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There are significant societal repercussions from our excessive use of plastic products derived from petroleum. In response to the increasing environmental implications of plastic wastes, biodegradable materials have been proven to be an effective means of mitigating environmental issues. Therefore, protein- and polysaccharide-based polymers have gained widespread attention recently. In our study, for increasing the strength of a biopolymer (Starch), we used ZnO dispersed nanoparticles (NPs), which resulted in the enhancement of other functional properties of the polymer. The synthesized NPs were characterized using SEM, XRD, and Zeta potential values. The preparation techniques are completely green, with no hazardous chemicals employed. The floral extract employed in this study is Torenia fournieri (TFE), which is prepared using a mixture of ethanol and water and possesses diverse bioactive features and pH-sensitive characteristics. The prepared films were characterized using SEM, XRD, FTIR, contact angle and TGA. The incorporation of TFE and ZnO (SEZ) NPs was found to increase the overall nature of the control film. The results obtained from this study confirmed that the developed material is suitable for wound healing and can also be used as a smart packaging material.

The quality of light has played an important role not only in the vegetative growth, but also in the reproductive stage of the plant. Normally, the endogenous transformation has hardly been observed under the general condition. This study analyzed the endogenous changes, which were particularly influenced by the spectrum of light emitting diode (LED) with induction flowering time from 30th to 40th day. In the 40th day of the flowering process, when the average number of flower buds get the highest, endogenous carbohydrate content was decreased. However, in this phase, plants need more energy; therefore, the net photosynthetic rate tends to increase in order to supply energy for flowering. Throughout 40 days of culture, the net photosynthetic rate had an increase in the concentration of CO2. In particular, it reached the peak when being induced under the light combination ratio 7:3 of red and blue light (0.222 µmol mol-1 h-1). The sugar content also followed the same trajectory; however, it dropped at the end of the period. Among all the experiments, the ratio of red and blue light 5:5 resulted in the highest content of endogenous carbohydrate source (722.30 µg g-1). Moreover, the morphological anatomy of shoot apical meristem in flowering stage was also studied. The floral transition at meristem and floral architecture is as similar as that of Arabidopsis. A typical flower of T. fournieri also consists of a sequence: sepals – petals – stamens – carpels. The SAM is organized into three different zones such as the central zone (CZ), the peripheral zone (PZ) surrounding the CZ and the rib zone (RZ) underneath the CZ.

Torenia fournieriis an important ornamental plant in Bangladesh that can grow in a variety of soils in moist areas. It is an extensively studied plant species to investigate fertilization and movement of chromosome. This investigation was carried out to establish a suitable protocol for large scalein vitroregeneration.In vitromass propagation is one of the best biotechnological methods that can be ensured rapid multiplication of disease-free propagules and genetically identical plant production for plant breeding.In vitroplant regeneration inToreniawas obtained on MS medium supplemented with 2.0 mg/l BA using nodal segments as explants. Maximum 95% of the explants were produced multiple shoots in this medium. The maximum number (12) of shoot per explant and the maximum shoot length of 5.5 cm were observed after 60 days of culture. The well-rooted were found when strong and healthy shoots were transferred into half strength of MS+ 1.0 mg/l IBA. The maximum number (18) of root per shoot and the maximum root length of 4.83 cm were recorded in this medium after 30 days of culture whilst 90% of shoots induced root.In vitroraised plantlets did not show any morphological variation and 90% of plantlets was survived in the natural environment. In this study, rapid multiplication of planting material inToreniathroughin vitropropagation techniques such as shoot initiation, multiplication, rooting, hardening and optimizing the concentrations and combinations of plant growth regulators is developed. This regeneration protocol will be helpful inin vitromutagenesis technique to create new variation of this plant within short time cycle.

