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![Phylogenetic relationships (modified from Roalson et al. [10]) and flower developmental stages sampled in Achimenes. a Floral morphological characters of interest are mapped onto the tips of the cladogram, including: pollination syndrome, primary flower color, corolla shape, and corolla gibbosity/presence of petal spurs. Four species were sampled for this study from across the genus and are indicated by a star. b The time-points sampled were: Bud, Stage D, and Pre-Anthesis flower buds. Bud stage was defined as pigmentation is largely absent and cells are beginning to elongate. Stage D was defined as pigmentation beginning to accumulate and the corolla begins to elongate. Pre-Anthesis stage was defined as flowers are nearly fully pigmented, the final size and shape of the flower has been determined, and the petal spur has developed from the corolla tube (as in A. patens). Scale bar equals 1 cm. All photos provided by W.R.R](publication/315465643/figure/fig1/AS:613951243051013@1523388791081/Phylogenetic-relationships-modified-from-Roalson-et-al-10-and-flower-developmental.png)
Phylogenetic relationships (modified from Roalson et al. [10]) and flower developmental stages sampled in Achimenes. a Floral morphological characters of interest are mapped onto the tips of the cladogram, including: pollination syndrome, primary flower color, corolla shape, and corolla gibbosity/presence of petal spurs. Four species were sampled for this study from across the genus and are indicated by a star. b The time-points sampled were: Bud, Stage D, and Pre-Anthesis flower buds. Bud stage was defined as pigmentation is largely absent and cells are beginning to elongate. Stage D was defined as pigmentation beginning to accumulate and the corolla begins to elongate. Pre-Anthesis stage was defined as flowers are nearly fully pigmented, the final size and shape of the flower has been determined, and the petal spur has developed from the corolla tube (as in A. patens). Scale bar equals 1 cm. All photos provided by W.R.R
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![Fig. 1 Phylogenetic relationships (modified from Roalson et al. [10])...](publication/315465643/figure/fig1/AS:613951243051013@1523388791081/Phylogenetic-relationships-modified-from-Roalson-et-al-10-and-flower-developmental_Q320.jpg)
Background
Flowers have an amazingly diverse display of colors and shapes, and these characteristics often vary significantly among closely related species. The evolution of diverse floral form can be thought of as an adaptive response to pollination and reproduction, but it can also be seen through the lens of morphological and developmental const...
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... this pattern in these two species, we might hypothesize that the candidate R2R3-Mybs are involved in transcriptional regulation of the ABP to produce delphini- din pigments. This is what we would expect given the blue and purple flower color in these species. In A. misera, one candidate R2R3-Myb was coexpressed with ANS and might be involved in regulating more downstream parts of the ABP (Additional file ...
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... regulation of carotenoid pigmentation in flowers is less well understood than the regulation of the ABP. An R2R3-Myb transcription factor, Reduced Carotenoid Pigmentation 1 (RCP1), has been the only transcription factor identified to be involved in flower-specific caroten- oid biosynthesis [95]. Our analyses identified 9 transcripts with similarity to RCP1 (Additional file 11). However, when we look at patterns of coexpression we only find one candidate (in A. erecta) being coexpressed with any of the enzymes of the CBP (Additional file 19). Future genetic experiments will be important to elucidating the transcriptional regulation of this network in Achimenes flowers. So far, we have identified potential candidate transcription factors, but their specific function will need to be further ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... shape in Achimenes can take many forms, including funnelform, salverform, tubular, and a number of inter- mediate forms (Fig. 1). Primary flower color is also quite variable and is represented by flowers of white, purple, pink, red, blue, and yellow colors (Fig. 1). We chose to sample species broadly across Achimenes for the present study in order to develop initial resources for understanding the genomic basis for flower diversification. Our sampling includes A. cettoana, a butterfly pollinated species with purple-blue salverform flowers (Fig. 1), A. erecta, a hum- mingbird pollinated species with red salverform flowers ( Fig. 1), A. misera, a bee pollinated species with small, white funnelform flowers with a purple throat (Fig. 1), and A. patens, a butterfly pollinated species with large, purple- pink salverform flowers and a noticeable petal spur (Fig. 1). These four species represent most of the common flower shapes and colors seen in the genus, and while they do not represent all of the possible floral forms, they present us with a starting point to guide future studies. Vouchers of each sampled species are deposited in the WR herbarium with the following identification numbers: A. cettoana, WR0155; A. erecta, WR0156; A. misera, WR0157; A. patens, ...
