Yellow Petals Research Articles

<p><strong>First record of<em> Turnera ulmifolia</em> L. (Turneraceae) as introduced in Brazil</strong></p>

The first record of Turnera ulmifolia (Turneraceae) for Brazil is presented here. The species occurs mainly in SE Mexico, Central America and Caribbean islands, with only one record from South America. It can be recognized by ovoid and foliaceous prophylls, with serrate margins and laciniate appendages and/or extrafloral nectaries, showy flowers with yellow petals, without basal spot. Taxonomic comments, a distribution map and photographs of the species are provided.

<p><strong>Not extinct after all: rediscovery of <em>Commelina dielsii</em> (Commelinaceae) after 140 years, and first record of this species in Uruguay</strong></p>

Commelina dielsii is a species notable for being, together with the southern Brazilian C. catharinensis, the only native Commelina from the Americas with yellow petals. The species was up until now only known from the type gathering, made in 1878 in Entre Ríos province, north-eastern Argentina. Because it had not been collected since then, the species was considered as likely extinct. We present here the rediscovery of this species after 140 years, as the species was recently found in western Uruguay, in pampean environment. This also corresponds to the first record of the species in Uruguay. We also present field photographs, a morphological description, a distribution map for the species and its conservation status assessment.

Taxonomic novelties within a non‐monophyletic lineage: a new Mexican species of Desmopsis (Annonaceae)

A new species of Annonaceae endemic to Mexico is described and illustrated. Desmopsis dubia sp. nov. is placed within the Desmopsis–Stenanona clade and is clearly different from all other species of Neotropical Miliuseae by the combination of lower surface of leaves pubescent; tertiary venation strongly percurrent; leafy bracts absent at the base of the pedicels; sepals connate at the base and persistent in fruit; petals fleshy and stiff, elliptic to ovate with food bodies at the base of the inner ones; and cylindrical monocarps with ligneous exocarp. We discuss its phylogenetic relationships and placement within the genus Desmopsis and a key to the Mexican species of Desmopsis and Stenanona with yellow or greenish petals is provided.

When three become two: Drosera coalara links Drosera citrina with Drosera nivea

The pygmy sundews (Drosera section Bryastrum) are the second-largest group of Australian Drosera in terms of species number following the tuberous sundews. According to the latest revisions (Fleischmann et al. 2018; Robinson et al. 2018) they currently comprise 51 species in southwest Western Australia and six named natural hybrids (Lowrie 2014; Lowrie et al. 2017). Within the pygmy Drosera, a wide range of flower colors can be found, ranging from pure white, various shades of pink, metallic orange, and red to yellow colors, quite often with bi- or rarely even tricolored petals (Lowrie 1989; Robinson et al. 2018). The color combination of lime yellow petals with white base has thus far been considered to be unique to D. citrina (Lowrie & Carlquist 1992; Lowrie 2014; Lowrie et al. 2017).

Towards breeding of rapeseed (Brassica napus) with alien cytoplasm and powdery mildew resistance from Ethiopian mustard (Brassica carinata).

Powdery mildew (PM), caused by Erysiphe cruciferarum, is an epidemic of oil rapeseed (Brassica napus L.) growing worldwide, but PM resistant germplasm is rare in this species. We screened 102 accessions of B. napus and other cruciferous species and found an Ethiopian mustard (Brassica carinata) cultivar ‘White flower’ immune to PM in both the field and greenhouse. Outcrossing in the female parent ‘White flower’ was promoted by using a chemical gametocide tribenuron-methyl, to obtain hybrid seeds of distant hybridization with an elite B. napus cultivar ‘Zhongshuang11’. Three true F1 hybrids with B. carinata cytoplasm were obtained without using embryo rescue, which showed complete male sterility and light yellow petals. The hybrid plants and the progenies derived from backcrossing were validated using morphological traits, seed quality, and molecular markers. Five lines in the BC1F3 generation, named ‘W7-1’, ‘W7-4’, ‘W7-6’, ‘W8-1’, and ‘W8-3’, and one BC2F2 line ‘W3PS-1’, whose young leaf was yellow green, were identified to be resistant or moderately resistant to PM. The seed quality and some morphological traits of these lines resembled the parent ‘Zhongshuang11’, indicating that the resistance gene(s) has been preliminarily introduced into B. napus.

