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The petal blight disease of alpine Rhododendron severely impacts the ornamental and economic values of Rhododendron. Plant secondary metabolites play a crucial role in resisting pathogenic fungi, yet research on metabolites in alpine Rhododendron petals that confer resistance to pathogenic fungi is limited. In the present study, the secondary metabolites in Rhododendron delavayi, R. agastum, and R. irroratum petals with anti-pathogenic activity were screened through disease index analysis, metabolomic detection, the mycelial growth rate, and metabolite spraying experiments. Disease index analysis revealed that R. delavayi petals exhibited the strongest disease resistance, while R. agastum showed the weakest, both under natural and experimental conditions. UHPLC-QTOF-MS/MS analysis identified 355 and 274 putative metabolites in positive and negative ion modes, respectively. The further antifungal analysis of differentially accumulated baicalein, diosmetin, and naringenin showed their half-inhibitory concentrations (IC50) against Neopestalotiopsis clavispora to be 5000 mg/L, 5000 mg/L, and 1000 mg/L, respectively. Spraying exogenous baicalein, diosmetin, and naringenin significantly alleviated petal blight disease caused by N. clavispora infection in alpine Rhododendron petals, with the inhibition rates exceeding 64%. This study suggests that the screened baicalein, diosmetin, and naringenin, particularly naringenin, can be recommended as inhibitory agents for preventing and controlling petal blight disease in alpine Rhododendron.
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Flavonoides , Flores , Enfermedades de las Plantas , Rhododendron , Rhododendron/microbiología , Rhododendron/química , Flavonoides/farmacología , Flavonoides/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Flores/microbiología , Espectrometría de Masas en Tándem , Resistencia a la Enfermedad , Metabolómica/métodos , Antifúngicos/farmacología , Ascomicetos/efectos de los fármacos , Ascomicetos/patogenicidadRESUMEN
BACKGROUND: Saffron petals are usually considered as waste after saffron harvest. However, saffron petals contain many important phytochemical components (e.g. quercetin and kaempferol), which may alleviate oxidative damage in human cells. RESULTS: The contents of flavonoids and crocin in different parts of saffron were analyzed. The protective effects of flavonoids from saffron on oxidative damage of B16 cells were investigated. Saffron stigma contained high contents of crocin and picrocrocin, whereas flavonoid content (quercetin, 4.03 ± 0.33 mg g-1 DW; kaempferol, 47.80 ± 0.60 mg g-1 DW) was higher in saffron petals than in other parts. Incubation of B16 cells with quercetin (10-30 µmol L-1) and kaempferol (20-30 µmol L-1) obtained from saffron extracts could significantly increase the total antioxidant capacity (T-AOC) and the activity of NADPH:dehydrogenase quinone-1 (NQO1) to alleviate H2O2-induced oxidative damage. Quercetin was better than kaempferol in increasing NQO1 activity and T-AOC. Quercetin extracted from saffron petals could induce NQO1 expression through regulating kelch-like ECH-associated protein-1/nuclear factor erythroid 2-related factor-2 signaling pathway to protect B16 cells from oxidative damage. CONCLUSION: The content of kaempferol-3-O-sophoroside and quercetin-3-O-sophoroside was higher in saffron petals than in other parts of saffron. The kaempferol and quercetin obtained from saffron petals could enhance the activity of antioxidant enzyme NQO1 and T-AOC in B16 cells. This indicated that saffron petals, as a potential functional food, may prevent diseases caused by oxidative stress. © 2024 Society of Chemical Industry.