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... species of Achimenes (including A. patens) exhibit a unique spur-like outgrowth of the petal tube that extends in opposition to the tube opening (Fig. 1). This petal spur has evolved independently at least three times in Achimenes, mostly in butterfly-pollinated species where the flower is presented at a downward angle (Fig. 1). The purpose of this petal spur in Achimenes has yet to be elucidated; it differs from the spurs in other lineages (such as columbines, Aquilegia) by not containing nectary tissue [10]. The genetic factors influencing the development of spurs have not yet been fully understood. Recent transcrip- tome sequencing of developing spur tissue in Aquilegia identified several candidate genes for this process, including homologs of TCP4, GRF1, and many other genes that contribute to cell proliferation and auxin signaling [37]. We see an increased level of gene expression for TCP4 in A. patens in the stages where spur growth is seen while this gene in the other three species remains much lower (Fig. 4). We also see an increase in gene expression of STY1 and ARF8 in A. patens, similar to what was reported in Aquilegia (Fig. 4). With the patterns seen in A. patens relative to the other species, we can hypothesize that TCP4 may be playing a significant role in the development of the petal spur. KNOX genes, particularly STM, have also been hypothesized to be important players in petal spur devel- opment in Antirrhinum and Linaria [78,79]. Overexpres- sion of KNOX genes in Antirrhinum produced spur-like outgrowths in the floral tube [78], while KNOX genes in Linaria displayed increased expression in petal spur tissue [79]. Our expression estimates for STM across Achimenes do not offer as clear a pattern as TCP4; STM gene expres- sion patterns are similar across several species (Fig. 4). The pattern of STM expression is similar in both A. patens and A. misera (Fig. 4). Testing the functional roles of TCP4 and STM will be important in future work to determining which is more likely to be important for petal spur growth in ...
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... species of Achimenes (including A. patens) exhibit a unique spur-like outgrowth of the petal tube that extends in opposition to the tube opening (Fig. 1). This petal spur has evolved independently at least three times in Achimenes, mostly in butterfly-pollinated species where the flower is presented at a downward angle (Fig. 1). The purpose of this petal spur in Achimenes has yet to be elucidated; it differs from the spurs in other lineages (such as columbines, Aquilegia) by not containing nectary tissue [10]. The genetic factors influencing the development of spurs have not yet been fully understood. Recent transcrip- tome sequencing of developing spur tissue in Aquilegia identified several candidate genes for this process, including homologs of TCP4, GRF1, and many other genes that contribute to cell proliferation and auxin signaling [37]. We see an increased level of gene expression for TCP4 in A. patens in the stages where spur growth is seen while this gene in the other three species remains much lower (Fig. 4). We also see an increase in gene expression of STY1 and ARF8 in A. patens, similar to what was reported in Aquilegia (Fig. 4). With the patterns seen in A. patens relative to the other species, we can hypothesize that TCP4 may be playing a significant role in the development of the petal spur. KNOX genes, particularly STM, have also been hypothesized to be important players in petal spur devel- opment in Antirrhinum and Linaria [78,79]. Overexpres- sion of KNOX genes in Antirrhinum produced spur-like outgrowths in the floral tube [78], while KNOX genes in Linaria displayed increased expression in petal spur tissue [79]. Our expression estimates for STM across Achimenes do not offer as clear a pattern as TCP4; STM gene expres- sion patterns are similar across several species (Fig. 4). The pattern of STM expression is similar in both A. patens and A. misera (Fig. 4). Testing the functional roles of TCP4 and STM will be important in future work to determining which is more likely to be important for petal spur growth in ...
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... Achimenes, multiple transitions from blue to red exist [10], and there also exists at least one likely red-to-blue flower color transition on the branch leading to A. cettoana (Fig. 1). This type of transition is exceedingly rare in plants and has few documented explanations. The transition of blue-to-red is more common and often involves predict- able changes to key enzymes of the ABP, including DFR, F3′H, and F3′5′H (see Discussion above). One such case of red-to-blue flower color transition involves a gene duplication of F3′H and neofunctionalization to regain the role of F3′5′H in Asteraceae [92,93]. A similar gene dupli- cation event is not found when the gene trees are examined for F3′H and F3′5′H (Additional file 7), suggesting that changes in gene expression are more likely involved in a red-to-blue color transition in ...