Spray Chrysanthemum ‘Field Green’ with Yellow Green Petal, Single Type, and White Rust Resistance for Cut Flower

The chrysanthemum cultivar Field Green (Chrysanthemum x morifolium) was developed at the National Institute of Horticultural and Herbal Science, Rural Development Administration (RDA) in 2012. The cultivar Field Green was derived from the artificial crossing in 2008 between two spray chrysanthemum cultivars, Laque Roicks, a maternal p arent with y ellow single t ype flower, and F rill Green, a paternal parent with a green single type and white rust disease resistance. The vigorous plants with green petals and stable flower shapes were selected in 2009. After an evaluation of the characteristics, including shading culture in summer and retarding culture in spring and consecutive selections from 2010 to 2012, the final selection was made. The flowering time of Field Green was October 26 in a natural day length, and year-round production was possible by day-length treatment. This cultivar has single-type flowers with bright green ray florets and green disc florets. The number of ray florets is 18.8, and the flower diameter is 7.1 cm. The growth of the plant is vigorous, with a plant height of 130 cm. Field Green is highly resistant to white rust disease, and vase life is about 20 days in autumn. Number 2013-153 was applied to Field Green on February 20, 2013 for variety protection; its plant variety protection rights were then registered (No. 4839) on April 2, 2014 at the Korea Seed and Variety Service.

Expression of CCD4 gene involved in carotenoid degradation in yellow-flowered Petunia × hybrida

Petunia is a popular commercial bedding plant that comes in many colors, but there are no petunia cultivars with deep yellow petals. The carotenoid degradation gene carotenoid cleavage dioxygenase (CCD4) was isolated from white and yellow-flowered petunia and we found the 226-bp insertion of a non-autonomous transposable element tourist-like miniature-inverted repeat (MITE) in the coding region of CCD4 only in yellow cultivars. The insertion interrupts gene expression because of a premature stop codon after the TE insertion and could form secondary structures in hairpin RNA that could then be processed into a mature miRNA. Here, the normal function of CCD4 isolated from a white cultivar was introduced to a yellow cultivar. The transformants showed more fading pale-yellow flowers and carotenoid content was decreased. These results indicate that transformed CCD4 expression promoted carotenoid degradation and the lack of CCD4 expression results in more carotenoid accumulation in wild-type yellow-flowered petunia.

<p><strong>A new species of <em>Phragmipedium</em> (Orchidaceae: Cypripedioideae) from Peru</strong></p>

A new species of Phragmipedium section Lorifolia, P. cabrejosii, is described and illustrated from Peru, and its affinities are discussed. It is mainly compared with P. caricinum, from which it is distinguished by the simple inflorescence, the elliptic dorsal sepal, that is apically white, the shorter, apically twisted pale yellow petals tinged with rose, and the ovate-subrhombic staminodial shield (vs. reniform).

(2720) Proposal to conserve the name Grewia rhamnifolia (Malvaceae: Grewioideae) with a conserved type

(2720) Proposal to conserve the name <i>Grewia rhamnifolia</i> (<i>Malvaceae</i>: <i>Grewioideae</i>) with a conserved type

Identification and Characterization of Major Constituents in Different-Colored Rapeseed Petals by UPLC–HESI-MS/MS