Torenia fournieri belongs to the genus Torenia in the family Linderniaceae. The complete chloroplast genome of T. fournieri was sequenced and analyzed by Illumina sequencing in this study. The full length of the complete chloroplast genome is 153,938 bp, containing a pair of inverted repeat regions of 24,805 bp (IRa and IRb) separated by a large single copy region (LSC) of 85,498 bp and a small single copy region (SSC) of 18,830 bp. The T. fournieri chloroplast genome encodes 131 genes, comprising 87 protein-coding genes, 36 tRNA genes, 8 rRNA genes, without pseudogene. Phylogenetic analysis showed that T. fournieri was closely related to T. benthamiana and T. concolor within the genus Torenia in family Linderniaceae.

Background The wishbone flower or Torenia fournieri Lind., an annual from tropical Indochina and southern China, is a popular ornamental plant, and many interspecific (T. fournieri × T. concolor) hybrid lines have been bred for the international market. The cultivated lines show a pattern of genetic similarity that correlates with floral color which informs on future breeding strategies. This study aimed to perform genetic analysis and population structure of cultivated hybrid lines comparing with closely related T. concolor wild populations. Methods We applied the retrotransposon based iPBS marker system for genotyping of a total of 136 accessions from 17 lines/populations of Torenia. These included 15 cultivated lines of three series: Duchess (A, B, C); Kauai (D, E, F, G, H, I, J); Little Kiss (K, L, M, N, P) and two wild T. concolor populations (Q and R). PCR products from each individual were applied to estimate the genetic diversity and differentiation between lines/populations. Results Genotyping results showed a pattern of genetic variation differentiating the 17 lines/populations characterized by their specific floral colors. The final PCoA analysis, phylogenetic tree construction, and Bayesian population structural bar plot all showed a clear subdivision of lines/populations analysed. The 15 cultivated hybrid lines and the wild population Q that collected from a small area showed the lowest genetic variability while the other wild population R which sampled from a larger area had the highest genetic variability. Discussion The extremely low genetic variability of 15 cultivated lines indicated that individual line has similar reduction in diversity/heterozygosity from a bottleneck event, and each retained a similar (but different from each other) content of the wild genetic diversity. The genetic variance for the two wild T. concolor populations could be due to our varied sampling methods. The two wild populations (Q, R) and the cultivated hybrid lines (I, K, M, N, P) are genetically more closely related, but strong positive correlations presented in cultivated lines A, C, E, M, and N. These results could be used to guide future Torenia breeding. Conclusions The genetic variation and population structure found in our study showed that cultivated hybrid lines had similar reduction in diversity/heterozygosity from a bottleneck event and each line retained a similar (but different from each other) content of the wild genetic diversity, especially when strong phenotypic selection of floral color overlaps. Generally, environmental factors could induce transposon activation and generate genetic variability which enabled the acceleration of the evolutionary process of wild Torenia species. Our study revealed that wild Torenia populations sampled from broad geographic region represent stronger species strength with outstanding genetic diversity, but selective breeding targeting a specific floral color decreased such genetic variability.

Shoot regeneration involves reprogramming of somatic cells and de novo organization of shoot apical meristems (SAMs). In the best-studied model system of shoot regeneration using Arabidopsis, regeneration is mediated by the auxin-responsive pluripotent callus formation from pericycle or pericycle-like tissues according to the lateral root development pathway. In contrast, shoot regeneration can be induced directly from fully differentiated epidermal cells of stem explants of Torenia fournieri (Torenia), without intervening the callus mass formation in culture with cytokinin; yet, its molecular mechanisms remain unaddressed. Here, we characterized this direct shoot regeneration by cytological observation and transcriptome analyses. The results showed that the gene expression profile rapidly changes upon culture to acquire a mixed signature of multiple organs/tissues, possibly associated with epidermal reprogramming. Comparison of transcriptomes between three different callus-inducing cultures (callus induction by auxin, callus induction by wounding and protoplast culture) of Arabidopsis and the Torenia stem culture identified genes upregulated in all the four culture systems as candidates of common factors of cell reprogramming. These initial changes proceeded independently of cytokinin, followed by cytokinin-dependent, transcriptional activations of nucleolar development and cell cycle. Later, SAM regulatory genes became highly expressed, leading to SAM organization in the foci of proliferating cells in the epidermal layer. Our findings revealed three distinct phases with different transcriptomic and regulatory features during direct shoot regeneration from the epidermis in Torenia, which provides a basis for further investigation of shoot regeneration in this unique culture system.