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... stages of flower development were sampled so that temporal changes in gene expression could be studied. 'Immature Bud' (B) stage was the smallest flower buds that could be distinguished from vegetative buds (Fig. 1). 'Stage D' (D) were larger flower buds that were beginning to accumulate pigmentation, the cells in the corolla tube are elongating, and the petal spur (as in A. patens) is beginning to develop (Fig. 1). 'Pre-Anthesis' (A) flower buds were the largest and fully pigmented and were collected one-day before anthesis (Fig. 1). Given that the different species have different flowering times, these stages are determined from qualitative observations. Plants were grown in greenhouse conditions under natural daylight, controlled temperature ranging from 27 to 32 °C, and >80% humidity. For all experiments, plant material was harvested directly into liquid nitrogen and subse- quently stored at -80 °C. To obtain enough fresh material for RNA extraction, between 2 and 5 flower buds were sampled from an individual ...
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... stages of flower development were sampled so that temporal changes in gene expression could be studied. 'Immature Bud' (B) stage was the smallest flower buds that could be distinguished from vegetative buds (Fig. 1). 'Stage D' (D) were larger flower buds that were beginning to accumulate pigmentation, the cells in the corolla tube are elongating, and the petal spur (as in A. patens) is beginning to develop (Fig. 1). 'Pre-Anthesis' (A) flower buds were the largest and fully pigmented and were collected one-day before anthesis (Fig. 1). Given that the different species have different flowering times, these stages are determined from qualitative observations. Plants were grown in greenhouse conditions under natural daylight, controlled temperature ranging from 27 to 32 °C, and >80% humidity. For all experiments, plant material was harvested directly into liquid nitrogen and subse- quently stored at -80 °C. To obtain enough fresh material for RNA extraction, between 2 and 5 flower buds were sampled from an individual ...
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... stages of flower development were sampled so that temporal changes in gene expression could be studied. 'Immature Bud' (B) stage was the smallest flower buds that could be distinguished from vegetative buds (Fig. 1). 'Stage D' (D) were larger flower buds that were beginning to accumulate pigmentation, the cells in the corolla tube are elongating, and the petal spur (as in A. patens) is beginning to develop (Fig. 1). 'Pre-Anthesis' (A) flower buds were the largest and fully pigmented and were collected one-day before anthesis (Fig. 1). Given that the different species have different flowering times, these stages are determined from qualitative observations. Plants were grown in greenhouse conditions under natural daylight, controlled temperature ranging from 27 to 32 °C, and >80% humidity. For all experiments, plant material was harvested directly into liquid nitrogen and subse- quently stored at -80 °C. To obtain enough fresh material for RNA extraction, between 2 and 5 flower buds were sampled from an individual ...
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... in flower color are one of the most distinguish- ing characters that separate Achimenes species. Flowers across the genus display an amazing array of colors and color patterns, including species with white, yellow, red, blue, and purple pigmentation [10,12] (Fig. 1). The primary pigment in flowers of Achimenes and most angiosperms are anthocyanins, a class of flavonoids that represent a large group of secondary metabolites [80]. The types of pigments present in floral tissue vary across Achimenes species, with all taxa containing anthocyanins and several containing a mix of anthocyanins and carotenoids. Anthocyanins con- tribute hues of blues, purples, and reds due primarily to production of pelargonidins, cyanidins, and delphinidins [80]. In plants, the biochemistry of the ABP is very well studied and understood in both model systems (e.g., Arabidopsis) [81] and non-model systems (e.g., Aquilegia, Mimulus, and Iochroma) [82][83][84][85][86]. While the biochemical reactions involved in the ABP are well understood, further research aims at understanding how the genetics of the pathway contributes to species differences in pigment production and the role it plays in adaptive evolution. The ABP is composed of 7 structural loci, with many of the earliest steps highly conserved in plants due to their role in producing precursor products involved in defense and UV protection [80,81] (Fig. 2). The downstream pathway splits into 3 branches that lead to production of red pelargonidins, purple cyanidins, and blue delphinidins [80]. Flux down any of these branches is largely deter- mined by the activity of two enzymes: F3′H and F3′5′H. Downregulation or inactivation of these enzymes can cause flux to be redirected down a different branch, result- ing in a different flower ...