Oilseed rape (Brassica napus L.) is the second highest yielding oil crop worldwide. In addition to being used as an edible oil and a feed for livestock, rapeseed has high ornamental value. In this study, we identified and characterized the main floral major constituents, including phenolic acids and flavonoids components, in rapeseed accessions with different-colored petals. A total of 144 constituents were identified using ultrahigh-performance liquid chromatography-HESI-mass spectrometry (UPLC-HESI-MS/MS), 57 of which were confirmed and quantified using known standards and mainly contained phenolic acids, flavonoids, and glucosinolates compounds. Most of the epicatechin, quercetin, and isorhamnetin derivates were found in red and pink petals of B. napus, while kaempferol derivates were in yellow and pale white petals. Moreover, petal-specific compounds, including a putative hydroxycinnamic acid derivative, sinapoyl malate, 1-O-sinapoyl-β-d-glucose, feruloyl glucose, naringenin-7-O-glucoside, cyanidin-3-glucoside, cyanidin-3,5-di-O-glucoside, petunidin-3-O-β-glucopyranoside, isorhamnetin-3-O-glucoside, kaempferol-3-O-glucoside-7-O-glucoside, quercetin-3,4'-O-di-β-glucopyranoside, quercetin-3-O-glucoside, and delphinidin-3-O-glucoside, might contribute to a variety of petal colors in B. napus. In addition, bound phenolics were tentatively identified and contained three abundant compounds (p-coumaric acid, ferulic acid, and 8-O-4'-diferulic acid). These results provide insight into the molecular mechanisms underlying petal color and suggest strategies for breeding rapeseed with a specific petal color in the future.

The MYB Activator WHITE PETAL1 Associates with MtTT8 and MtWD40-1 to Regulate Carotenoid-Derived Flower Pigmentation in Medicago truncatula.

Carotenoids are a group of natural tetraterpenoid pigments with indispensable roles in the plant life cycle and the human diet. Although the carotenoid biosynthetic pathway has been well characterized, the regulatory mechanisms that control carotenoid metabolism, especially in floral organs, remain poorly understood. In this study, we identified an anthocyanin-related R2R3-MYB protein, WHITE PETAL1 (WP1), that plays a critical role in regulating floral carotenoid pigmentation in Medicago truncatula Carotenoid analyses showed that the yellow petals of the wild-type M. truncatula contained high concentrations of carotenoids that largely consisted of esterified lutein and that disruption of WP1 function via Tnt1 insertion led to substantially reduced lutein accumulation. WP1 mainly functions as a transcriptional activator and directly regulates the expression of carotenoid biosynthetic genes including MtLYCe and MtLYCb through its C-terminal acidic activation motif. Further molecular and genetic analyses revealed that WP1 physically interacts with MtTT8 and MtWD40-1 proteins and that this interaction facilitates WP1's function in the transcriptional activation of both carotenoid and anthocyanin biosynthetic genes. Our findings demonstrate the molecular mechanism of WP1-mediated regulation of floral carotenoid pigmentation and suggest that the conserved MYB-basic-helix-loop-helix-WD40 regulatory module functions in carotenoid biosynthesis in M. truncatula, with specificity imposed by the MYB partner.

Insertion of a CACTA-like transposable element disrupts the function of the BoCCD4 gene in yellow-petal Chinese kale

Brassica oleracea comprises several important subspecies, including cabbage, broccoli, cauliflower, Chinese kale, and kohlrabi. The petal color of Chinese kale is mostly white and sometimes yellow. To explore the genetic basis of petal color variation in Chinese kale, F2 and BC1 (backcross) populations were constructed from the cross of two inbred lines, 2114 (yellow petal) and 2116 (white petal). Genetic analysis of the F2 and BC1 populations demonstrated that yellow petal color was controlled by a single recessive nuclear gene, termed cpc-2. Insertion-deletion (InDel) markers, designed based on the parental resequencing data, were used to map cpc-2. The fine mapping results indicated that the cpc-2 gene was located in a 569-kb interval on chromosome C03 flanked by InDel markers ZB636 and ZB692, with genetic distances of 0.3 cM and 0.6 cM, respectively. By analyzing the nucleotide variations and annotations of the genes in this interval, a CCD4 family gene was predicted to be a candidate for cpc-2 and renamed BoCCD4.2. In addition, insertion of the CACTA-like transposable element (TE3) interrupted the function of the BoCCD4 gene, which may have resulted in the loss of function of BoCCD4 and the petal color transition from white to yellow. The TE3 insertion in the BoCCD4 gene was also present in 63 cabbage inbred lines among 159 accessions, which revealed that the TE3-type null allele of BoCCD4 formed before the divergence of the two subspecies cabbage and Chinese kale and that Chinese kale evolved much earlier than cabbage. This study lays the foundation for cloning BoCCD4.2 and revealing the molecular mechanism underlying petal color formation in Chinese kale.