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Rosa rugosa is limited in landscaping applications due to its monotonous color, especially the lack of red-flowered varieties. Comprehensive assessment of petal color diversity in R. rugosa could promote to explore the mechanism of flower color formation. In this study, the variation and diversity of petal coloring of 193 R. rugosa germplasms were assessed by chromatic values (L∗, a∗, and b∗), and then divided into seven clusters belonging to three groups with pinkish-purple (185 individuals), white (6), and red (2) petals, respectively. Total anthocyanin content was the most important factor affecting flower color diversity and red hue formation of R. rugosa petals. There were significant correlations between petal color chromatic indexes and the sum content and the ratio of two major anthocyanin, namely cyanidin 3,5-O-diglucoside (Cy3G5G), peonidin 3,5-O-diglucoside (Pn3G5G). Both high levels of Cy3G5G + Pn3G5G and Cy3G5G/Pn3G5G were necessary conditions for red phenotype formation. Five cyanidin up-stream structural genes (RrF3'H1, RrDFR1, RrANS1, RrUF3GT1, RrUF35GT1) and one cyanidin down-stream structural gene (RrCCoAOMT1) were the key indicators which contributed to Cy3G5G + Pn3G5G and Cy3G5G/Pn3G5G, respectively. Functional verification showed that overexpression of RrDFR1, combined with silent expression of RrCCoAOMT1, could make R. rugosa petals redder by increasing the levels of Cy3G5G + Pn3G5G and Cy3G5G/Pn3G5G. These results provided a robust theoretical basis for further revealing the molecular mechanism of red petals coloration in R. rugosa.
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Rose (Rosa sp.) is one of the most important ornamentals which is commercialize for its aesthetic values, essential oils, cosmetic, perfume, pharmaceuticals and food industries in the world. It has wide range of variations that is mostly distinguished by petal color differences which is interlinked with the phytochemicals, secondary metabolites and antinutrient properties. Here, we explored the color, bioactive compounds and antinutritional profiling and their association to sort out the most promising rose genotypes. For this purpose, we employed both quantitative and qualitative evaluation by colorimetric, spectrophotometric and visual analyses following standard protocols. The experiment was laid out in randomized complete block design (RCBD) with three replications where ten rose genotypes labelled R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 were used as plant materials. Results revealed in quantitative assessment, the maximum value of lightness, and the luminosity indicating a brightening of rose petals close to a yellow color from rose accessions R4, and R10, respectively which is further confirmed with the visually observed color of the respective rose petals. Proximate composition analyses showed that the highest amount of carotenoid and ß-carotene was found in R10 rose genotype, anthocyanin and betacyanin in R7. Among the bioactive compounds, maximum tocopherol, phenolic and flavonoid content was recorded in R8, R6 and R3 while R1 showed the highest free radical scavenging potentiality with the lowest IC50 (82.60 µg/mL FW) compared to the others. Meanwhile, the enormous variation was observed among the studied rose genotypes regarding the antinutrient contents of tannin, alkaloid, saponin and phytate whereas some other antinutrient like steroids, coumarines, quinones, anthraquinone and phlobatanin were also figured out with their presence or absence following qualitative visualization strategies. Furthermore, according to the Principal Component Analysis (PCA), correlation matrix and cluster analysis, the ten rose genotypes were grouped into three clusters where, cluster-I composed of R3, R4, R5, R8, cluster-II: R9, R10 and cluster-III: R1, R2, R6, R7 where the rose genotypes under cluster III and cluster II were mostly contributed in the total variations by the studied variables. Therefore, the rose genotypes R9, R10 and R1, R2, R6, R7 might be potential valuable resources of bioactive compounds for utilization in cosmetics, food coloration, and drugs synthesis which have considerable health impact.
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Fitoquímicos , Rosa , Rosa/química , Fitoquímicos/análisis , Genotipo , Antioxidantes/análisis , Color , Flores/químicaRESUMEN
The cotton genus comprises both diploid and allotetraploid species, and the diversity in petal colour within this genus offers valuable targets for studying orthologous gene function differentiation and evolution. However, the genetic basis for this diversity in petal colour remains largely unknown. The red petal colour primarily comes from C, G, K, and D genome species, and it is likely that the common ancestor of cotton had red petals. Here, by employing a clone mapping strategy, we mapped the red petal trait to a specific region on chromosome A07 in upland cotton. Genomic comparisons and phylogenetic analyses revealed that the red petal phenotype introgressed from G. bickii. Transcriptome analysis indicated that GhRPRS1, which encodes a glutathione S-transferase, was the causative gene for the red petal colour. Knocking out GhRPRS1 resulted in white petals and the absence of red spots, while overexpression of both genotypes of GhRPRS1 led to red petals. Further analysis suggested that GhRPRS1 played a role in transporting pelargonidin-3-O-glucoside and cyanidin-3-O-glucoside. Promoter activity analysis indicated that variations in the promoter, but not in the gene body of GhRPRS1, have led to different petal colours within the genus. Our findings provide new insights into orthologous gene evolution as well as new strategies for modifying promoters in cotton breeding.
