Prunus Serrulata Research Articles

First Report of Phytopythium vexans Causing Root and Crown Rot on Flowering Cherry in Tennessee.

Flowering cherry (Prunus serrulata Lindl. 'Kwanzan') rooted cuttings grown in propagation beds containing 40% coarse sand and 60% ground pine bark in a commercial propagation nursery in Warren County, Tennessee were exhibiting root and crown rot in December 2016. Dark brown to black soft lesions were observed in the roots as well as the crown region of flowering cherry rooted cuttings and those rooted cuttings were non-marketable due to lesions. Disease incidence was approximately 60% of 10,000 plants. Phytophthora ImmunoStrip test (Agdia Inc., Elkhart, IN, USA) was performed and the test result was positive. Diseased plant tissues were surface sterilized with 70% ethanol and washed twice with distilled water. Culturing the affected root and crown parts (1 cm pieces) on V8-PARPH, an oomycete-selective medium consistently yielded whitish radiate mycelial growth pattern with spherical zoospores, filamentous to globose oogoni, elongated, and cylindrical antheridia with constrictions (De Cock et al., 2015) after 7 days of incubation at 25°C in a 12-h fluorescent light and dark cycle, which is the typical morphology of Phytopythium vexans (de Bary) Abad, de Cock, Bala, Robideau, Lodhi & Lévesque. To confirm pathogen identity, total DNA was extracted using the UltraClean Microbial DNA Isolation Kit (MO BIO Laboratories, Inc., Carlsbad, CA, USA) directly from a 3-day old culture of isolate (FBG2017010) on V8 medium. The internal transcribed spacer (ITS) and 28S large subunit of ribosomal RNA, and cytochrome c oxidase subunit I (CoxI) of mitochondrial DNA (mtDNA) genes/ region were amplified by PCR using the primer pairs ITS1/ ITS4 (White et al., 1990), NL1/ NL4 (Baten et al., 2014), and Levup and Fm85mod (Robideau et al., 2011), respectively. The PCR products were sequenced and the sequences (GenBank accession nos. MT533275, MT533451, and MT547980) were compared to the voucher specimens. They were 99.23, 99.60, and 98.92% similar to those of P. vexans isolates in the NCBI database (HQ643400, KR092144, and HQ708996, respectively). To complete Koch's postulates, 'Kwanzan' flowering cherry rooted cuttings grown on propagation substrate (10 cm pot containing 1 kg sterilized 40% coarse sand and 60% ground pine bark) were inoculated with identified pathogen and observations were taken on root rot disease symptoms. Five plants were inoculated with 100 ml of pathogen agar-slurry (1 plate of a 7-day old culture of isolate FBG2017010/1 L of sterilized water), and five control plants were drenched with agar slurry. The plants were maintained in the greenhouse condition (day/night temperature of 26/24°C), and irrigated twice a day for 2 min by overhead irrigation system. After 2 weeks, dark brown to black necrotic root lesions developed on all inoculated cuttings and P. vexans was consistently re-isolated from the inoculated plants. The morphology of the pathogen isolated on the V8-PARPH medium was identical to the original isolate. All control plants remained symptom-free and P. vexans was not isolated from the root tissue. To our knowledge, this is the first report of P. vexans causing root and crown rot in 'Kwanzan' flowering cherry in Tennessee, which can be a potential threat for the nursery crop production. The identification of P. vexans, the causal agent of Phytopythium root and crown rot is important in determination and implementation of effective management strategies.

X‐ray computed tomography of severed root wounds of Prunus serrulata and Zelkova serrata

AbstractThe performance of laboratory X‐ray computed tomography (XCT) for the non‐destructive imaging of root wood was evaluated. Lateral roots of oriental cherry (Prunus serrulata var. spontanea) and Japanese zelkova (Zelkova serrata) were severed in spring and maintained in soil for 6 months. Without sectioning, XCT revealed the phloem, xylem and vascular cambium structures in the root wood. A virtual transverse section showed a ring of woundwood covering the severed, lateral root of the two trees. Different levels of X‐ray absorption were evident around the cut surfaces of P. serrulata; however, they were rarely detected in Z. serrata. More adventitious roots were observed on Z. serrata than on P. serrulata. Distinct white spots in the rays were only detected in Z. serrata. These results suggest that XCT has potential applications in forest pathology, providing virtual sections of wound closure, wood density distribution, organ redifferentiation, and mineral deposition in root wood.