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... is interesting to find that several of the ABP enzymes are coexpressed together and in three species (A. cettoana, A. misera, and A. patens) they are coexpressed with candi- date R2R3-Mybs that we identified (Additional file 19). In A. cettoana, the candidate R2R3-Myb is coexpressed with F3′5′H, the enzyme that directs the metabolic flux of the pathway toward the production of delphinidins (Fig. 2). Another candidate R2R3-Myb in A. patens was coex- pressed with F3H, F3′5′H, and ANS (Additional file ...
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... provide a first characterization of the floral tran- scriptomes in four species of magic flowers, Achimenes. This small genus of ~26 species is a member of the African violet family (Gesneriaceae), a large family distrib- uted in the New World and Old World tropics. The family is renowned for its enormous diversity in habit, desicca- tion tolerance, leaf morphology, and, particularly, floral form [5][6][7]. Flower shape, color, and presentation are hypothesized to be important for diversification and speci- ation events in the family [7][8][9][10][11]. Convergence in floral form is found across the family as well as in individual genera and is likely tied to pollinator preferences and pol- linator availability [7,11]. In Achimenes, floral form appears to be quite variable among closely related species and similar corolla shapes and colors are found among species that occur in different clades [10] (Fig. 1). Multiple derivations of flower shape, color, and the presence of a petal spur appear across the genus [10] (Fig. 1). Populations of Achimenes are largely concentrated in central Mexico south to Costa Rica, with some populations existing in the Caribbean. General distributions of many closely related species often overlap with many populations found growing in the same habitat and elevation ranges [12]. Pollinator studies have been limited with observations recorded for only four species of Achimenes [13]. The major pol- linator observed for each of the four Achimenes species corresponds tightly with the hypothesized pollination syndrome that was identified using combi- nations of floral traits thought to be important for pollinator attraction, such as color, shape, size, and orien- tation of the open flower [10]. The young age of the genus (~12 Ma) [7], coupled with a large number of shifts in flower shape, color, and pollination syndrome [10], makes Achimenes an ideal lineage to begin understanding the ecological, evolutionary, and molecular forces contributing to speciation and diversification of floral ...
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... provide a first characterization of the floral tran- scriptomes in four species of magic flowers, Achimenes. This small genus of ~26 species is a member of the African violet family (Gesneriaceae), a large family distrib- uted in the New World and Old World tropics. The family is renowned for its enormous diversity in habit, desicca- tion tolerance, leaf morphology, and, particularly, floral form [5][6][7]. Flower shape, color, and presentation are hypothesized to be important for diversification and speci- ation events in the family [7][8][9][10][11]. Convergence in floral form is found across the family as well as in individual genera and is likely tied to pollinator preferences and pol- linator availability [7,11]. In Achimenes, floral form appears to be quite variable among closely related species and similar corolla shapes and colors are found among species that occur in different clades [10] (Fig. 1). Multiple derivations of flower shape, color, and the presence of a petal spur appear across the genus [10] (Fig. 1). Populations of Achimenes are largely concentrated in central Mexico south to Costa Rica, with some populations existing in the Caribbean. General distributions of many closely related species often overlap with many populations found growing in the same habitat and elevation ranges [12]. Pollinator studies have been limited with observations recorded for only four species of Achimenes [13]. The major pol- linator observed for each of the four Achimenes species corresponds tightly with the hypothesized pollination syndrome that was identified using combi- nations of floral traits thought to be important for pollinator attraction, such as color, shape, size, and orien- tation of the open flower [10]. The young age of the genus (~12 Ma) [7], coupled with a large number of shifts in flower shape, color, and pollination syndrome [10], makes Achimenes an ideal lineage to begin understanding the ecological, evolutionary, and molecular forces contributing to speciation and diversification of floral ...