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INTRODUCTION: Green flowers are not an adaptive trait in natural plants due to the challenge for pollinators to discriminate from leaves, but they are valuable in horticulture. The molecular mechanisms of green petals remain unclear. Tree peony (Paeonia suffruticosa) is a globally cultivated ornamental plant and considered the 'King of Flowers' in China. The P. suffruticosa 'Lv Mu Yin Yu (LMYY)' cultivar with green petals could be utilized as a representative model for understanding petal-specific chlorophyll (Chl) accumulation and color formation. OBJECTIVES: Identify the key genes related to Chl metabolism and understand the molecular mechanism of petal color changes. METHODS: The petal color parameter was analyzed at five developmental stages using a Chroma Spectrophotometer, and Chl and anthocyanin accumulation patterns were examined. Based on comparative transcriptomes, differentially expressed genes (DEGs) were identified, among which three were functionally characterized through overexpression in tobacco plants or silencing in 'LMYY' petals. RESULTS: During flower development and blooming, flower color changed from green to pale pink, consistent with the Chl and anthocyanin levels. The level of Chl demonstrated a similar pattern with petal epidermal cell striation density. The DEGs responsible for Chl and anthocyanin metabolism were characterized through a comparative transcriptome analysis of flower petals over three critical developmental stages. The key chlorophyllase (PsCLH1) and light-harvesting chlorophyll a/b binding protein 1 (PsLhcb1) and PsLhcb5 influenced the Chl accumulation and the greenness of 'LMYY' petals. CONCLUSION: PsCLH1, PsLhcb1, and PsLhcb5 were critical in accumulating the Chl and maintaining the petal greenness. Flower color changes from green to pale pink were regulated by the homeostasis of Chl degradation and anthocyanin biosynthesis. This study offers insights into underlying molecular mechanisms in the green petal and a strategy for germplasm innovation.
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Petal size, a crucial trait in the economically important ornamental rose (Rosa hybrida), is synergistically regulated by cell division and cell expansion. Cell division primarily occurs during the early development of petals. However, the molecular mechanism underlying the regulation of petal size is far from clear. In this study, we isolated the transcription factor gene RhSCL28, which is highly expressed at the early stage of rose petal development and is induced by cytokinin. Silencing RhSCL28 resulted in a reduced final petal size and reduced cell number in rose petals. Further analysis showed that RhSCL28 participates in the regulation of cell division by positively regulating the expression of the cyclin genes RhCYCA1;1 and RhCYCB1;2. To explore the potential mechanism for cytokinin-mediated regulation of RhSCL28 expression, we investigated the cytokinin response factor RhRR1 and determined that it positively regulates RhSCL28 expression. Like RhSCL28, silencing RhRR1 also resulted in smaller petals by decreasing cell number. Taken together, these results reveal that the RhRR1-RhSCL28 module positively regulates petal size by promoting cell division in rose.
