Deletion of the miR172 target site in a TOE-type gene is a strong candidate variant for dominant double-flower trait in Rosaceae (original) (raw)
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A miR172 target-deficient AP2-like gene correlates with the double flower phenotype in roses
Scientific Reports
One of the well-known floral abnormalities in flowering plants is the double-flower phenotype, which corresponds to flowers that develop extra petals, sometimes even containing entire flowers within flowers. Because of their highly priced ornamental value, spontaneous double-flower variants have been found and selected for in a wide range of ornamental species. Previously, double flower formation in roses was associated with a restriction of AGAMOUS expression domain toward the centre of the meristem, leading to extra petals. Here, we characterized the genomic region containing the mutation associated with the switch from simple to double flowers in the rose. An APETALA2-like gene (RcAP2L), a member of the Target Of EAT-type (TOE-type) subfamily, lies within this interval. In the double flower rose, two alleles of RcAP2L are present, one of which harbours a transposable element inserted into intron 8. This insertion leads to the creation of a miR172 resistant RcAP2L variant. Analyses of the presence of this variant in a set of simple and double flower roses demonstrate a correlation between the presence of this allele and the double flower phenotype. These data suggest a role of this miR172 resistant RcAP2L variant in regulating RcAGAMOUS expression and double flower formation in Rosa sp.
Nature Genetics, 2007
It is commonly thought that deep phylogenetic conservation of plant microRNAs (miRNAs) and their targets 1,2 indicates conserved regulatory functions. We show that the blind (bl) mutant of Petunia hybrida 3 and the fistulata (fis) mutant of Antirrhinum majus 4,5 , which have similar homeotic phenotypes, are recessive alleles of two homologous miRNA-encoding genes. The BL and FIS genes control the spatial restriction of homeotic class C genes 6,7 to the inner floral whorls, but their ubiquitous early floral expression patterns are in contradiction with a potential role in patterning C gene expression. We provide genetic evidence for the unexpected function of the MIRFIS and MIRBL genes in the center of the flower and propose a dynamic mechanism underlying their regulatory role. Notably, Arabidopsis thaliana, a more distantly related species, also contains this miRNA module but does not seem to use it to confine early C gene expression to the center of the flower. The spatial partitioning of floral homeotic gene expression is crucial for wild-type flower development. Several transcription factors participate in this control, which aims at transcriptional silencing of the so-called 'C genes' outside their genuine expression domain in the inner two whorls of the flower, where they govern reproductive organ (stamen and carpel) development 6,7. The functions of orthologous repressor genes, constituting the A function of the floral ABCs 6 , are, in part, comparable between different species 8 , as are some of the cis-acting regulatory regions within the large second intron of their structurally and functionally related target C genes AGAMOUS (AG) in Arabidopsis thaliana 7 , pMADS3 in P. hybrida 9 and PLENA and FARINELLI (PLE and FAR) in A. majus 10. There are also exceptions to these overall similarities among species. For instance, orthologs of the A. thaliana APETALA2 (AP2) gene have no role in C gene regulation in P. hybrida 11 or A. majus 12 , raising the question of whether other genes fulfill this role. Candidates are the BL gene in P. hybrida and FIS in A. majus, which, when mutated, show markedly similar homeotically converted stamenoid petals in their second floral whorls 4,5 (Fig. 1).
Development, 2010
The ABC model of flower development explains how three classes of homeotic genes confer identity to the four types of floral organs. In Arabidopsis thaliana, APETALA2 (AP2) and AGAMOUS (AG) represent A- and C-class genes that act in an antagonistic fashion to specify perianth and reproductive organs, respectively. An apparent paradox was the finding that AP2 mRNA is supposedly uniformly distributed throughout young floral primordia. Although miR172 has a role in preventing AP2 protein accumulation, miR172 was reported to disappear from the periphery only several days after AG activation in the center of the flower. Here, we resolve the enigmatic behavior of AP2 and its negative regulator miR172 through careful expression analyses. We find that AP2 mRNA accumulates predominantly in the outer floral whorls, as expected for an A-class homeotic gene. Its pattern overlaps only transiently with that of miR172, which we find to be restricted to the center of young floral primordia from ear...
Plant physiology, 2015
Leafy flowers are the major symptoms of Peanut witches' broom (PnWB) phytoplasma infection in Catharanthus roseus. The orthologs of the PHYL1 effector of PnWB from other species of phytoplasma can trigger the proteasomal degradation of several MADS-box transcription factors (MTFs), resulting in leafy flower formation. In contrast, the flowering negative regulator genes-SHORT VEGETATIVE PHASE (SVP) was up-regulated in PnWB-infected C. roseus plants, but most miRNA genes were repressed expressions. Coincidentally, transgenic Arabidopsis plants expressing the PHYL1 of PnWB gene (PHYL1 plants), which show leafy flower phenotypes, up-regulate SVP of Arabidopsis (AtSVP) but repress a putative regulatory microRNA (miRNA) of AtSVP - miR396. However, the mechanism by which PHYL1 regulates AtSVP and miR396 is unknown, and the evidence of miR396-mediated AtSVP degradation is lacking. Here, we show that miR396 triggers AtSVP mRNA decay using genetic approaches, a reporter assay, and high-th...