The complete chloroplast genome of native Prunus campanulata in Taiwan

Prunus campanulata was a native flowering cherry tree with burgundy red flowers in Taiwan. In this study, the complete chloroplast (cp) genome of P. campanulata was determined. The length of P. campanulata cp genome is 157,938 bp. A total of 130 genes are comprised of 86 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. The overall GC content of cp genome was 36.72%. A maximum-likelihood phylogenetic analysis revealed that P. campanulata is closed to Prunus serrulata. The cp genome sequence is useful for further genetic, evolutionary, and breeding researches.

First identification of cucumber mosaic virus in Prunus serrulata, Photinia serrulata, Begonia semperflorens and Osmanthus matsumuranus

Infection with cucumber mosaic virus (CMV) has resulted in important economic losses in many crops worldwide. In this study, CMV was detected from Prunus serrulata, Photinia serrulata, Begonia semperflorens and Osmanthus matsumuranus by RT-PCR and Western blot, when eleven kinds of horticultural plants from three provinces were screened. This is the first report of CMV naturally infecting these four species of horticultural plants. In addition, CMV isolates from southwest China presented regional differences to isolates from other parts of China based on phylogenetic analysis.

Space and Cherry Blossom Viewing Users of ‘Kawazu Zakura’ (Prunus lannesiana. Wils.) Noted Place at Lower Kawazu River Basin in Izu Peninsula

Space and Cherry Blossom Viewing Users of ‘Kawazu Zakura’ (Prunus lannesiana. Wils.) Noted Place at Lower Kawazu River Basin in Izu Peninsula

Complete chloroplast genome of the wild Japanese Mountain cherry (Prunus jamasakura, Rosaceae)

Prunus jamasakura is a species of Prunus native to eastern Asia. We determined the first complete chloroplast genome of Prunus jamasakura using genome skimming approach. The cp genome was 157,905 bp long, with a large single-copy region (LSC) of 85,910 bp and a small single-copy region (SSC) of 19,123 bp separated by a pair of inverted repeats (IRs) of 26,436 bp. It encodes 129 genes, including 84 protein-coding genes, 37 tRNA genes, and 8 ribosomal RNA genes. We also reconstructed the phylogeny of Prunus sensu lato using maximum likelihood (ML) method, including our data and previously reported cp genomes of related taxa. The phylogenetic analysis indicated that P. jamasakura is closely related with Prunus speciosa.

Prunus serrulata var. spontanea inhibits mast cell activation and mast cell-mediated anaphylaxis.

A promising approach to treat a variety of diseases are considered as complementary and alternative herbal medicines. Prunus serrulata var. spontanea L. (Rosaceae) is used as herbal medicine to treat allergic diseases according to the Donguibogam, a tradition medical book of the Joseon Dynasty in Korea. We prepared the aqueous extract of the bark of P. serrulata (AEBPS) and aimed to investigate the effects in mouse anaphylaxis models and various types of mast cells, including RBL-2H3, primary cultured peritoneal and bone marrow-derived mast cells. We used ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) and immunoglobulin (Ig) E-mediated passive cutaneous anaphylaxis (PCA) models, in vivo. The control drug dexamethasone (10mg/kg) was used to compare the effectiveness of AEBPS (1-100mg/kg). In vitro, IgE-stimulated mast cells were used to confirm the role of AEBPS (1-100μg/mL). For statistical analyses, p values less than 0.05 were considered to be significant. In ASA model, oral administration of AEBPS suppressed the hypothermia and increased level of serum histamine in a dose-dependent manner. AEBPS attenuated the serum IgE, OVA-specific IgE, and interleukin (IL)-4. Oral administration of AEBPS also blocked mast cell-dependent PCA. AEBPS suppressed degranulation of mast cells by reducing intracellular calcium level in mast cells. AEBPS inhibited tumor necrosis factor-α and IL-4 expression and secretion in a concentration-dependent manner through the reduction of nuclear factor-κB. On the basis of these findings, AEBPS could serve as a potential therapeutic target for the management of mast cell-mediated allergic inflammation and as a regulator of mast cell activation.

Epitypification of Prunus × nudiflora (Rosaceae), a natural hybrid species in Jeju Island, Korea

Prunus × nudiflora is an endemic species to Jeju Island, South Korea and economically important as ornamentals. According to recent molecular phylogenetic and genomic studies, this species is revealed as a F1 hybrid originating from a cross between maternal Prunus pendula f. ascendens and paternal Prunus jamasakura. However, the plate specimen designated as type materials of P. × nudiflora does not permit a precise application of the name because of its poor condition. The herbarium specimens related with that illustration were examined to clarify the identity of P. × nudiflora, and an epitype is selected. Our epitypification proposed here will ensure nomenclatural accuracy for most material from cultivation, where the name P. × nudiflora is widely used.