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Blotches in floral organs attract pollinators and promote pollination success. Tree peony (Paeonia suffruticosa Andr.) is an internationally renowned cut flower with extremely high ornamental and economic value. Blotch formation on P. suffruticosa petals is predominantly attributed to anthocyanin accumulation. However, the endogenous regulation of blotch formation in P. suffruticosa remains elusive. Here, we identified the regulatory modules governing anthocyanin-mediated blotch formation in P. suffruticosa petals, which involves the transcription factors PsMYB308, PsMYBPA2, and PsMYB21. PsMYBPA2 activated PsF3H expression to provide sufficient precursor substrate for anthocyanin biosynthesis. PsMYB21 activated both PsF3H and PsFLS expression and promoted flavonol biosynthesis. The significantly high expression of PsMYB21 in non-blotch regions inhibited blotch formation by competing for anthocyanin biosynthesis substrates, while conversely, its low expression in the blotch region promoted blotch formation. PsMYB308 inhibited PsDFR and PsMYBPA2 expression to directly prevent anthocyanin-mediated blotch formation. Notably, a smaller blotch area, decreased anthocyanin content, and inhibition of anthocyanin structural gene expression were observed in PsMYBPA2-silenced petals, while the opposite phenotypes were observed in PsMYB308-silenced and PsMYB21-silenced petals. Additionally, PsMYBPA2 and PsMYB308 interacted with PsbHLH1-3, and their regulatory intensity on target genes was synergistically regulated by the PsMYBPA2-PsbHLH1-3 and PsMYB308-PsbHLH1-3 complexes. PsMYB308 also competitively bound to PsbHLH1-3 with PsMYBPA2 to fine-tune the regulatory network to prevent overaccumulation of anthocyanin in blotch regions. Overall, our study uncovers a complex R2R3-MYB transcriptional regulatory network that governs anthocyanin-mediated blotch formation in P. suffruticosa petals, providing insights into the molecular mechanisms underlying blotch formation in P. suffruticosa.
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Morphology of ray florets in chrysanthemums is tightly associated with cell division and cell expansion, both of which require proper cell cycle progression. Here we identified a Chrysanthemum lavandulifolium homolog ClCYCA2;1, whose expression in ray florets is negatively correlated with petal width in C. lavandulifolium. Two TCP transcription factors in CYCLOIDEA2 (CYC2) family, ClCYC2a interacts with and stabilizes ClCYC2b and the latter can bind to the promoter of ClCYCA2;1 to activate its transcription. Overexpression of ClCYCA2;1 in C. lavandulifolium reduces the size of capitula and ray florets. Cytological analysis reveals that ClCYCA2;1 overexpression inhibits both cell division and cell expansion via repressing mitotic cell cycle in ray florets whose latitudinal development was more negatively influenced leading to increased ratios of petal length to width at later developmental stages. Yeast two hybrid library screening reveals multiple ClCYCA2;1 interacting proteins including ARP7, and silencing ClARP7 inhibits the development of ray florets. Co-immunoprecipitation assays confirm that ClCYCA2;1 can induce the degradation of ClARP7 to inhibit the development of ray florets. Taken together, our study constitutes a regulatory network containing ClCYC2b-ClCYCA2;1-ClARP7 in ray floret development via governing mitosis, which may facilitate breeding efforts targeted for novel ornamental traits of chrysanthemums.
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Petal size is determined by cell division and cell expansion. Jasmonic acid (JA) has been reported to be associated with floral development, but its regulatory mechanism affecting petal size remains unclear. Here, we reveal the vital role of JA in regulating petal size and the duration of the cell division phase via the key JA signaling component RhMYC2. We show that RhMYC2 expression is induced by exogenous treatment with methyl jasmonate and decreases from stage 0 to stage 2 of flower organ development, corresponding to the cell division phase. Furthermore, silencing RhMYC2 shortened the duration of the cell division phase, ultimately accelerating flowering opening and resulting in smaller petals. In addition, we determined that RhMYC2 controls cytokinin homeostasis in rose petals by directly activating the expression of the cytokinin biosynthetic gene LONELY GUY3 (RhLOG3) and repressing that of the cytokinin catabolism gene CYTOKININ OXIDASE/DEHYDROGENASE6 (RhCKX6). Silencing RhLOG3 shortened the duration of the cell division period and produced smaller petals, similar to RhMYC2 silencing. Our results underscore the synergistic effects of JA and cytokinin in regulating floral development, especially for petal size in roses.