Primary Screening of Antioxidant Activity, Total Polyphenol Content, Carotenoid Content, and Nutritional Composition of 13 Edible Flowers from Japan.

Thirteen edible flowers, which are used as food ingredients in Japan, were evaluated as possible sources of antioxidants and biological compounds. The nutritional composition, total polyphenol content (TPC), carotenoid content, and antioxidant activity of the edible flowers were determined based on the oxygen radical absorbance capacity (ORAC). Water was the main constituent of edible flowers, and carbohydrates were the primary macronutrients. The TPC of the edible flowers varied from 1.47 to 13.08 mg gallic acid equivalent/g fresh weight (FW). Carotenoids, including β-carotene and β-cryptoxanthin, were detected mainly in the edible flowers with petal colors ranging from yellow to orange, but especially in primula and cosmos yellow flowers, which have yellow petals. The ORAC value of the hydrophilic extract (HORAC) of edible flowers was higher than the ORAC value of the lipophilic extract (LORAC). The total antioxidant capacity (TAC) ranged from 33.03 to 320.36 μM Trolox equivalent/g FW. The highest TPC and TAC were observed in cosmos yellow flowers. On the basis of Pearson’s correlation coefficient, the HORAC value and the TPC of the analyzed edible flowers were highly correlated (r=0.736). This preliminary study indicates that edible flowers are a potential source of antioxidants, and the addition of edible flowers to the human diet may be associated with health benefits.

A Spray Chrysanthemum Cultivar for Cut Flower, ‘Perky Star’ , with Excellent Growth and Flowering Characteristics at High Temperature Period

A new spray chrysanthemum (Dendranthema grandiflorum) cultivar ‘Perky Star’ was developed at Gyeonggi-do Agricultural Research and Extension Services, Korea, in 2016. Cultivar ‘Sei-Vista’, which has dark yellow colored flower and narrow and long ray floret, was crossed with ‘Amisa’, which has good flower shape, in 2012. This attempt was conducted to breed well-growing varieties at high temperatures period. The growth and flowering characteristics of the lines were investigated in retarding, shading and natural condition from 2014 to 2016, and a preference investigation was carried out in 2016, resulting in the GCS12-81-150 line being finally selected and named ‘Perky Star’. An application was made for a plant variety protection right for ‘Perky Star’ in 2017 (No. 2017-64), which was granted in 2018 (Korea Seed & Variety Service No. 7165). ‘Perky Star’ has single type flowers with yellow petals. This cultivar is suitable for export in summer season because it has good expression of the flower color and grows well at high temperatures and its petals are thick. In the autumn, spring, and summer cultures, the numbers of days to flowering under short day treatments were 49, 49 and 53 days, the plant heights were 88.3 cm, 84.2 cm, and 103.3 cm, the flower diameters were 5.1 cm, 4.8 cm, and 4.8 cm, and the numbers of flowers per stem were 25.0, 21.5, and 38.8, respectively. The cultivar ‘Perky Star’ was not fully resistant to white rust, showed the vase life of 21.3 days in autumn and got the preference degree of 4.2 in 5 points.