Citations
... Flavonoids can be divided into flavonols, flavones, isoflavones, anthocyanidins, flavanones, flavanols, and chalcones according to the structure [27] . Among them, anthocyanins are the most crucial color-developing flavonoid substances, which are closely related to flower color [28,29] . In this study, the metabolome analysis showed that the color change in lips was found to be related to the amount of flavonoids, particularly the anthocyanin content. ...
Cymbidium floribundum is an ornamental plant with showy and colorful flowers. The color of its lip changes significantly after pollination. However, the mechanism of lip coloration remains unclear. In this study, the mechanism underlying lip color change in C. floribundum was investigated before and after pollination. Metabolome analysis detected 61 flavonoids in the lip, including 24 flavonoids, 13 flavonols, nine flavonoid carbonosides, eight anthocyanins, three flavanols, two isoflavones, one chalcone, and one dihydroflavone. Accumulation of peonidin 3-O-glucoside chloride, cyanin chloride, and cyanidin 3-O-malonylhexoside after pollination may be the key factors contributing to the change in lip color. Furthermore, transcriptome analysis identified 43 genes related to the anthocyanin biosynthesis pathway (ABP). Phylogenetic and co-expression analysis indicated that CfMYB1, CfMYB3, and CfMYB4 may be involved in the regulation of anthocyanin biosynthesis in the lips. Subcellular localization results showed that CfMYB1 was located in the nucleus, while CfMYB3 and CfMYB4 were located in the nucleus and cytoplasm. Further functional analysis verified that CfMYB1 could activate ABP genes and promote the synthesis and accumulation of anthocyanin, which may be the main transcription factors leading to the change of lip color in C. floribundum after pollination. These findings provide insight into the anthocyanin accumulation and coloration mechanisms during C. floribundum flower development. The results provide genetic resources and a theoretical basis for the improvement and breeding of flower color in C. floribundum.
... Transcriptomic studies play a significant role in comparative pathway analyses within flowering research, offering valuable insight into gene expression changes, regulatory networks, and novel pathways involved in the flowering process (Guo et al. 2010;Roberts and Roalson 2017). Due to the scarcity of genetic data for these two species, our present strategy includes de novo sequencing of leaf tissues from both species. ...
The present study investigates the flower-anthesis mechanism in two closely related plant species, Cestrum diurnum and Cestrum nocturnum. These plants are morphologically similar, but exhibit distinct flowering times: C. diurnum flowers during the day, whereas C. nocturnum blooms at night. This contrast in flowering time makes them ideal subjects for this study. Physiological parameters like photosynthetic rate, floral development, and chlorophyll content were analyzed along with transcriptome sequencing. Transcripts related to blooming time were analyzed using de novo sequencing analysis, with emphasis on photoperiod, autonomous, circadian clock, and vernalization pathways. Gene Ontology and KEGG pathway enrichment analysis revealed differences in morphology and physiology. Transcription factors (bHLH, ERF, MYB, and C2H2) involved in regulating flowering time were identified between these two species. The delayed flowering of C. nocturnum was validated by qRT-PCR, which showed the involvement of FT, FLC, and CO genes. Physical attributes such as larger leaves and higher chlorophyll content were two distinctive characteristics of C. nocturnum attributed to higher PHYA levels. Explaining the different flowering events between these two species, the study implies that C. nocturnum focuses on flower formation, photoperiodic responses, and meristem management, whereas C. diurnum prioritizes growth and development.
... At the stage of colorful petal formation, genes responsible for encoding enzymes for pigment synthesis, genes involved in the synthesis of secondary metabolites in tissue, such as carotenoids or anthocyanins, were significantly upregulated in Achimenes [70]. Other gene families were involved during the development of broccoli (Brassica oleracea var. ...
Plant transcriptomes are an extremely dynamic entities shaped spatially and temporally by many intracellular and environmental cues. In this review, we first summarize the complexity and diversity of plant genomes and transcriptomes as a start point for the multitude of transcriptomic responses. Numerous alterations within various tissue and organ‐specific transcriptomes as well as the most relevant transcriptomic responses associated with plant acclimation to selected abiotic and biotic stress conditions, from the current studies employing highthroughput
transcriptomic analysis are widely discussed. Understanding changes within plant
transcriptomes, revealed by in silico functional analysis, allows for the characterization of stress affected genes and stress acclimatory mechanisms, as well as allows to perform plant metabolic engineering. The latter allow cultivars to produce more secondary metabolites in the future, which are often desirable substances in the biomedical industry. Accordingly, in this review special attention was also paid to characterize the potential of transcriptomic analyses of medicinal species, particularly to search for new cultivars. Extensive characterization of transcriptomic responses in stress would also result in the development of new cultivars that display physiological and molecular mechanisms that allow them to cope with adverse environmental conditions more adequately.