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The globally changing climatic condition is increasing the incidences of drought in several parts of the world. This is predicted and already shown to not only impact plant growth and flower development, but also plant-pollinator interactions and the pollination success of entomophilous plants. However, there is a large gap in our understanding of how drought affects the different flowers and pollen transfer among flowers in sexually polymorphic species. Here, we evaluated in monoecious Styrian oil pumpkin, and separately for female and male flowers, the responses of drought stress on flower production, petal size, nectar, floral scent and visitation by bumblebee pollinators. Drought stress adversely affected all floral traits studied, except floral scent. Although both flower sexes were adversely affected by drought stress, the effects were more severe on female flowers, with most of the female flowers even aborted before opening. The drought had negative effects on floral visitation by the pollinators, which generally preferred female flowers. Overall, our study highlights that the two flower sexes of a monoecious plant species are differently affected by drought stress and calls for further investigations to better understand the cues used by the pollinators to discriminate against male flowers and against flowers of drought-stressed plants.
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In Asia, Rosa spp. has been used in traditional medicine for the treatment of osteoarthritis, rheumatoid arthritis, and edema. In this study, we investigated the effect of rose petal extract (RPE) on high fat diet (HFD)-induced obesity in mice. C57BL/6J mice were fed with either an AIN-93G diet (normal control), a 60% HFD, or a HFD plus supplementation with RPE at 100 or 200 mg/kg body weight (HFD+R100, HFD+R200) for 14 weeks. The HFD increased the body weight gain, liver and fat weight, lipid profiles (total cholesterol, triglyceride, high density lipoprotein cholesterol, and low density lipoprotein cholesterol), and the serum aspartate aminotransferase and alanine aminotransferase levels of mice, while RPE supplementation significantly decreased these parameters compared with the HFD group. Furthermore, the HFD increased the protein expressions of adipogenesis- and lipogenesis-related factors and decreased the protein expression of lipolysis- and energy metabolism-related factors. Conversely, RPE supplementation significantly decreased the protein expression of adipogenesis- and lipogenesis-related factors and increased the protein expression of lipolysis- and energy metabolism-related factors compared to the HFD group. Taken together, the results provide preliminary evidence for the potential protective effects of the RPE against obesity.
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Manual segmentation of the petals of flower computed tomography (CT) images is time-consuming and labor-intensive because the flower has many petals. In this study, we aim to obtain a three-dimensional (3D) structure of Camellia japonica flowers and propose a petal segmentation method using computer vision techniques. Petal segmentation on the slice images fails by simply applying the segmentation methods because the shape of the petals in CT images differs from that of the objects targeted by the latest instance segmentation methods. To overcome these challenges, we crop two-dimensional (2D) long rectangles from each slice image and apply the segmentation method to segment the petals on the images. Thanks to cropping, it is easier to segment the shape of the petals in the cropped images using the segmentation methods. We can also use the latest segmentation method for the task because the number of images used for training is augmented by cropping. Subsequently, the results are integrated into 3D to obtain 3D segmentation volume data. The experimental results show that the proposed method can segment petals on slice images with higher accuracy than the method without cropping. The 3D segmentation results were also obtained and visualized successfully.
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The development of floral organs, crucial for the establishment of floral symmetry and morphology in higher plants, is regulated by MADS-box genes. In sunflower, the capitulum is comprised of ray and disc florets with various floral organs. In the sunflower long petal mutant (lpm), the abnormal disc (ray-like) floret possesses prolongated petals and degenerated stamens, resulting in a transformation from zygomorphic to actinomorphic symmetry. In this study, we investigated the effect of MADS-box genes on floral organs, particularly on petals, using WT and lpm plants as materials. Based on our RNA-seq data, 29 MADS-box candidate genes were identified, and their roles on floral organ development, especially in petals, were explored, by analyzing the expression levels in various tissues in WT and lpm plants through RNA-sequencing and qPCR. The results suggested that HaMADS3, HaMADS7, and HaMADS8 could regulate petal development in sunflower. High levels of HaMADS3 that relieved the inhibition of cell proliferation, together with low levels of HaMADS7 and HaMADS8, promoted petal prolongation and maintained the morphology of ray florets. In contrast, low levels of HaMADS3 and high levels of HaMADS7 and HaMADS8 repressed petal extension and maintained the morphology of disc florets. Their coordination may contribute to the differentiation of disc and ray florets in sunflower and maintain the balance between attracting pollinators and producing offspring. Meanwhile, Pearson correlation analysis between petal length and expression levels of MADS-box genes further indicated their involvement in petal prolongation. Additionally, the analysis of cis-acting elements indicated that these three MADS-box genes may regulate petal development and floral symmetry establishment by regulating the expression activity of HaCYC2c. Our findings can provide some new understanding of the molecular regulatory network of petal development and floral morphology formation, as well as the differentiation of disc and ray florets in sunflower.
