Project description:Morphological identification of Pedicularis depends on floral characters. However, some important characters may be lost during the process of pressing the specimen. Pedicularis delavayi was described from northwestern Yunnan, and widely adopted as a variety of P. siphonantha. Unfortunately, the name "P. siphonantha var. delavayi' incorrectly referred to P. milliana (a new species described in this study) or P. tenuituba in some herbarium specimens and publications. Moreover, phylogenetic relationships among P. delavayi, P. siphonantha and its allies (P. milliana and P. tenuituba) were not fully resolved. In this study, we sampled 76 individuals representing 56 taxa. Of them, 10 taxa were from P. siphonantha lineage, and 11 individuals of P. delavayi represented 9 populations. These species were named as P. siphonantha group on the basis of morphological similarity. Nuclear ribosomal internal transcribed spacer (nrITS) and four chloroplast genes/regions were used for phylogenetic analyses. Phylogenetic analyses showed that the P. siphonantha group was polyphyletic: P. delavayi was sister to P. obliquigaleata in clade A; and the remaining species of P. siphonantha group were monophyletic in clade B, named as P. siphonantha lineage. In the P. siphonantha lineage, P. milliana, P. siphonantha, and P. tenuituba were well supported as monophyletic, and P. dolichosiphon was sister to P. leptosiphon. Morphologically, P. delavayi differs from species of the P. siphonantha lineage in having a long petiole (~ 50 mm) and pedicel (~ 40 mm), a ridged corolla tube, and a folded lower-lip of the corolla. Therefore, both morphological characters and phylogenetic evidence strongly supported to reinstate P. delavayi as an independent species and describe P. milliana as new species. In addition, P. neolatituba was proposed to reduce as a new synonymy of P. delavayi.
Project description:Flower opening is important for successful pollination in many plant species, and some species repeat reversible flower opening and closing movements. This is thought to be due to the turgor pressure change caused by the water influx/efflux, which depends on osmotic oscillation in the cells. In some ornamental plants, it has been suggested that water channel aquaporin may play an important role in flower opening. However, the molecular mechanism(s) involved in flower movement are largely unknown. Using Gentiana flowers, which show reversible movement in response to temperature and light stimuli, as a model, we showed that reversible flower opening is regulated by aquaporin GsPIP2;2 and GsPIP2;7. In particular, phosphorylation of the C-terminal serine residue of GsPIP2;2 is important for the transport activity and correlates closely with the flower re-opening rate. Furthermore, GsPIP2;2 is phosphorylated and activated by GsCPK16, which is activated by elevated cytosolic Ca2+ levels in response to temperature and light stimuli. We propose that reversible flower opening is regulated by GsCPK16-dependent GsPIP2;2 phosphorylation and activation, with stimulus-induced calcium signals acting as triggers. CPK-dependent phosphorylation and activation of PIP2s may be one of the universal regulatory mechanisms for flower opening in plants.
Project description:Petal is not only the target of selection by horticulturalists to enhance the ornamental value of plants but also emerged as a unique model system for plant organogenesis studies. It is known that three major groups of pigments, betalains, carotenoids and anthocyanins, are responsible for the attractive natural display of flower colors. While carotenoids and betalains generally yield yellow or red colors, anthocyanins confer a diverse range of color from orange to red to violet and blue. In this study, we collected 11 species (Erysimum cheiri, Malcolmia maritime, Brassica oleracea, Raphanus sativus, Orychophragmus violaceus, Eruca sativa, Orychophragmus violaceus, Iberis amara, Aubrieta x cultorum, Lobularia maritime, Matthiola incana) belong to different tribe in Brassicaceae family with varied flower color and performed petal transcriptome analysis. de novo transcriptome assembly showed that average length of the contigs varied from 631bp in O. violaceus to 1212bp in Matthiola incana which indicated that the complexity of the genomes are different much. Protein homology between these species and those sequenced species in Brassicaceae family are consistent with the known phylogenetic relationships. However, O. violaceus has closer relationships with Sisymbrium irio than expected Brassica species. Clustering analysis of genes in anthocyanin and carotenoids synthesis pathway indicated that while silence or low expression of CCD4 (Carotenoid Cleavage Dioxygenase 4) leading to the yellow color formation in different species, purple or red color variation might result from different genes expression variation. These results not only provide transcriptome data for petal development study but also provide useful information for Brassica flower improvement for ornamental purpose.
Project description:Flower phenotypes in the species Diplacus aurantiacus in Southern California along an east west transect range from large, yellow, insect-pollinated flowers through orange flowers to small, red, bird-pollinated flowers. Until now, intermediate forms were attributed to recurrent hybridization at the (sub)-species level. However, by monitoring the flower phenotypes of these populations in field studies over the past 20 years, Rolf Baumberger observed that the transition in flower phenotype occurs during the lifespan of individual long-lived plants, thus ruling out a hybrid origin of intermediate forms. Further research has revealed that this transition bears the hallmark of an epigenetic transition. The small, red, bird-pollinated state is stable and heritable but reverts at frequencies of 1-2 %, much higher than that of genetic alterations. In our first approach a comparative transcriptome analysis of individuals of both stable morphotypes, we like to unravel candidate genes involved in floral colour and morphology determination.
Project description:In deciduous fruit trees, entrance into dormancy occurs in later summer/fall, concomitantly with the shortening of day length and decrease in temperature. Generally speaking, dormancy can be divided into endodormancy, ecodormancy and paradormancy. In Prunus species flower buds, entrance into the dormant stage occurs when the apical meristem is partially differentiated; during dormancy, flower verticils continue their growth and differentiation. In this work we focused our attention on flower bud development during winter in peach. In order to understand how bud development progress is regulated during winter we integrated cytological epigenetic and chromatin genome wide data with transcriptional outputs to obtained a complete picture of the main regulatory pathways involved in endodormancy.