Fine mapping and candidate gene analysis of the yellow petal gene ckpc in Chinese kale (Brassica oleracea L. var. alboglabra Bailey) by whole-genome resequencing

Chinese kale is a characteristic vegetable crop originating from China and being suggested to be a possible ancestor of various cultivated B. oleracea vegetables. It has both white and yellow petals and is therefore a desirable plant for use in research on petal color formation. In our study, the Chinese kale landrace YCK-1 (yellow petals) was crossed with the Chinese kale inbred line Lb07M (white petals) to construct mapping populations for genetic analysis and fine mapping of the petal color gene. The results indicated that yellow petal color is controlled by a single recessive gene named ckpc, which was preliminarily located in a 2.06-Mb candidate region of chromosome C03 using whole-genome resequencing combined with bulked segregant analysis (BSA). Fine mapping with traditional molecular marker technology was used to narrow down the ckpc gene in a 69.0-kb interval flanked by the markers M916 and SNP4 at genetic distances of 0.07 cM and 0.04 cM, respectively. Gene annotation revealed 5 genes in that region, and Bo3g158650 was annotated as a carotenoid cleavage dioxygenase 4 (CCD4) gene, which is known to function in flower and flesh color formation. Sequence analysis revealed that the Bo3g158650 gene in the white-petaled parent, Lb07M, had an identical sequence to that in the ‘TO1000’ reference genome, while a 7.61-kb CACTA-like transposable element 1 (TE1) insertion was found in this gene in the yellow-petaled parent, YCK-1. These results increase the understanding of the mechanism underlying petal color formation in Brassica.

Differences in flavonoid pathway metabolites and transcripts affect yellow petal colouration in the aquatic plant Nelumbo nucifera

BackgroundThe Asia lotus (Nelumbo nucifera Gaertn.) is an ornamental aquatic plant with high economic value. Flower colour is an important ornamental trait, with much of N. nucifera breeding focusing on its yellow flowers. To explore the yellow flower colouration mechanism in N. nucifera, we analysed its pigment constituents and content, as well as gene expression in the flavonoid pathway, in two N. nucifera cultivars.ResultsWe performed metabolomic and gene expression analyses in two N. nucifera cultivars with yellow and white flowers, Molinqiuse (MLQS) and Yeguangbei (YGB), respectively, at five stages of flower colouration. Based on phenotypic observation and metabolite analyses, the later stages of flower colouration (S3–S5) were determined to be key periods for differences between MLQS and YGB, with dihydroflavonols and flavonols differing significantly between cultivars. Dihydroquercetin, dihydrokaempferol, and isorhamnetin were significantly higher in MLQS than in YGB, whereas kaempferol was significantly higher in YGB. Most of the key homologous structural genes in the flavonoid pathway were significantly more active in MLQS than in YGB at stages S1–S4.ConclusionIn this study, we performed the first analyses of primary and secondary N. nucifera metabolites during flower colouration, and found that isorhamnetin and kaempferol shunting resulted in petal colour differences between MLQS and YGB. Based on our data integration analyses of key enzyme expression in the putative flavonoid pathways of the two N. nucifera cultivars, NnFLS gene substrate specificity and differential expression of NnOMTs may be related to petal colour differences between MLQS and YGB. These results will contribute to determining the mechanism of yellow flower colouration in N. nucifera, and will improve yellow petal colour breeding in lotus species.

An outstanding new species of Senna (Fabaceae: Caesalpinioideae) from southern Puebla, Mexico

Senna acatlanensis is described and illustrated here. This species is restricted to a forest ecotone in southern Puebla (Mexico), and stands out by its unique large asymmetric flowers, with yellow petals that do not fade away to reddish-brown as they dry-out, heteromorphic and variable androecium; with four staminodes, ten or less fertile stamens; by its pendulous, cylindrical fruits, with chartaceous strigillose valves, and inter-seminal septa with a black-pulpy endocarp that surrounds exareolate seeds. These morphological attributes in addition to leaves with two pairs of leaflets, anthers with beaks, gynoecium multi-ovulated, and transversely oriented seed, turned broadside to the septa placed this new species within the series Bacillares. Illustrations, taxonomic comments, distribution and conservation status are provided with a key to the Mexican species of series Bacillares.

Generation of Yellow Flowers of the Japanese Morning Glory by Engineering Its Flavonoid Biosynthetic Pathway toward Aurones.