... Flowers characteristics like colors and shapes, etc., vary significantly among closely related species. In order to understand the genes involved in the three different stages of flower interaction across species in a group of Neotropical plants native to Mexico-magic flowers (Achimenes,Gesneriaceae), RNA-seq were done (Roberts and Roalson, 2017). Three stages of flower development such Immature Bud, Stage D, and Pre-Anthesis were used for RNA seq. ...
... Flowers and their color variation are one of the stunning products of evolution (Roberts and Roalson 2017) and have been investigated from different angles such as gene regulation, population genetics, reinforcement, ecological adaption and speciation (Durbin et al. 2003;Schemske and Bierzychudek 2001;Roda et al. 2017;Clegg and Durbin 2000;Hopkins and Rausher 2011). The availability of genomic resources has contributed to advances in some model species but studies about the genetic control of flower color variation in non-model species have been rare due to the lack of genome wide data. ...
... Flower color is one of the most important traits in angiosperms. Understanding the underlying mechanisms of flower color variation may help us to better understand plant evolution and adaptation (Roberts and Roalson 2017;Clegg and Durbin 2000). Here, we used transcriptome sequencing of the two flower color types (yellowish-white and fuchsia) in the R. palmatum complex, the basis of which is still poorly understood in the genus Rheum. ...
Flower color variation is ubiquitous in many plant species, and several studies have been conducted to elucidate the underlying molecular mechanism. There are two flower color variants (yellowish-white and fuchsia) in the Rheum palmatum complex, however, few studies have investigated this phenomenon. Here, we used transcriptome sequencing of the two color variants to shed light on the molecular and biochemical basis for these color morphs. Comparison of the two transcriptomes identified 9641 differentially expressed unigenes (DEGs), including 6477 up-regulated and 3163 down-regulated genes. Functional analyses indicated that several DEGs were related to the anthocyanin biosynthesis pathway, and the expression profiles of these DEGs were coincident with the qRT-PCR validation results, indicating that expression levels of structural genes have a profound effect on the color variation in the R. palmatum complex. Our results suggested that the interaction of transcription factors (MYB, bHLH and WRKY) also regulated the anthocyanin biosynthesis in the R. palmatum complex. Estimation of selection pressures using the dN/dS ratio showed that 1106 pairs of orthologous genes have undergone positive selection. Of these positively selected genes, 21 were involved in the anthocyanin biosynthetic pathway, indicating that they may encode the proteins for structural alteration and affect flower color in the R. palmatum complex.
... Other aspects limiting the power of this approach are the relatively few genes associated with floral development in the Gene Ontology database, that it could not consider genes that are not expressed at all in the flower tissues in one of the species, and that it only focusses on protein variants and as such will miss genes which expression is affected by cis-regulatory regions. Although this approach did not result in a strong candidate gene to explain corolla shape, it might represent an interesting approach to find sequences of interest in non-model species, especially when the genetic bases of a trait are not very well defined as with floral shape [109]. For future studies, differential gene expression, which was not possible here given the nature of our transcriptomes, might provide more candidates. ...
Floral adaptations to specific pollinators like corolla shape variation often result in reproductive isolation and thus speciation. But despite their ecological importance, the genetic bases of corolla shape transitions are still poorly understood, especially outside model species. Hence, our goal was to identify candidate genes potentially involved in corolla shape variation between two closely related species of the Rhytidophyllum genus (Gesneriaceae family) from the Antilles with contrasting pollination strategies. Rhytidophyllum rupincola has a tubular corolla and is strictly pollinated by hummingbirds, whereas R. auriculatum has more open flowers and is pollinated by hummingbirds, bats, and insects. We surveyed the literature and used a comparative transcriptome sequence analysis of synonymous and non-synonymous nucleotide substitutions to obtain a list of genes that could explain floral variation between R. auriculatum and R. rupincola. We then tested their association with corolla shape variation using QTL mapping in a F2 hybrid population. Out of 28 genes tested, three were found to be good candidates because of a strong association with corolla shape: RADIALIS, GLOBOSA, and JAGGED. Although the role of these genes in Rhytidophyllum corolla shape variation remains to be confirmed, these findings are a first step towards identifying the genes that have been under selection by pollinators and thus involved in reproductive isolation and speciation in this genus.