The progression of the cell cycle is continuous in most cells, but gametes (sperm and egg cells) exhibit an arrest of the cell cycle to await fertilization to form a zygote, which then continues through the subsequent phases to complete cell division. The phase in which gametes of flowering plants arrest has been a matter of debate, since different phases have been reported for the gametes of different species. In this study, we reassessed the phase of cell-cycle arrest in the gametes of two species, Arabidopsis (Arabidopsis thaliana) and Torenia fournieri. We first showed that 4’, 6-diamidino-2-phenylindole staining was not feasible to detect changes in gametic nuclear DNA in T. fournieri. Next, using 5-ethynyl-2’-deoxyuridine (EdU) staining that detects DNA replication by labeling the EdU absorbed by deoxyribonucleic acid, we found that the replication of nuclear DNA did not occur during gamete development but during zygote development, revealing that the gametes of these species have a haploid nuclear DNA content before fertilization. We thus propose that gametes in the G1 phase participate in the fertilization event in Arabidopsis and T. fournieri.

Made available in DSpace on 2019-10-06T15:25:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01. Added 1 bitstream(s) on 2019-10-09T18:34:46Z : No. of bitstreams: 1 S2447-536X2018000300261.pdf: 1244219 bytes, checksum: d750c431c56a91bdd7de5e9a2ebd91d9 (MD5) De maneira geral, os telhados verdes extensivos são definidos como toda cobertura revestida de vegetação herbácea e substrato superficial, entretanto, no Brasil são poucas as informações referentes aos materiais para instalação e manutenção desses sistemas, sendo essencial a busca de melhores espécies e substratos adaptados as condições tropicais. Assim, objetivou-se avaliar o desempenho de herbáceas floríferas e substratos para uso em telhados verdes extensivos. O experimento foi realizado em campo e a pleno sol, em recipientes de plástico preto (8,46 L e 15,5 cm de altura), elevados a 90 cm do chão, em um esquema fatorial 3x2, sendo 3 espécies floríferas herbáceas (Torênia var. Kauai, Vinca var. Pacifica XP e Petúnia var. Bacopa) e 2 substratos [S1-Carvão vegetal + casca de pinus + turfa + vermiculita expandida (1v:1v:1v:1v) e S2- Fibra de coco + casca de arroz carbonizado + turfa + vermiculita expandida (1v:1v:1v:1v)], com 3 repetições por tratamento. Avaliou-se nos substratos: pH, condutividade elétrica, macro e microporosidade, porosidade total, densidade e capacidade de retenção de água. Para o desempenho das espécies, após 60 dias da instalação do experimento, foram avaliados: teor de clorofila das folhas, número de flores e temperatura superficial da vegetação. Observou-se que o substrato S2, apresentou os melhores resultados nas análises físico-químicas, e isso possivelmente veio a refletir no desempenho das espécies, sendo que Torênia quando cultivada nesse substrato, apresentou o maior teor de clorofila (42,67 SPAD). O número de flores foi estatisticamente igual para Torênia e Vinca em ambos substratos, já as três herbáceas floríferas apresentaram diminuição da temperatura superficial. Dessa forma, recomenda-se para uso em telhados verdes extensivos o substrato composto de Fibra de coco + casca de arroz carbonizado + turfa + vermiculita expandida (1v:1v:1v:1v), e a herbácea florífera Torênia var. Kauai. In general, extensive green roofs are defined as all cover covered with herbaceous vegetation and surface substratum, however, in Brazil there are few information regarding the materials for installation and maintenance of these systems, being essential the search for better species and substrates adapted to the tropical conditions. Thus, the objective was to evaluate the performance of floriferous herbaceous and substrates for use in extensive green roofs. The experiment was carried out in the field and in full sunlight, in black plastic containers (8.46 L and 15.5 cm high), elevated 90 cm from the ground, in a 3x2 factorial scheme. Being 3 herbaceous floriferous species (Torenia var. Kauai, Periwinkle var. Pacifica XP and Petunia var. Bacopa) and 2 substrates [S1-Charcoal + pine bark + peat + expanded vermiculite (1v:1v:1v:1v) and S2- Coconut fiber + carbonized rice husk + peat + expanded vermiculite (1v:1v:1v:1v)], with 3 replicates per treatment. It was evaluated in the substrates: pH, electrical conductivity, macro and microporosity, total porosity, density and water retention capacity. For the development of the species, 60 days after the experiment installation, were evaluated, chlorophyll content of leaves, number of flowers and vegetation surface temperature. It was observed that the substrate S2 presented the best results in the physico-chemical analyzes, and this possibly came to reflect on the performance of the species, and that Torenia when cultivated in this substrate had the highest chlorophyll content (42.67 SPAD). The number of flowers was statistically the same for Torenia and Periwinkle in both substrates, while the three floriferous herbaceous plants showed a decrease in surface temperature. Thus, it is recommended for use on extensive green roofs the substrate composed of coconut fiber + carbonized rice husk + peat + expanded vermiculite (1v:1v:1v:1v), and the floriferous herbaceous Torenia var. Kauai. Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas (FCA) Universidade Estadual Paulista (UNESP) Faculdade de Engenharia de Ilha Solteira (FEIS) Universidade Estadual Paulista (UNESP) Faculdade de Ciências Agronômicas (FCA) Universidade Estadual Paulista (UNESP) Faculdade de Engenharia de Ilha Solteira (FEIS)