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Flores , Regulación de la Expresión Génica de las Plantas , Helianthus , Proteínas de Dominio MADS , Proteínas de Plantas , Helianthus/genética , Helianthus/crecimiento & desarrollo , Helianthus/metabolismo , Flores/genética , Flores/crecimiento & desarrollo , Proteínas de Dominio MADS/genética , Proteínas de Dominio MADS/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
BACKGROUND: Rapeseed (Brassica napus L.) is one of the most important oil crops and a wildly cultivated horticultural crop. The petals of B. napus serve to protect the reproductive organs and attract pollinators and tourists. Understanding the genetic basis of petal morphology regulation is necessary for B. napus breeding. RESULTS: In the present study, the quantitative trait locus (QTL) analysis for six B. napus petal morphology parameters in a double haploid (DH) population was conducted across six microenvironments. A total of 243 QTLs and five QTL hotspots were observed, including 232 novel QTLs and three novel QTL hotspots. The spatiotemporal transcriptomic analysis of the diversiform petals was also conducted, which indicated that the expression of plant hormone metabolic and cytoskeletal binding protein genes was variant among diversiform petals. CONCLUSIONS: The integration of QTL and RNA-seq analysis revealed that plant hormones (including cytokinin, auxin, and gibberellin) and cytoskeleton were key regulators of the petal morphology. Subsequently, 61 high-confidence candidate genes of petal morphology regulation were identified, including Bn.SAUR10, Bn.ARF18, Bn.KIR1, Bn.NGA2, Bn.PRF1, and Bn.VLN4. The current study provided novel QTLs and candidate genes for further breeding B. napus varieties with diversiform petals.
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The absorption-dominated graphene porous materials, considered ideal for mitigating electromagnetic pollution, encounter challenges related to intricate structural design. Herein, petal-like graphene porous films with dendritic-like and honeycomb-like pores are prepared by controlling the phase inversion process. The theoretical simulation and experimental results show that PVP K30 modified on the graphene surface via van der Waals interactions promotes graphene to be uniformly enriched on the pore walls. Benefiting from the regulation of graphene distribution and the construction of honeycomb pore structure, when 15 wt % graphene is added, the porous film exhibits absorption-dominated electromagnetic shielding performance, compared with the absence of PVP K30 modification. The total electromagnetic shielding effectiveness is 24.1 dB, an increase of 170%; the electromagnetic reflection coefficient reduces to 2.82 dB; The thermal conductivity reaches 1.1 W/(m K), representing a 104% increase. In addition, the porous film exhibits improved mechanical properties, the tensile strength increases to 6.9 MPa, and the elongation at break increases by 131%. The method adopted in this paper to control the enrichment of graphene in the pore walls during the preparation of honeycomb porous films by the phase inversion method can avoid the agglomeration of graphene and improve the overall performance of the porous graphene porous films.