... Plant pigments have attracted wide attention in recent years, and considerable progress has been made in determining their synthesis and regulation mechanisms. Significant phenotypic differences in floral color may be caused by minor genetic differences (Roberts and Roalson 2017). Thus far, several mutants of the anthocyanin pathway have been characterized. ...
Main conclusion
SmANS deletion leads to white flower mutation in Salvia miltiorrhiza.
Abstract
SmANS deletion leads to white flower mutation in Salvia miltiorrhiza. Abstract Salvia miltiorrhiza is an essential traditional Chinese medicine (TCM) with purple flowers, and S. miltiorrhiza Bge. f. alba is a unique intraspecific variation with white flowers. The molecular mechanism of flower color formation in S. miltiorrhiza will provide vital information for the variation and evolution. Here, we performed HPLC, transcriptomic, and re-sequencing analyses of purple-flowered S. miltiorrhiza line ‘Zihua105’ (ZH105) and white-flowered S. miltiorrhiza Bge. f. alba line ‘Baihua18’ (BH18). Delphinidin was the most anthocyanidin in ZH105, which become the main different between ZH105 vs. BH18 flowers. Transcriptome analysis revealed 299 differentially expressed genes (DEGs). SmANS, the anthocyanidin synthase gene in the down-stream anthocyanin biosynthesis pathway, was significantly expressed in ZH105 corollas, suggesting it might play a key role in white petal formation. Whole-genome re-sequencing revealed that a 6.75 kb segment located on chromosome 5, which contains the complete sequence of the SmANS genes, was lost in BH18 and another S. miltiorrhiza Bge. f. alba line. In contrast, the other five purple-flowered S. miltiorrhiza lines both possessed this segment. Further molecular marker identification also confirmed that wild S. miltiorrhiza Bge. f. alba lines lost regions that contained a complete or important part of SmANS sequences. Subsequently, the research showed that the deletion mutant of SmANS genes resulted in the natural white flower color variant of S. miltiorrhiza.
... The elucidation of the developmental mechanisms underlying different flowering patterns is critical for a comprehensive understanding of the diversification of flowers, which has been exemplified in studies on Cicer arietinum [58], Annona squamosa [59], Achimenes [60], Rhododendron pulchrum [61], and Zingiber zerumbet [62]. Similar to the results of these studies, we found carbohydrate metabolism and photosynthesis to play important roles during flower morphogenesis in petunia. ...
... Flavonoids have also been proven to be essential for pollen tube growth and pollen function [75]. In our study, we found that the genes regulating phenylalanine-related pathways, including flavonoid biosynthesis, phenylpropanoid biosynthesis, and phenylalanine metabolism, were up-regulated during the flower developmental stages; similar metabolic pathways have been observed in many plant species [58,60,61,76], suggesting the involvement of secondary metabolites in some developmental events occurring in various stages. However, the molecular mechanism underlying the appearance and enrichment of metabolites in flower development remains nebulous, which might be due to the stage-specific expression of TF family members, such as the genes in subgroup 7 of R2R3 MYB and the subgroup bHLH IIIf and III(d+e), which play important roles in flavonoid biosynthesis in many plants [77][78][79]. ...
Published genome sequences can facilitate multiple genome sequencing studies of flower development, which can serve as the basis for later analysis of variation in flower phenotypes. To identify potential regulators related to flower morphology, we captured dynamic expression patterns under five different developmental stages of petunia flowers, a popular bedding plant, using transcriptome and miRNA sequencing. The significant transcription factor (TF) families, including MYB, MADS, and bHLH, were elucidated. MADS-box genes exhibited co-expression patterns with BBR-BPC, GATA, and Dof genes in different modules according to a weighted gene co-expression network analysis. Through miRNA sequencing, a total of 45 conserved and 26 novel miRNAs were identified. According to GO and KEGG enrichment analysis, the carbohydrate metabolic process, photosynthesis, and phenylalanine metabolism were significant at the transcriptomic level, while the response to hormone pathways was significantly enriched by DEmiR-targeted genes. Finally, an miRNA–RNA network was constructed, which suggested the possibility of novel miRNA-mediated regulation pathways being activated during flower development. Overall, the expression data in the present study provide novel insights into the developmental gene regulatory network facilitated by TFs, miRNA, and their target genes.