Wild-type plants of the Japanese morning glory (Ipomoea nil) produce blue flowers that accumulate anthocyanin pigments, whereas its mutant cultivars show wide range flower color such as red, magenta and white. However, I. nil lacks yellow color varieties even though yellow flowers were curiously described in words and woodblocks printed in the 19th century. Such yellow flowers have been regarded as 'phantom morning glories', and their production has not been achieved despite efforts by breeders of I. nil. The chalcone isomerase (CHI) mutants (including line 54Y) bloom very pale yellow or cream-colored flowers conferred by the accumulation of 2', 4', 6', 4-tetrahydoroxychalcone (THC) 2'-O-glucoside. To produce yellow phantom morning glories, we introduced two snapdragon (Antirrhinum majus) genes to the 54Y line by encoding aureusidin synthase (AmAS1) and chalcone 4'-O-glucosyltransferase (Am4'CGT), which are necessary for the accumulation of aureusidin 6-O-glucoside and yellow coloration in A. majus. The transgenic plants expressing both genes exhibit yellow flowers, a character sought for many years. The flower petals of the transgenic plants contained aureusidin 6-O-glucoside, as well as a reduced amount of THC 2'-O-glucoside. In addition, we identified a novel aurone compound, aureusidin 6-O-(6″-O-malonyl)-glucoside, in the yellow petals. A combination of the coexpression of AmAS1 and Am4'CGT and suppression of CHI is an effective strategy for generating yellow varieties in horticultural plants.

Chemical composition of floral scents from three Plumeria rubra L. (Apocynaceae) forms linked to petal color proprieties

The floral scents of three forms of cultivated Plumeria rubra L. were evaluated through mass flowering phenology using the dynamic headspace adsorption method and were identified with coupled gas chromatography and mass spectrometry. The forms P. rubra f. acutifolia and P. rubra f. lutea had white and yellow flower petals, respectively, and the flower petals of P. rubra f. rubra were red. Although 68 components of the flower scents of the three forms were recorded in different proportions, only 14 chemical compounds were identified with statistically significance. The main volatile compounds in the red form of P. rubra L. were fatty acid derivatives (56.75%). The main compounds in the white and yellow forms of P. rubra L. were benzenoid and terpene, with proportions of 48.38% and 33.33% in P. rubra f. acutifolia and proportions of 42.30% and 47.43% in P. rubra f. lutea, respectively. These differences in the flower scents might be one result of the minor genetic differences between these forms, similar to the role of genetic differences in the flower color combinations of the three forms. We conclude that petal color traits can, to some extent, reflect differences in floral scent compositions and that minor genetic differences of different plant forms exert impacts not only on flower color but also on the phytochemistry of floral scents.

Natural Variation in Flower Color and Scent in Populations of Eruca sativa (Brassicaceae) Affects Pollination Behavior of Honey Bees.

Plants of Eruca sativa Mill. (Brassicaceae) from desert and Mediterranean populations in Israel differ in flower color and size. In the desert habitat, the population has higher abundance of flowers with cream color and longer petals, whereas in the Mediterranean habitat, the population has higher abundance of flowers with yellow and shorter petals. Choice experiments with honey bee foragers (Apis mellifera Linn., Apidae, Hymenoptera), the main pollinator in the natural habitat in Israel, confirmed that they are more attracted to the yellow flower morph than to the cream one. A proboscis extension response test indicated that honey bees are able to discriminate between flower scents of the desert and Mediterranean populations. Considering the advantage of plants of the yellow morph in attracting pollinators, we further tested in a common garden experiment whether these possess higher fitness than plants of the desert population. Indeed, a significant association was found between flower color and fruit set, and seed mass. In general, our results provide evidence for ecotypic differentiation between populations imposed by pollinators. The advantage of the yellow color morph in attracting pollinators may explain its dominance among plants of the Mediterranean population. We discuss why the cream color morph may be dominant in the desert habitat, considering the possibility of different pollinators, tradeoffs between traits, or pleiotropy.