Infection scene investigation of shot holes: Incomplete but neutral abscission of brown spots on oriental cherry leaves

AbstractShot holes on oriental cherry (Prunus serrulata var. spontanea) leaves were investigated to evaluate their role in the elimination of pathogens using analytical electron microscopy. Small brown spots caused by Mycosphaerella cerasella appeared on the leaf surface and developed into shot holes that were approximately 1–5 mm in diameter. Field emission scanning electron microscopy revealed clusters of fungal conidiophores and hyphal growth on the leaf surface around the shot holes. The fungal structures were mostly located within a radius of 500 μm from the shot holes and confined to the epidermal sector separated by veins. X‐ray microanalysis revealed distinct calcium ring patterns encircling the shot holes. The abscised surfaces consisted of suberized plant cells colonized with filamentous fungi and yeasts. Embedded in the mesophyll tissue, druse crystals were co‐localized with calcium and oxygen. Despite the fungal presence around the shot holes, no further expansion of the shot holes was observed on the leaf surface. These results suggest that shot holes may represent an incomplete but neutral abscission of infection loci in the presence of necrotrophic fungal pathogens. This microscopy study provides insight into the formation and roles of calcium oxalate in plants under pathological conditions.

Wood volatiles as attractants of the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae)

Confused flour beetles are serious pests of stored grain products, and therefore, it is important to efficiently monitor and control their populations. Aggregation pheromones are commercially used for monitoring this beetle but their efficacy has been questioned and they may be inadequate for practical use. Food attractants as well as pheromones are commonly used for monitoring stored-product insects. However, food attractants may not be effective in the case of food handling facilities, which are already filled with food odours. The ancestors of flour beetles may have been associated with dead or decomposing woody vegetation, so we investigated the attractiveness of several wood odours to beetles using a pitfall olfactometer. The beetles were strongly attracted to all wood odours tested: Castanea crenata, Magnolia obovata, Paulownia tomentosa, Prunus jamasakura, and Zelkova serrata. The attractiveness of these wood odours was also stronger than that of the odours of the usual food of these beetles. Supercritical CO2 extracts of these species of wood were also attractive to the beetles. The Z. serrata extract was the most attractive among these extracts, and was further analysed by gas chromatography mass spectrometry. One major compound, (−)-mellein, was detected in the extract. Synthetic (±)-mellein attracted the beetles.

Damage to leaf veins suppresses root foraging precision.

Plants generally increase root growth in areas with high nutrients in heterogeneous soils, a phenomenon called foraging precision. The physiology of this process is not well understood, but it may involve shoot-root signaling via leaf veins. If this is true, then damage to leaf veins, but not to nearby mesophyll, would reduce plant foraging precision. To test this hypothesis, we imposed two leaf damage treatments on Plantago asiatica and Prunus jamasakura, removing either the tip of each main vein or mesophyll tissue between the veins with a 3-mm-diameter hole punch. After 30 days or 20 weeks of plant growth, we measured root biomass in the soil in response to soil nutrient concentration. When leaf mesophyll was damaged, root biomass of both species was greater in nutrient-rich patches than in nutrient-poor patches. However, when leaf veins were damaged, root biomass was similar between patches. These results suggest the importance of shoot-root signaling in plants, emphasizing that physiological processes are not necessarily restricted to single organs. The idea that herbivores that damage leaf veins may affect a plant's ability to selectively forage in high-nutrient patches is novel, with implications for natural and managed systems.

The complete chloroplast genome of Prunus apetala, a native deciduous flowering cherry of Japan

The complete chloroplast (cp) genome of Prunus apetala was determined. The length of the cp genome of P. apetala is 157,987 bp. A total of 129 genes are comprised of 84 protein-coding genes, 37 tRNA genes, and 8 rRNA ribosomal genes. The overall GC content of cp genome is 36.7%. The phylogenetic position of P. apetala is sister to Prunus serrulata var. spontanea.

Genetic insights into the modification of the pre-fertilization mechanisms during plant domestication.

Plant domestication is the process of adapting plants to human use by selecting specific traits. The selection process often involves the modification of some components of the plant reproductive mechanisms. Allelic variants of genes associated with flowering time, vernalization, and the circadian clock are responsible for the adaptation of crops, such as rice, maize, barley, wheat, and tomato, to non-native latitudes. Modifications in the plant architecture and branching have been selected for higher yields and easier harvests. These phenotypes are often produced by alterations in the regulation of the transition of shoot apical meristems to inflorescences, and then to floral meristems. Floral homeotic mutants are responsible for popular double-flower phenotypes in Japanese cherries, roses, camellias, and lilies. The rise of peloric flowers in ornamentals such as snapdragon and florists' gloxinia is associated with non-functional alleles that control the relative expansion of lateral and ventral petals. Mechanisms to force outcrossing such as self-incompatibility have been removed in some tree crops cultivars such as almonds and peaches. In this review, we revisit some of these important concepts from the plant domestication perspective, focusing on four topics related to the pre-fertilization mechanisms: flowering time, inflorescence architecture, flower development, and pre-fertilization self-incompatibility mechanisms.

