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
ABSTRACT
The objective of this study was to estimate genetic parameters and to investigate the type of gene action in controlling androgenesis in wheat. Two wheat cultivars of Grebe and Houtman were reciprocally crossed with two synthetic genotypes of Do1 and Pol and then a complete set of the parents, F1, reciprocal F1 [RF1], F2 and back-cross generations [BC1 and BC2] of each cross were used for anther culture. The ratio of responding anthers, the ratio of albino and green regenerants, and the number of embryoids per each responding anther were determined for different generations of each cross. The results showed a wide genetic variation for embryoid induction and plant regeneration among the parental lines and their progenies. The genetic model of additive-dominance effects could explain the variation among the generation means for the traits, indicating that their inheritance was relatively simple. The genetic analysis also showed predominance of additive genetic effects in genetic control of embryoid induction and green plant regeneration, implying possible improvement of these traits by selection in plant breeding programs. Maternal effects were also found for embryoid induction. The narrow-sense heritability for responding anthers, green plants, albino plants, green plants to total regenerants, and embryoids per responding anther in different crosses varied from 41% to 77%, 64% to 92%, 67% to 84%, 40% to 67% and 33% to 65%, respectively. In conclusion, it seems that the improvement of green plant regeneration in another culture technique can be achieved by appropriate breeding and selection programs
Subject(s)
Cytogenetic Analysis , Androgens/genetics , Androgens/biosynthesisABSTRACT
To identify quantitative trait loci [QTLs] controlling heading date and plant height, ninety nine F13 recombinant inbred lines [RILs] derived from barley cultivars Azumamugi x Kanto Nakate Gold cross were evaluated. The field trails were conducted at randomized complete block design with two and three replications in 2004 and 2005, respectively. Significant differences and transgrassive segregates were observed among lines for heading date and plant height. Composite interval mapping [CIM] was done based on linkage map constructed using 99 RILs and 100 markers including isozyme, morphological, STS and AFLP markers. A strong QTL controlling 26% phenotypic variation of heading date on chromosome 5HL was located near to the e07m25.3-e12m199.1 markers. The QTL had the same interval of the Sgh[2] locus. Allele inherited from Azumamugi parent in this locus decreased heading date. The QTL for heading date in the map interval of ABC261-ABG055 markers on chromosome 1HL could be identical with the eam8 locus and accounted for 11% of the phenotypic variation. New QTL for plant height was detected near to uzul locus on chromosome 3HL, explaining 52% of the phenotypic variation. The effect of allele transmitted from Azumamugi parent in this locus decreased plant height The QTLs identified on chromosomes 1HL, 3HL and 7HS in relation to earn8, uzul and dspl genes showed pleiotropic effects on controlling heading date and plant height