Changes in the amount of mitochondrial DNA (mtDNA) have never been investigated in plant zygotes or early plant embryos due to the difficulty in isolating these cells, although such changes have been investigated in mammalian embryos. Using the single-cell quantitative real-time polymerase chain reaction (PCR) and laser confocal microscopy, we surveyed the changes in mtDNA levels during early embryogenesis in Torenia fournieri and Arabidopsis thaliana. In contrast with the amount of mtDNA in early mammalian embryos, which does not change, we found that mtDNA doubling occurred during zygotic development in T. fournieri and during two-cell proembryo development in A. thaliana. These findings reveal that mtDNA doubling occurs during early embryogenesis in T. fournieri and A. thaliana, indicating that the dynamics of mtDNA in early plant embryos differs from that in early mammalian embryos.

Wishbone flower (Torenia fournieri L.) is a common ornamental plant for flower bed in Taiwan. In August 2018, root and stem rot of wishbone flower occurred on the flower bed in the campus of Nation...

Summary The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal–ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC–RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal–ventral patterning and asymmetric corolla pigmentation in T. fournieri.

Key message Size limits on molecular movement among female gametes. Abstract Cellular decisions can be influenced by information communicated from neighboring cells. Communication can occur via signaling or through the direct transfer of molecules. Movement of RNAs and proteins has frequently been observed among symplastically connected plant cells. In flowering plants, the female gametes, the egg cell and central cell, are closely apposed within the female gametophyte. Here we investigated the ability of fluorescently labeled dyes and small RNAs to move from the Arabidopsis thaliana central cell to the egg apparatus following microinjection. These results define a size limit of at least 20 kDa for symplastic movement between the two gametes, somewhat larger than that previously observed in Torenia fournieri. Our results indicate that symplastic connectivity in Arabidopsis thaliana changes after fertilization and suggest that prior to fertilization mechanisms are in place to facilitate small RNA movement from the central cell to the egg cell and synergids.