The New phytologist, 2018
Age-regulated microRNA156 (miR156) and targets similarly control the competence to flower in diverse species. By contrast, the diterpene hormone gibberellin (GA) and the microRNA319-regulated TEOSINTE BRANCHED/CYCLOIDEA/PCF (TCP) transcription factors promote flowering in the facultative long-day Arabidopsis thaliana, but suppress it in the day-neutral tomato. We combined genetic and molecular studies and described a new interplay between gibberellin and two unrelated miRNA-associated pathways that modulates tomato transition to flowering. Tomato PROCERA/DELLA activity is required to promote flowering along with the miR156-targeted SQUAMOSA PROMOTER BINDING-LIKE (SPL/SBP) transcription factors by activating SINGLE FLOWER TRUSS (SFT) in the leaves and the MADS-Box gene APETALA1(AP1)/MC at the shoot apex. Conversely, miR319-targeted LANCEOLATE represses floral transition by increasing GA levels and inactivating SFT in the leaves and AP1/MC at the shoot apex. Importantly, the combinati...
Gene, 2018
Evolutionarily conserved microRNAs such as miR156, miR159, miR167 and miR172 tightly regulate the extensive array of gene expression during flowering in plants, through instant and long-term alterations in the expression of their target genes. Here we employed a novel target-mimicry approach for the diminution of auxin signalling regulator miRNA167 by developing mimic-transgenic lines in tobacco, to investigate the transcriptional biases of flowering-associated miRNAs in apical and floral meristematic tissues and their phenotypic implications. Recorded morpho-alterations such as uneven flowering-time phenotypes, anomalous floral organ formation, and large variations in the seed forming characteristics permitted us to determine the consequence of the extent of miR167 expression diminution accompanying the transcriptional biases of interrelated miRNAs. We demonstrate that percent diminution of miR167 gene expression is proportionally associated with both early and late flowering-time ...
Characterization of Peach TFL1 and Comparison with FT/TFL1 Gene Families of the Rosaceae
Journal of the American Society for Horticultural Science
We investigated the FT/TFL1 family of peach (Prunus persica), a gene family that regulates floral induction in annual and perennial plants. The peach terminal flower 1 gene (PpTFL1) was expressed in a developmental and tissue-specific pattern that, overall, was similar to that of TFL1 orthologs in other woody Rosaceae species. Consistent with a role as a floral inhibitor, ectopic expression of PpTFL1 in arabidopsis (Arabidopsis thaliana) delayed flowering and prolonged vegetative growth. Other members of the peach FT/TFL1 family were identified from the sequenced genome, including orthologs of flowering locus T, centroradialis, brother of ft, and mother of ft and tfl. Sequence analysis found that peach FT/TFL1 family members were more similar to orthologous genes across the Rosaceae than to each other. Together these results suggest that information on genes that regulate flowering in peach could be applied to other Rosaceae species, particularly ornamentals.
Frontiers in Plant Science, 2015
In order to develop a versatile and large SNP array for rose, we set out to mine ESTs from diverse sets of rose germplasm. For this RNA-Seq libraries containing about 700 million reads were generated from tetraploid cut and garden roses using Illumina paired-end sequencing, and from diploid Rosa multiflora using 454 sequencing. Separate de novo assemblies were performed in order to identify single nucleotide polymorphisms (SNPs) within and between rose varieties. SNPs among tetraploid roses were selected for constructing a genotyping array that can be employed for genetic mapping and marker-trait association discovery in breeding programs based on tetraploid germplasm, both from cut roses and from garden roses. In total 68,893 SNPs were included on the WagRhSNP Axiom array. Next, an orthology-guided assembly was performed for the construction of a non-redundant rose transcriptome database. A total of 21,740 transcripts had significant hits with orthologous genes in the strawberry (Fragaria vesca L.) genome. Of these 13,390 appeared to contain the full-length coding regions. This newly established transcriptome resource adds considerably to the currently available sequence resources for the Rosaceae family in general and the genus Rosa in particular.
Peach: The Model Genome for Rosaceae
International Symposium on Tropical and Subtropical Fruits, 2002
For genome comparative studies and identification of important genes, it is critical to have adequate genomic resources in key model species. These resources include saturated genetic maps, large-insert genomic libraries, and physicalmaps that are integrated with the genetic maps. Such resources exist for Brassicaceae (Arabidopsis), Solanaceae (tomato) and the Poaceae (rice), but not for Rosaceae. In Rosaceae, we are building genomic resources in a tree species (peach) with a genome size only twice that of Arabidopsis. Our goal is to develop peach as a model for identification, characterization, and cloning of important genes of Rosaceae species. Consequently, we have produced saturated molecular marker linkage maps in several peach crosses segregating for important traits, both simple and complex. Because fruit quality is the single most important character to scion breeders, we have concentrated on mapping important fruit quality traits. The mapped molecular markers serve as landmarks for isolation of genes associated with important traits, and facilitate their maintenance during introgression of other tree characters, such as disease and pest resistance. They can also be used to align genetic maps in related species, facilitating gene marking and gene discovery. We are constructing a BAC physical map for peach and are integrating this map with genetic maps from other Rosaceae and key model species. These initial physical mapping studies will be presented.