... This research has been conducted with the purpose of changing flower colors and creating new ones in African violet species. Flower and ornamental plants industry has been trying to develop new cultivars with specific characteristics such as new colors [20]. The development of ornamental cultivars with new flower colors, considering the major purpose of flower and ornamental plants industry, will result in increased economic value [21]. ...
Background
Flower color is one of the main characteristics of ornamental plants. Aurones are light yellow flavonoids produced in the petals of a limited number of plant species including snapdragon ( Antirrhinum majus ). As a commercially-recognized species, African violet can be found in various colors except yellow. This research, aiming at changing the petals’ color of African violet from white to yellow, was conducted using the simultaneous expressions of chalcone 4’- O -glucosyltransferase ( 4’CGT ) and aureusidin synthase ( AS1 ) genes without the need for silencing anthocyanin biosynthesis pathway genes via both transient and stable transfer methods.
Results
The transient gene transfer among transgenic plants led to a clear change of petals’ color from white to light yellow. This occurs while no change was observed in non-transgenic (Wild type) petals. In total, 15 positive transgenic plants, produced via stable gene transfer, were detected. Moreover, since their flower color was yellow, both genes were present. Meanwhile, the corresponding transformation yield was determined 20-30%. The transformation, expression and integration of genes among T0 transgenic plants were verified using the PCR, qRT-PCR and Southern blotting techniques, respectively. Furthermore, the probable color change of petals’ cross-section and existence of Aureusidin 6- O -glucoside ( AOG ) compound were determined using a light microscope and HPLC-DAD-MSn analysis, correspondingly.
Conclusions
Generally, the creation of aurones biosynthesis pathway is only viable through the simultaneous expression of genes which leads to color change of African violet’s petal from white to yellow. This conclusion can lead to an effective strategy to produce yellow color in ornamental plant species.
... These genes were found to be the most similar to ABCB1 or 19 when compared to databases. ABCB1 and 19 are auxin efflux carriers involved in the accumulation of anthocyanin [93,94]. However, Interproscan analysis indicated that the proteins produced by these three genes do not have the complete ABCB structural domain. ...
Zoysia japonica is a warm-season turfgrass that is extensively used in landscaping, sports fields, and golf courses worldwide. Uncovering the low-temperature response mechanism of Z. japonica can help to accelerate the development of new cold-tolerant cultivars, which could be used to prolong the ornamental and usage duration of turf. A novel Z. japonica biotype, YueNong-9 (YN-9), was collected from northeastern China for this study. Phenotypic measurements, cold-tolerance investigation, and whole-transcriptome surveys were performed on YN-9 and LanYin-3 (LY-3), the most popular Z. japonica cultivar in Southern China. The results indicated the following: YN-9 has longer second and third leaves than LY-3; when exposed to the natural low temperature during winter in Guangzhou, YN-9 accumulated 4.74 times more anthocyanin than LY-3; after cold acclimation and freezing treatment, 83.25 ± 9.55% of YN-9 survived while all LY-3 leaves died, and the dark green color index (DGCI) value of YN-9 was 1.78 times that of LY-3; in YN-9, there was a unique up-regulation of Phenylalanine ammonia-lyase (PAL), Homeobox-leucine Zipper IV (HD-ZIP), and ATP-Binding Cassette transporter B8 (ABCB8) expressions, as well as a unique down-regulation of zinc-regulated transporters and iron-regulated transporter-like proteins (ZIPs) expression, which may promote anthocyanin biosynthesis, transport, and accumulation. In conclusion, YN-9 exhibited enhanced cold tolerance and is thus an excellent candidate for breeding cold-tolerant Z. japonica variety, and its unique low-temperature-induced anthocyanin accumulation and gene responses provide ideas and candidate genes for the study of low-temperature tolerance mechanisms and genetic engineering breeding.