Torenia fournieri Lind. ex Fourn. (wishbone flower, bluewings) is a popular summer bedding plant in Louisiana. Clown Mixture cultivars are available in garden centers in March and April. Transplants of cultivar Clown Rose were purchased, transplanted to larger pots, and maintained in a greenhouse. A powdery mildew was observed on these plants in March and all plants (six) were severely diseased by May. Symptoms included leaf distortion and yellowing. Powdery mildew was not present on transplants and none was found in later checks of garden centers. An Oidium sp. was observed sporulating on both leaf surfaces of infected plants. Conidia were ellipsoid, produced in chains, lacked fibrosin bodies, and averaged 41 × 22 μm in dimensions. No sexual stage was observed. Healthy plants of Clown Mixture cultivars were obtained and inoculated by brushing conidia from infected plant leaves to leaves of healthy plants. Plants were maintained in a greenhouse where temperatures ranged from 16 to 26°C. Hyphal growth appeared on inoculated plants after 5 days and the reproductive structures formed later appeared the same as those on originally infected plants. Uninoculated plants remained healthy. No previous reports of powdery mildew diseases of T. fournieri in the United States were found. Other powdery mildew pathogens reported on T. fournieri are Sphaerotheca fuliginea (Schlechtend.:Fr.) Pollacci in Finland and Japan and an Erysiphe sp. in Japan (1). Reference: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Press, Tokyo, 1986.

Torenia fournieri (Linderniaceae) is a common ornamental plant in China. It is also an important Chinese medicinal herb for its heart clearing and toxin removal properties. In October 2013, severe powdery mildew infections were observed on T. fournieri in Baihuayuan Garden (125.35°E, 43.88°N), China. Voucher specimens were deposited in the Herbarium of Mycology of Jilin Agricultural University under the accession number HMJAU02176. Whitish colonies covered the surface of leaves, petioles, sepals, and stems. The infected leaves became yellow and necrotic by advanced stages of the infection. Chasmothecia with a diameter between 63.5 and 95 μm were present singly or in groups, and bore dark brown mycelioid. The appendages were 0.5 to 4 times as long as the chasmothecial diameter, brown at the base and paler toward the apex. Asci were 2 to 6 per chasmothecium, short-stalked or sessile, 50 to 62 × 30 to 50.5 μm, and 2- to 4-spored. Ascospores were pale brown, oval to ellipsoid, 27 to 43 × 13 to 17 μm. Hyphae were flexuous to straight, branched, and septate. Appressoria were well-developed, lobed, and solitary or in opposite pairs. Conidiophores were unbranched, cylindrical, and 94 to 185 × 9 to 15 μm. Foot-cells were straight, cylindrical, 19 to 40 μm long, and followed by 1 to 3 cells shorter or nearly equal to the foot-cell. Conidia were singly produced, cylindrical or oval, 34 to 44 × 16 to 20 μm, and without distinct fibrosin bodies. Lobed germ tubes were produced at the tip of conidia. The morphological characteristics of sexual and asexual structures were consistent with Erysiphe macleayae (1,2). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of the pathogen was amplified with the primers ITS1/ITS4 and sequenced (3). The resulting 574-bp sequence (KJ600796) showed 100% similarity with E. macleayae (KF856294) and Oidium sp. isolated from Chelidonium majus (HQ286645 to 46) and one base different from M. microcarpa (JQ681217). Koch's postulate was completed by gently pressing a diseased leaf onto three young excised leaves of asymptomatic seedlings. Three non-inoculated leaves were used as controls. Inoculated leaves were incubated in separate petri dishes in a greenhouse at 20 to 25°C. Symptoms developed 5 days after inoculation, whereas the control leaves remained symptomless (voucher specimens HMJAU02176I). The morphology of the fungus on the inoculated leaves was identical to that observed on the originally diseased leaves. Powdery mildew on T. fournieri has only been reported as Golovinomyces sp. in Hungary (4). To our knowledge, this is the first report of powdery mildew caused by E. macleayae on T. fournieri worldwide. Infection of Torenia by E. macleayae, a common powdery mildew on various hosts of the Papaveraceae, is very unusual and unexpected. It demonstrates a wider host range of this species beyond the limits of the Papaveraceae. References: (1) U. Braun and R. T. A. Cook. Taxonomic manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series 11. CBS, Utrecht, the Netherlands, 2012. (2) M. J. Park et al. Plant Dis. 96:1376, 2012. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) P. Vági et al. Eur. J. Plant Pathol. 117:89, 2007.