Nectar and pollen production in ornamental cultivars of Prunus serrulata (Rosaceae)

Abstract Planting ornamental species can help to create pollinator-friendly habitats. In the present study the flowering phenology and floral reward (nectar and pollen) in two cultivars of Prunus serrulata (‘Kanzan’ and ‘Amanogawa’) were evaluated in 2014-2015 in the city of Lublin (south-east Poland). On average, the onset of flowering of P. serrulata occurred in the first ten days of April (‘Kanzan’) or at the end of April (‘Amanogawa’), and lasted 8-17 days. In each year of the study, P. serrulata ‘Kanzan’ started flowering 11-18 days earlier than P. serrulata ‘Amanogawa’. The double flowers of P. serrulata ‘Kanzan’ offered only tiny amounts of nectar and pollen. The total mass of sugars was 0.59 mg per flower and that of pollen 0.08 mg per flower. The semi-double flowers of P. serrulata ‘Amanogawa’ produced 4.5 mg of sugars per flower and 0.17 mg of pollen per flower. The frequency of pollinator visits to flowers was low in P. serrulata ‘Amanogawa’ and very low in P. serrulata ‘Kanzan’. Therefore, if pollinator-friendly arrangements are made in urban areas, these cultivars should not be planted.

The Sustainability of Ohanami Cherry Blossom Festivals as a Cultural Icon

Background: One important form of sustainability is the continuation of culture and cultural practices. This study examined the case of Japanese Ohanami or cherry blossom festivals. Historically, Ohanami focused on the cherry blossom as a symbol of spring’s arrival, where communal aspects, consumption of sake and seasonal foods, painting or photography, and pilgrimages to sacred sites were used to celebrate the ephemeral aspects of blossoms, spring, and life. Methods: This study examines how cherry blossom festivals are celebrated and understood and how these celebrations are changing. Results: Current celebrations demonstrate several forces are changing this celebration. The changes in cherry blossom festivals are seen in four areas (bonding, cultural continuity, marketing exploitation, and cultural symbolism). Cherry blossom festivals are also observed overseas—at first glance this suggests its continuity, however, the ways in which Ohanami is observed raise concerns about the accuracy of this cultural practice. Conclusion: Ohanami celebrations are celebrated both in Japan and overseas, and although their practice continues, the nature of the cultural celebrations are changing.

Estimation of Individual Tree Health Condition for Japanese Mountain Cherry (Cerasus jamasakura) Using Airborne LiDAR

This study examined the usefulness of airborne light detection and ranging (LiDAR) data for estimating the individual tree health condition in Japanese mountain cherry (Cerasus jamasakura) in Yoshinoyama, Nara Prefecture, Japan. LiDAR variables that represented the ratio of lasers hitting tree components were calculated and their effectiveness was examined by relating them to the results of conventional field-based visual tree health assessments based on ordination, correlation analyses, and generalized linear models. The results showed that many of the LiDAR variables had significant correlations with the variables derived from visually evaluated tree health condition. In particular, the proportion of “only” returns, which represents the ratio of the lasers reflected from the crown surfaces, was the most effective for estimating total health condition in relation to the crown density, one of the key health indicators for representing physical properties. The individuals with large estimation errors had smaller crowns than the individuals with small errors, suggesting that sufficiently large crown sizes are important for more accurate estimations of the tree health condition using airborne LiDAR data.

A Practical and Efficient Method for the Micropropagation of Japanese Cherry (Prunus sp.)

This study was conducted to establish the procedure for in vitro propagation of Japanese cherry (Prunus sp.) to produce large quantity of plantlets and initial planting materials for climate adaptation research of this plant in Hanoi. Single nodal stems were used as the primary explants and initially produced shoots on MS medium supplemented with 1 mg L-1 BA. The highest shoot multiplication rate (9.57 times) was obtained on MS medium containing 1 mg L-1 BA and 0.25 mg L-1 a-NAA after 8 weeks of culture. 100% of the shoots produced roots with a mean of 10.10 roots per plant within 4 weeks on ½ MSM medium with 4 mg L-1 IBA. The survival rate of in vitro derived plantlets after a 6 to 7-week-period of rooting during acclimatization using a soil: coco peat: smoked rice husks (2:2:1, v/v/v) substrate was 100% and acclimatized plantlets showed good growth and development. This is the first report on a practical and efficient in vitro multiplication protocol for Japanese cherry in Vietnam, starting from shoot initiation to establishment of plants under greenhouse conditions.

