Conservation and differentiation of polyphenol oxidase (PPO) gene introns in Triticum and Aegilops tauschii Coss.
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Two genes (PPO1 and PPO2), located in the homoeologous chromosome group 2 of common wheat, play an important role in controlling the kernel polyphenol oxidase acitivity, which influence indirectly the time-dependent darkening and discoloration in Asian noodles and other wheat-based products. In the present study, intron sequences of PPO genes (PPO1 and PPO2) in Triticum urartu Tumanian ex Gandilyan, T. monococcum L. and Aegilops tauschii Coss., together with NCBI retrieved wheat PPO sequnces in different ploidy levels, were systematically investigated. The results highlighted that PPO intron sequences are conserved at lower classification levels (species/subspecies level), and the allopolyploidization process of common wheat has little effect on them. Sequence differences in PPO gene introns may occur long before the differentiation of the A and D genome of T. urartu and Ae. tauschii, respectively. It’s interesting that different PPO intron regions vary into two different intron splicing rule within one same gene sequence: intron 1 is all fitted to the “GT-AG” splicing rule while intron 2 is the “GC-AG”. In addition, the phylogenetic analysis showed the obvious differences existed in materials from different geographical distribution in T. monococcum ssp. aegilopoies, which suggest that some of them had close genetic relationship with T. urartu. These findings contribute to the application of PPO gene introns in favorable allele screening, functional molecular marker development, and phylogenetic analysis.
KeywordsPolyphenol oxidase Intron Allopolyploidization Triticum urartu Triticum monococcum Aegilops taushcii
We thank Professor Bihua Wu, Dr. Lianquan Zhang of Sichuan Agricultural University for providing their valuable synthetic hexaploid wheat and other materials collected.
This project was partially funded by Special Fund for Strategic Pilot Technology of Chinese Academy of Sciences (Class A, No. XDA08030106).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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