Successful fertilization in flowering plants depends on the precise directional growth control of pollen tube through the female pistil tissue toward the female gametophyte contained in the ovule for delivery of nonmotile sperm cells. Cys-rich peptides LUREs secreted from the synergid cells on either side of the egg cell act as ovular attractants of pollen tubes. Competency control by the pistil is crucial for the response of pollen tubes to these ovular attractants. We recently reported that ovular 4-O-methyl-glucuronosyl arabinogalactan (AMOR) induces competency of the pollen tube to respond to ovular attractant LURE peptides in Torenia fournieri. The beta isomer of the terminal disaccharide 4-O-methyl-glucuronosyl galactose was essential and sufficient for the competency induction. However, critical and noncritical structures in the disaccharide have not been dissected deeply. Herein, we report the synthesis of new AMOR analogs and the structure-activity relationships for AMOR activity in the presence of these synthesized analogs. Removal of 4-O-methyl group or –COOH from the glucuronosyl residue of the disaccharide dramatically reduces AMOR activity. The pyranose backbone of the second sugar of disaccharide is essential for the activity but not hydroxy groups. The role of beta isomer of the disaccharide 4-Me-GlcA-β(1,6)-Gal is very specific for competency control, as there was no difference in effect among the sugar analogs tested for pollen germination. This study represents the first structure-activity relationship study, to our knowledge, of a sugar molecule involved in plant reproduction, which opens a way for modification of the molecule without loss of activity.

Precise directional control of pollen-tube growth by pistil tissue is critical for successful fertilization of flowering plants [1-3]. Ovular attractant peptides, which are secreted from two synergid cells on the side of the egg cell, have been identified [4-6]. Emerging evidence suggests that the ovular directional cue is not sufficient for successful guidance but that competency control by the pistil is critical for the response of pollen tubes to the attraction signal [1, 3, 7]. However, the female molecule for this competency induction has not been reported. Here we report that ovular methyl-glucuronosyl arabinogalactan (AMOR) induces competency of the pollen tube to respond to ovular attractant LURE peptides in Torenia fournieri. We developed a method for assaying the response capability of a pollen tube by micromanipulating an ovule. Using this method, we showed that pollen tubes growing through a cut style acquired a response capability in the medium by receiving a sufficient amount of a factor derived from mature ovules of Torenia. This factor, named AMOR, was identified as an arabinogalactan polysaccharide, the terminal 4-O-methyl-glucuronosyl residue of which was necessary for its activity. Moreover, a chemically synthesized disaccharide, the β isomer of methyl-glucuronosyl galactose (4-Me-GlcA-β-(1→6)-Gal), showed AMOR activity. No specific sugar-chain structure of plant extracellular matrix has been identified as a bioactive molecule involved in intercellular communication. We suggest that the AMOR sugar chain in the ovary renders the pollen tube competent to the chemotropic response prior to final guidance by LURE peptides.