New ornamental cherry cultivars induced by heavy-ion beam irradiation

We have developed a unique technology for mutation induction using heavy-ion beams. The irradiation treatment is quick, lasting between a few seconds and a few minutes, and is sufficient to induce mutation. Some new cherry blossom cultivars have already been introduced to the market. Pale-yellow cherry blossom ‘Nishina Zao’ was created by irradiating greenish ‘Gyoiko’ (Prunus lannesiana) scions with carbon ions. Unlike normal cherry blossom trees (P. pauciflora ‘Keio-zakura Yamagata No.13’), ‘Nishina Otome’ does not require a certain period under cold winter weather to induce flowering in the spring. Both cultivars are propagated by cloning branches of mutant plants. We have also succeeded in creating new cultivars using progeny of irradiated plants that are not changed with respect to either flower color or shape. Although the original cultivar, P lannesiana ‘Beni-yutaka’, has a double flower with 15-20 petals, the new cultivar ‘Nishina Tomoka’ has a large, single flower with 5 petals. Heavy-ion beams are thus effective tools for creating new variations of Prunus trees through mutation breeding.

Anatomical and histochemical studies of maturation and the accumulation of polysaccharides or volatile organic compounds in Japanese wild cherry fruit following ethephon application

The leaf of the Japanese wild cherry, Prunus Sato-zakura Group, especially ‘Oshima-zakura’, releases volatile organic compounds (VOCs) such as polysaccharides or coumarin from the leaves or fruits. These substances have a pleasant smell and exert a bactericidal effect. However, little information is available on the maturation and development of fragrant ingredients in ‘Oshima-zakura’ fruit. In this study, we used histochemistry to observe polysaccharide or VOC release from the fruit tissue. Ethephon (500 ppm) was sprayed on immature green fruit. Fruit samples were obtained at the immature (green), turning (red), and matured (black) stages. Fruit ripening proceeded about 3 to 5 days after ethephon application. The surface cells of the fruit epicarp were composed of a thick cuticle with wax, and two to three layers of cells were found underneath the cuticle, which contained chloroplast during the immature stage. As the fruit matured, these cells developed vacuoles in the epicarp tissue and anthocyanin accumulated significantly following ethephon application. When stained with toluidine blue-O, cells of the fruit mesocarp tissue exhibited a red-purplish colour following treatment with ethephon. This indicated that cells of the mesocarp contained polysaccharide, such as pectic substances or VOCs, especially coumarin. Accordingly, the substances that stained red-purplish may be antifungal and may exhibit antifeedant properties against pests. We conclude that polysaccharides or VOCs, especially coumarin, may increase the functional potential of wild cherry in addition to its fragrant properties, following treatment with ethephon.

Variations in flower differentiation period and flowering time in Japanese cherry cultivars

Flowering time affects the ornamental value of trees producing cherry blossoms and is important for successful pollination, ensuring high fruit production in cherry trees. We recorded the time to full bloom and inflorescence architecture characteristics of 138 flowering cherry cultivars and two fruiting cherry cultivars grown at Shimane University, Japan (35°30'37”N), and analyzed the relationships among measurement parameters. Late-blooming cultivars tended to form larger inflorescences, with more flowers per cluster. We performed comparative observations of flower differentiation in seven cultivars with different inflorescence architecture characteristics at flowering time. Interestingly, the flower differentiation period was related to neither flowering time nor inflorescence architecture. For example, the very early-blooming cultivar 'Kawazu-zakura', which typically reaches full bloom in mid-March, initiates flower primordia in September and completes flower bud differentiation at the end of September. Flower differentiation occurred later in 'Kawazu-zakura' than in other cultivars. In contrast, the late-blooming cultivar 'Tsukubane', which reaches full bloom in late April, experienced flower bud differentiation in August. In most of the cultivars observed, the number of initiated flower primordia in buds at flower differentiation exceeded the number of flowers in an inflorescence at flowering. Approximately one flower primordium was observed to have degenerated during dormancy or before flowering. Although the factors affecting floral initiation are unknown, a significant difference in the timing of flower differentiation among cultivars may indicate genetic control over the timing of flower differentiation, which is unrelated to bud dormancy regulation.