Sphaerotheca Pannosa Research Articles

Field Book: use in phenotypic data collection in rose breeding

Phenotypic evaluation of genotypes has traditionally been done by plant breeders using a pen and paper. Most breeding programs record data on paper then later enter it into spreadsheets. However, this traditional method permits more mistakes in data entry and delays the accessibility of the data to the breeder for analysis. Previous attempts at data collection directly into spreadsheets has proved cumbersome and ineffective at replacing the antiquated methods of pen and paper. Field Book, an open source Android application developed for the collection of phenotypic data of wheat germplasm by Trevor Rife and Jesse Poland at Kansas State University, has been successfully adopted for phenotypic data collection in the Texas A&M Rose Breeding and Genetics Program. The software loaded on an Android powered tablet or a phone is used to collect phenotypic data of garden roses looking at traits of flower intensity, disease severity [black spot (Diplocarpon rosae), cercospora (Cercospora rosicola), and powdery mildew (Podosphaera pannosa)], defoliation, flower rating, flower cleaning, overall landscape ranking, along with any additional breeder notes associated with disease and/or growth patterns. Furthermore, pictures taken are automatically associated with the plant being evaluated. The use of Field Book has saved time and has avoided transcription errors by exporting the data directly to spreadsheets bringing phenotypic data collection fully into the computer age.

Interaction of roses with a biotrophic and a hemibiotrophic leaf pathogen leads to differences in defense transcriptome activation

Key messageTranscriptomic analysis resulted in the upregulation of the genes related to common defense mechanisms for black spot and the downregulation of the genes related to photosynthesis and cell wall modification for powdery mildew.Plant pathogenic fungi successfully colonize their hosts by manipulating the host defense mechanisms, which is accompanied by major transcriptome changes in the host. To characterize compatible plant pathogen interactions at early stages of infection by the obligate biotrophic fungus Podosphaera pannosa, which causes powdery mildew, and the hemibiotrophic fungus Diplocarpon rosae, which causes black spot, we analyzed changes in the leaf transcriptome after the inoculation of detached rose leaves with each pathogen. In addition, we analyzed differences in the transcriptomic changes inflicted by both pathogens as a first step to characterize specific infection strategies. Transcriptomic changes were analyzed using next-generation sequencing based on the massive analysis of cDNA ends approach, which was validated using high-throughput qPCR. We identified a large number of differentially regulated genes. A common set of the differentially regulated genes comprised of pathogenesis-related (PR) genes, such as of PR10 homologs, chitinases and defense-related transcription factors, such as various WRKY genes, indicating a conserved but insufficient PTI [pathogen associated molecular pattern (PAMP) triggered immunity] reaction. Surprisingly, most of the differentially regulated genes were specific to the interactions with either P. pannosa or D. rosae. Specific regulation in response to D. rosae was detected for genes from the phenylpropanoid and flavonoid pathways and for individual PR genes, such as paralogs of PR1 and PR5, and other factors of the salicylic acid signaling pathway. Differently, inoculation with P. pannosa leads in addition to the general pathogen response to a downregulation of genes related to photosynthesis and cell wall modification.

Invasive pest species and plant diseases in the south-east of Kazakhstan

     The replenishment of the composition of  invasive pest and diseases occurs due to the introduction of  harmful species with planting material and seeds. For the first time in the territory of the MBG such dangerous pests as Parthenolekanium fletscheriCkll., Coleophora laricella Hb. were identified including 25 species of aphids imported by introduced species that have not previously been reported in the Alma-Ata region. Podosphaera pannosa (Wallr.Fr.) de Bary, Golovinomyces magnicellulataU.Braun, Phragmidium disciflorum (Tode) J.James, Erysiphe ornate var.eurapae (U.Braun), Botrytis paeoniae Oudem are announced to be common plant diseases. According to the assessment of the phytosanitary condition of introduced plants in recent years, an increase in the number of penetrating new species of endangering  insects and diseases is observed. Thus, the number of pests in greenhouses has increased to 13 species from Coccoidea and Aphidinea.     In open ground, the significative of new species is counted to be 9. One type of the diseases  (Uncinulaflexuosa Peck.), was imported with planting material, which had not previously been noted in the conditions of the south-east Kazakhstan. In order to reduce the harmfulness of pests and diseases, such preparations as aktelik, keltan, purified 18 с.e. dicofol, Rum and Haas (USA), omayt, 30% w.p., 57 % c.e. eniroyal, USA have been consumed. These preparation are used with 0.2% conc. against ticks, mealybug, Diaspididae and aphids.The assessment of the harmfulness degree was carried out on a three-point scale.      Key words: invasive pests and plant diseases, control measures.