Torenia fournieri E. Fourn., known as torenia or clown flower, is an annual plant in the Linderniaceae. In October 2014, typical powdery mildew symptoms were observed on torenia plants of an unknown cultivar in a private garden in Seongnam (37°26′50″N; 127°10′02″E), Korea. In August 2019, dozens of torenia of an unknown cultivar planted in shady borders of a roadside garden in Seoul (37°34′46″N; 127°01′25″E), Korea, were found to be infected with a powdery mildew with 100% disease incidence. Signs first appeared as circular to irregular white patches, which subsequently coalesced to develop into abundant hyphal growth on both sides of the leaves and also on flower stalks and calyxes. As the disease developed, affected leaves became wilted. Two voucher specimens have been deposited in the Korea University Herbarium (KUS-F28526 and F31142). Hyphal appressoria were nipple shaped or indistinct. Conidiophores were cylindrical, 110 to 240 × 10 to 12 µm, and had cylindrical foot cells, somewhat curved at the base, and 50 to 100 μm long, followed by two short cells and two to six immature conidia in chains with a sinuate outline. Conidia were hyaline, ellipsoid to barrel shaped, 26 to 38 × 16 to 22 μm (length/width ratio = 1.4 to 2.0), and devoid of distinct fibrosin bodies. Germ tubes were perihilar on the conidia. These morphological characteristics are consistent with those of Golovinomyces bolayi (Schwein.) U. Braun & R.T.A. Cook (Braun and Cook 2012). No chasmothecia were found during the growing season. To confirm identification, the internal transcribed spacer region of rDNA of KUS-F28526 was amplified with primers ITS1/ITS4 and sequenced. The resulting sequence was deposited in GenBank (accession no. MN420661). A GenBank BLAST search revealed a sequence similarity of 99.7% to G. bolayi ex Torenia fournieri (DQ538345). A pathogenicity test was performed by gently dusting conidia onto leaves of five healthy potted plants bought in a flower market. Five noninoculated plants served as controls. Powdery mildew colonies developed on all inoculated leaves after 7 to 10 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was identical morphologically to that observed on the originally diseased leaves. The pathogenicity test was performed twice with similar results. Previously, G. bolayi on T. fournieri was known from Hungary (Braun et al. 2019). Two previous records of Oidium sp. on T. fournieri from Japan (Wada and Hirata 1977, figure plates uploaded on November 2008 and shown at www.naro.affrc.go.jp) and the United States (Holcomb 1999) are likely to be Golovinomyces, probably G. bolayi. To our knowledge, this is the first report of powdery mildew caused by G. bolayi on T. fournieri in Korea. Because powdery mildew infection detracts from the beauty and health of green leaves, control measures should be developed.

This study was conducted to examine the role of the transcription factors (TFs), RsMYB1 and mPAP1 together with B-Peru (mPAP1 + B-Peru), in regulating anthocyanin biosynthesis in the ornamental torenia (Torenia fournieri) cultivar Kauai Rose using Agrobacterium-mediated transformation. Expression levels of RsMYB1 were the highest in the lines RS5 and RS3, followed by RS4, RS2, and RS1, while transcript levels of mPAP1 + B-Peru increased in the order of PB-6 > PB-5 > PB-7 > PB-8 > PB-2. Moreover, transcript levels of the anthocyanin structural genes in transgenic lines were significantly higher than those in wild-type (WT) plants. Anthocyanin structural gene expression was specifically altered by TF overexpression: the highest expression of anthocyanidin synthase (ANS) was observed in transgenic lines with RsMYB1, while expression of dihydroflavonol-4-reductase (DFR) was the highest in lines with mPAP1 + B-Peru. We expect that enhanced expression of these anthocyanin structural genes will improve anthocyanin content in the flowers of transgenic torenia. Moreover, these results indicate that RsMYB1 and mPAP1 + B-Peru can be exploited as anthocyanin regulatory TFs to enhance anthocyanin content in other horticultural plants. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-018-1505-7) contains supplementary material, which is available to authorized users.

We present a semi-in vitro chemotropism assay that can be used to evaluate the chemoattractant effect of diffusible plant signaling molecules on growing pollen tubes. We constructed an array of microslit channels in a microfluidic device that prevented the passage of randomly growing pollen tubes but permitted ones that are responsive to the chemoattractant. Depending on the microslit channel size, 80%–100% of the randomly growing Torenia fournieri pollen tubes were excluded from reaching the source of the attractant. Thus, the selection of pollen tubes that are capable of responding to chemoattractants from a mixed population can be realized using this platform.

