Ghazale Khaksar1, Badraldin Ebrahim Sayed Tabatabaei2,3, Ahmad Arzani1, Cyrus Ghobadi4, Esmaeil Ebrahimie5,6. 1. Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. 2. Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. 3. Department of Molecular Plant Physiology, Utrecht University, Padualaan 8, 3584CH, Utrecht , The Netherlands. 4. Department of Horticulture, College of Agriculture, Isfahan University of Technology, Isfahan, Iran. 5. Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, 73761, Iran. 6. Discipline of Genetics, School of Biological Science, University of Adelaide, Adelaide, 5001, SA, Australia.
Abstract
BACKGROUND: Pomegranate fruit (Punica granatum L.) is a rich source of anthocyanin pigments resulting in vibrant colours and anti-oxidant contents. Although the intensity and pattern of anthocyanin biosynthesis in fruit are strongly influenced by R2R3-MYB transcription factors, little is known about the regulation and role of MYB in anthocyanin pathway of pomegranate. OBJECTIVES: The present study was conducted to elucidate the relationship between the expression of MYB transcription factor and the anthocyanin accumulation during the colour development phase of pomegranate fruits. MATERIALS AND METHODS: In this work, R2R3-MYB transcription factor (PgMYB) was isolated and characterized from pomegranate skin through RACE-PCR. The expression of PgMYB gene was monitored in three distinct pomegranate accessions with distinctive skin colour and pattern by semi-quantitative RT-PCR. RESULTS: The results indicated a strong association between skin colour in mature pomegranate fruits with the PgMYB transcripts. The highest expression level of PgMYB gene was observed in Poost Siyah Yazd (dark purple skin) throughout the ripening process. Furthermore, comparison of PgMYB amino acid sequences with those of R2R3-MYB family in grapevine, eucalyptus, peach, cacao, populus and Arabidopsis demonstrated that this protein shares high similarity (75-85% amino acid identity) with their conserved MYB domain. Computational structure prediction of PgMYB showed that the three conserved amino acids (Asn, Lys and Lys) are present in the same position of the MYB domain. CONCLUSIONS: It is speculated that PgMYB gene influences the fruit colour and could be used to improve the accumula-tion of anthocyanin pigments in the pomegranate fruit.
BACKGROUND:Pomegranate fruit (Punica granatum L.) is a rich source of anthocyanin pigments resulting in vibrant colours and anti-oxidant contents. Although the intensity and pattern of anthocyanin biosynthesis in fruit are strongly influenced by R2R3-MYB transcription factors, little is known about the regulation and role of MYB in anthocyanin pathway of pomegranate. OBJECTIVES: The present study was conducted to elucidate the relationship between the expression of MYB transcription factor and the anthocyanin accumulation during the colour development phase of pomegranate fruits. MATERIALS AND METHODS: In this work, R2R3-MYB transcription factor (PgMYB) was isolated and characterized from pomegranate skin through RACE-PCR. The expression of PgMYB gene was monitored in three distinct pomegranate accessions with distinctive skin colour and pattern by semi-quantitative RT-PCR. RESULTS: The results indicated a strong association between skin colour in mature pomegranate fruits with the PgMYB transcripts. The highest expression level of PgMYB gene was observed in Poost Siyah Yazd (dark purple skin) throughout the ripening process. Furthermore, comparison of PgMYB amino acid sequences with those of R2R3-MYB family in grapevine, eucalyptus, peach, cacao, populus and Arabidopsis demonstrated that this protein shares high similarity (75-85% amino acid identity) with their conserved MYB domain. Computational structure prediction of PgMYB showed that the three conserved amino acids (Asn, Lys and Lys) are present in the same position of the MYB domain. CONCLUSIONS: It is speculated that PgMYB gene influences the fruit colour and could be used to improve the accumula-tion of anthocyanin pigments in the pomegranate fruit.
Authors: Amanda R Walker; Elizabeth Lee; Jochen Bogs; Debra A J McDavid; Mark R Thomas; Simon P Robinson Journal: Plant J Date: 2007-03 Impact factor: 6.417