Engineered nanomaterials inhibit Podosphaera pannosa infection on rose leaves by regulating phytohormones

In the present study, we investigated the antifungal effects of engineered nanomaterials (ENMs) against Podosphaera pannosa (P. pannosa), a fungal pathogen that causes powdery mildew on plants in the rose family. Four commercial ENMs, including multi-wall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), copper oxide (CuO) nanoparticles (NPs) and titanium dioxide (TiO2) NPs, were used to prepare 50 or 200 mg/L NP suspensions in deionized water. Rose leaves in water-agar plates were sprayed by different ENM suspensions mixed with P. pannosa conidia. After a 19-day standard infection test, the growth of P. pannosa on rose leaves was evaluated. All four ENMs inhibited infection by P. pannosa at the concentration 200 mg/L, whereas only CuO NPs decreased fungal growth at 50 mg/L. The phytohormone content of the leaves was measured across all treatments to investigate potential ENMs antifungal mechanisms. The results suggest that ENMs increased plant resistance to fungal infection by altering the content of endogenous hormones, particularly zeatin riboside (ZR). Our study demonstrates that ENMs exhibited distinctly antifungal effects against P. pannosa on roses, and could be utilized as a novel plant protection strategy after a comprehensive assessment of potential environmental risk.

Management of rose powdery mildew (Podosphaera pannosa) through ecofriendly approaches

Powdery mildew is the one of the most severe and devastating disease of roses under protected cultivation. So under this study we have tried different ecofriendly approaches to manage the disease with the use of seven biological control agents (BCAs), nine bio-products and eight plant extracts. Under In vitro studies the highest efficacy was obtained with Bacillus subtilis, neem oil and Allium sativus at their higher concentrations. Among the BCAs the highest disease control was observed in Ampelomyces quisqualis (78.51%), Bacillus subtilis (74.12%), Verticillium lecanii (70.55%) and Trichoderma harzianum (67.33%) under the greenhouse conditions. From the bio-products best disease control was obtained with neem oil (76.18%) at 5% concentration. The best disease control was obtained with plant extract of Allium sativus (71.87%) at 20% concentration.

Podosphaera pannosa causes powdery mildew and rusty spot on peach fruits from Korea

Podosphaera pannosa causes powdery mildew and rusty spot on peach fruits from Korea

Performance of plant defence activators against Podosphaera pannosa causing rose powdery mildew

Different plants defence activators were evaluated against the rose powdery mildew (Podosphaera pannosa) under green house conditions. Plant defence activators were tested at two concentrations i.e. 0.050 and 0.075% before the appearance of disease. The highest disease control of 78.48% was recorded in the plants sprayed with dipotassium orthophosphate followed by salicylic acid (74.62%), β-aminobutyric acid (72.16%), potassium silicate (64.69%) and potassium bicarbonate (66.79%) at concentration of 0.075% in two consecutive years (2015, 2016). The least disease control (54.95%) was observed in treatment with calcium silicate. At lower concentration (0.05%) disease control was comparatively lesser than the higher concentration of the plant defence activators. First spray of the SAR chemical was effective for 21 days and after that the disease appeared.

Evaluation of bupirimate against rose powdery mildew

Bupirimate 25% Emulsifiable concentrate (EC) was evaluated for efficacy on Sphaerotheca pannosa, the causal agent of rose powdery mildew in vivo. In this experiment Bupirimate 25% EC 6 ml/L and 4 ml/L effectively reduced the powdery mildew infection over rest of the treatments and improved the flower yield. Moreover, application of Bupirimate 25% EC at the doses of 2, 4 and 6 ml/L and even at higher dose 8 ml/L did not show any phyto-toxic symptoms on rose plant. Thus, Bupirimate 25% EC may be considered as compared to other fungicides.

A study on JA- and BTH-induced resistance of Rosa rugosa ‘Plena’ to powdery mildew (Sphaerotheca pannosa)

Different concentrations of jasmonic acid (JA) and benzothiadiazole (BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa (Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes (POD, PPO, and PAL) increased significantly. Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R. rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves.

Evaluation of different types of compost tea to control rose powdery mildew (Sphaerotheca pannosa var. rosae)

ABSTRACTPowdery mildew (Sphaerotheca pannosa var. rosae) is an important foliar disease which is found in all rose-producing greenhouses. An experiment was carried out in a commercial greenhouse in Hashtgerd, Iran, in 2014 to investigate whether compost teas can be used to control this disease. Taguchi's design of experiment (Taguchi's DOE) method was used to plan a minimum number of experiments and optimization to control rose powdery mildew. The test included three factors, namely the different types of compost tea (aerated and non-aerated compost tea, aerated and non-aerated vermicompost tea), the dosage (1:8 and 1:16, compost:water), and the number of spray applications (once and twice per week). The experiment was set up as an orthogonal array L8 with three replicates. Based on the experimental results, the optimum treatment combination for controlling rose powdery mildew was found to be aerated compost tea with 1:8 dilution with an application of twice per week.