Background ALOG (Arabidopsis LSH1 and Oryza G1) family with a conserved domain widely exists in plants. A handful of ALOG members have been functionally characterized, suggesting their roles as key developmental regulators. However, the evolutionary scenario of this gene family during the diversification of plant species remains largely unclear. Methods Here, we isolated seven ALOG genes from Torenia fournieri and phylogenetically analyzed them with different ALOG members from representative plants in major taxonomic clades. We further examined their gene expression patterns by RT-PCR, and regarding the protein subcellular localization, we co-expressed the candidates with a nuclear marker. Finally, we explored the functional diversification of two ALOG members, TfALOG1 in euALOG1 and TfALOG2 in euALOG4 sub-clades by obtaining the transgenic T. fournieri plants. Results The ALOG gene family can be divided into different lineages, indicating that extensive duplication events occurred within eudicots, grasses and bryophytes, respectively. In T. fournieri, seven TfALOG genes from four sub-clades exhibit distinct expression patterns. TfALOG1–6 YFP-fused proteins were accumulated in the nuclear region, while TfALOG7-YFP was localized both in nuclear and cytoplasm, suggesting potentially functional diversification. In the 35S:TfALOG1 transgenic lines, normal development of petal epidermal cells was disrupted, accompanied with changes in the expression of MIXTA-like genes. In 35S:TfALOG2 transgenic lines, the leaf mesophyll cells development was abnormal, favoring functional differences between the two homologous proteins. Unfortunately, we failed to observe any phenotypical changes in the TfALOG1 knock-out mutants, which might be due to functional redundancy as the case in Arabidopsis. Conclusion Our results unraveled the evolutionary history of ALOG gene family, supporting the idea that changes occurred in the cis regulatory and/or nonconserved coding regions of ALOG genes may result in new functions during the establishment of plant architecture.

We developed a fertilization method in which pollen tubes entered into embryo sacs without any need to contact surrounding female sporophytic cells by using Torenia fournieri (Torenia) plants under the condition of hindering movement of the virus from a stigma, which is the first infection site leading to systemic infection. When RBDV-infected Torenia pollen grains were used for the developed fertilization method, the virus was transmitted to the seeds by pollen tubes germinating from them. On the other hand, no seeds were infected with the virus when Torenia plants were pollinated with healthy Torenia pollen grains in combination with RBDV-infected raspberry pollen grains, which caused the virus infection in the stigma by penetration of their pollen tubes arrested in its style. Our results indicate that vertical transmission of RBDV by pollen occurs in the transport of the virus into embryo sacs by pollen tubes reaching the embryo sacs.

The female gametophytes of many flowering plants contain one egg cell, one central cell, two synergid cells and three antipodal cells with respective morphological characteristics and functions. These cells are formed by cellularization of a multinuclear female gametophyte. However, the dynamics and mechanisms of female gametophyte development remain largely unknown due to the lack of a system to visualize directly and manipulate female gametophytes in living material. Here, we established an in vitro ovule culture system to examine female gametophyte development in Torenia fournieri, a unique plant species with a protruding female gametophyte. The four-nucleate female gametophyte became eight nucleate by the final (third) mitosis and successively cellularized and matured to attract a pollen tube. The duration of final mitosis was 28 ± 6.5 min, and cellularization was completed in 54 ± 20 min after the end of the third mitosis. Fusion of polar nuclei in the central cell occurred in 13.1 ± 1.1 h, and onset of expression of LURE2, a pollen tube attractant gene, was visualized by a green fluorescent protein reporter 10.7 ± 2.3 h after cellularization. Laser disruption analysis demonstrated that the egg and central cells were required for synergid cells to acquire the pollen tube attraction function. Moreover, aberrant nuclear positioning and down-regulation of LURE2 were observed in one of the two synergid cells after disrupting an immature egg cell, suggesting that cell specification was affected. Our system provides insights into the precise dynamics and mechanisms of female gametophyte development in T. fournieri.