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Jasmonates are growth regulators that play a key role in flower development, fruit ripening, root growth, and plant defence. The study explores the coordination of floral organ maturation to ensure proper flower opening for pollination and fertilization. A new mutant (jar1b) was discovered, lacking petal elongation and flower opening but showing normal pistil and stamen development, leading to parthenocarpic fruit development. The mutation also enhanced the elongation of roots while reducing the formation of root hairs. BSA sequencing showed that jar1b is a missense mutation in the gene CpJAR1B, which encodes the enzyme that catalyzes the conjugation between JA and the amino acid isoleucine. The loss of function mutation in CpJAR1B produced a deficiency in biologically active (+) -7-iso-jasmonoyl-L-isoleucine (JA-Ile), which was not complemented by the paralogous gene CpJAR1A or any other redundant gene. Exogenous application of methyl jasmonate (MeJA) demonstrated that jar1b is partially insensitive to JA in both flowers and roots. Further experimentation involving the combination of JA-Ile deficient and ethylene-deficient, and ET insensitive mutations in double mutants revealed that CpJAR1B mediated ET action in female petal maturation and flower opening, but JA and ET have independent additive effects as negative regulators of the set and development of squash fruits. CpJAR1B also regulated the aperture of male flowers in an ethylene-independent manner. The root phenotype of jar1b and effects of external MeJA treatments indicated that CpJAR1B has a dual role in root development, inhibiting the elongation of primary and secondary roots, but promoting the formation of root hairs.
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Cucurbita , Ciclopentanos , Flores , Frutas , Oxilipinas , Proteínas de Plantas , Ciclopentanos/farmacología , Ciclopentanos/metabolismo , Oxilipinas/farmacología , Oxilipinas/metabolismo , Flores/genética , Flores/crecimiento & desarrollo , Flores/efectos de los fármacos , Cucurbita/genética , Cucurbita/crecimiento & desarrollo , Frutas/genética , Frutas/crecimiento & desarrollo , Frutas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Isoleucina/farmacología , Isoleucina/metabolismo , Isoleucina/análogos & derivados , Mutación , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Acetatos/farmacología , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/efectos de los fármacos , Reguladores del Crecimiento de las Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/farmacologíaRESUMEN
Petal abscission affects the growth, development, and economic value of plants, but the mechanism of ethylene-ROS-induced petal abscission is not clear. Therefore, we treated roses with different treatments (MOCK, ETH, STS, and ETH + STS), and phenotypic characteristics of petal abscission, changed ratio of fresh weight, morphology of cells in AZ and the expression of RhSUC2 were analyzed. On this basis, we measured reactive oxygen species (ROS) content in petals and AZ cells of roses, and analyzed the expression levels of some genes related to ROS production and ROS scavenging. Ethylene promoted the petal abscission of rose through decreasing the fresh weight of the flower, promoting the stacking and stratification of AZ cells, and repressing the expression of RhSUC2. During this process, ethylene induced the ROS accumulation of AZ cells and petals mainly through increasing the expressions of some genes (RhRHS17, RhIDH1, RhIDH-III, RhERS, RhPBL32, RhFRS5, RhRAC5, RhRBOHD, RhRBOHC, and RhPLATZ9) related to ROS production and repressing those genes (RhCCR4, RhUBC30, RhSOD1, RhAPX6.1, and RhCATA) related to ROS scavenging. In summary, ROS and related regulatory factors involved in ethylene induced petal abscission in roses.
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The flower perianth has various, non-mutually exclusive functions, such as visual signalling to pollinators and protecting the reproductive organs from the elements and from florivores, but how different perianth structures and their different sides play a role in these functions is unclear. Intriguingly, in many species there is a clear colour difference between the different sides of the perianth, with colour patterns or pigmentation present on only one side. Any adaptive benefit from such colour asymmetry is unclear, as is how the asymmetry evolved. In this viewpoint paper, we address the phenomenon of flowers with differently coloured inner and outer perianth sides, focusing on petals of erect flowers. Guided by existing literature and our own observations, we delineate three non-mutually exclusive evolutionary hypotheses that may explain the factors underlying differently coloured perianth sides. The pollen-protection hypothesis predicts that the outer side of petals contributes to protect pollen against UV radiation, especially during the bud stage. The herbivore-avoidance hypothesis predicts that the outer side of petals reduces the flower's visibility to herbivores. The signalling-to-pollinators hypothesis predicts that flower colours evolve to increase conspicuousness to pollinators. The pollen-protection hypothesis, the herbivore-avoidance hypothesis, and the signalling-to-pollinators hypothesis generate largely but not entirely overlapping predictions about the colour of the inner and outer side of the petals. Field and laboratory research is necessary to disentangle the main drivers and adaptive significance of inner-outer petal side colour asymmetry.