun, Y., He, Z., Ma, W. and Xia, X. (2011) Alternative splicing in the coding region of Ppo-A1 directly influences the polyphenol oxidase activity in common wheat (Triticum aestivum L.). Functional & Integrative Genomics, 11 (1). pp. 85-93.
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Polyphenol oxidase (PPO) plays a crucial role in browning reactions in fresh and processed fruits and vegetables, as well as products made from cereal grains. Common wheat (Triticum aestivum L.) has a large genome, representing an interesting system to advance our understanding of plant PPO gene expression, regulation and function. In the present study, we characterized the expression of Ppo-A1, a major PPO gene located on wheat chromosome 2A, using DNA sequencing, semi-quantitative RT-PCR, PPO activity assays and whole-grain staining methods during grain development. The results indicated that the expression of the Ppo-A1b allele was regulated by alternative splicing of pre-mRNAs, resulting from a 191-bp insertion in intron 1 and one C/G SNP in exon 2. Eight mRNA isoforms were identified in developing grains based on alignments between cDNA and genomic DNA sequences. Only the constitutively spliced isoform b encodes a putative full-length PPO protein based on its coding sequence whereas the other seven spliced isoforms, a, c, d, e, f, g and h, have premature termination codons resulting in potential nonsense-mediated mRNA decay. The differences in expression of Ppo-A1a and Ppo-A1b were confirmed by PPO activity assays and whole grain staining, providing direct evidence for the influence of alternative splicing in the coding region of Ppo-A1 on polyphenol oxidase activity in common wheat grains
|Publication Type:||Journal Article|
|Murdoch Affiliation:||Centre for Comparative Genomics|
|Copyright:||© 2010 Springer-Verlag.|
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