Detection of pre-symptomatic rose powdery-mildew and gray-mold diseases based on thermal vision

Roses are the most important plants in ornamental horticulture. Roses are susceptible to a number of phytopathogenic diseases. Among the most serious diseases of rose, powdery mildew (Podosphaera pannosa var. rosae) and gray mold (Botrytis cinerea) are widespread which require considerable attention. In this study, the potential of implementing thermal imaging to detect the pre-symptomatic appearance of these fungal diseases was investigated. Effects of powdery mildew and gray mold diseases on rose plants (Rosa hybrida L.) were examined by two experiments conducted in a growth chamber. To classify the healthy and infected plants, feature selection was carried out and the best extracted thermal features with the largest linguistic hedge values were chosen. Two neuro-fuzzy classifiers were trained to distinguish between the healthy and infected plants. Best estimation rates of 92.55% and 92.3% were achieved in training and testing the classifier with 8 clusters in order to identify the leaves infected with powdery mildew. In addition, the best estimation rates of 97.5% and 92.59% were achieved in training and testing the classifier with 4 clusters to identify the gray mold disease on flowers. Performance of the designed neuro-fuzzy classifiers were evaluated with the thermal images captured using an automatic imaging setup. Best correct estimation rates of 69% and 80% were achieved (on the second day post-inoculation) for pre-symptomatic appearance detection of powdery mildew and gray mold diseases, respectively.

Eucalypt powdery mildew caused by Podosphaera pannosa in Brazil

Eucalypt powdery mildew is an important disease in greenhouses and clonal hedges of Eucalyptus spp. in Brazil, which can cause leaf and shoot distortion, shoot discoloration, and growth reduction that results in production losses. Because reliable information regarding the causal agent of the disease is lacking, this study used ITS and 28S rDNA sequencing and morphological analyses to identify the powdery mildew pathogen that occurrs in eucalypt nurseries within different regions in Brazil. Based on the results of morphological characteristics and phylogenetic analyses, the pathogen isolates were identified as Podosphaera pannosa, also known as the rose powdery mildew pathogen. Cross inoculations with pathogen isolates from rose and eucalypt demonstrated that P. pannosa can infect both host species. The ITS sequence-based phylogeny showed that 42 sequences generated in this study were comprised within a single clade containing P. pannosa, which was supported by a posterior probability of 88%. Identical ITS sequences were obtained from all 42 pathogen isolates, which suggests a clonal population.

Assessmens of the Disease Index of Some Peach and Nectarine Cultivars to Powdery Mildew (Sphaerotheca Pannosa) In Albania

Assessmens of the Disease Index of Some Peach and Nectarine Cultivars to Powdery Mildew (Sphaerotheca Pannosa) In Albania

Possibilities of using products containing amino acids in the protection of roses against Podosphaera pannosa and their influence on plant development

The study assessed the influence of the plant growth promoter Agro-Sorb Folium and foliar fertilizers Agro-Sorb L-Amino and Agro- -Sorb Radiculum, used 4 times at 7-day intervals as foliar spray application on roses grown in a greenhouse, on the development of disease symptoms caused by Podosphaera pannosa. Agro-Sorb Folium and Agro-Sorb L-Amino were applied at the concentrations of 0.25, 0.5 and 1%. Their effectiveness ranged from 64 to 98%. An increase in the concentration of the tested products caused an increase in their effectiveness. Agro-Sorb Radiculum used at the concentration of 0.5% showed an effectiveness of about 85%. The fertilizers Agro-Sorb L-amino and Agro-Sorb Radiculum showed an effectiveness of 21.7% and 64%, respectively after a 2-fold watering treatment, and 17% and 10% after a 4-fold applications. All the tested products used as foliar or watering application caused significant stimulation of the growth of rose shrubs. None of the products caused changes in the appearance of roses (phytotoxicity). Oceniano wpływ stymulatora wzrostu roślin Agro-Sorb Folium, nawozów dolistnych Agro-Sorb L-Amino oraz Agro-Sorb Radiculum, stosowanych 4-krotnie co 7 dni do opryskiwania róż uprawianych w szklarni, na rozwój choroby powodowanej przez Podosphaera pannosa. Agro-Sorb Folium oraz Agro-Sorb L-Amino aplikowano w stężeniu 0,25; 0,5 oraz 1%. Ich skuteczność wynosiła od 64 do 98%. Wzrost stężenia badanych środków powodował zwiększenie ich skuteczności. Agro-Sorb Radiculum w stężeniu 0,5%, zastosowany do opryskiwania róż, wykazywał około 85% skuteczności. Nawozy Agro-Sorb L-Amino oraz Agro-Sorb Radiculum po 2-krotnym podlaniu róż wykazywały 21,7% oraz 64% skuteczności, a po 4-krotnym odpowiednio 10% i 17%. Wszystkie badane środki stosowane do opryskiwania lub podlewania powodowały istotną stymulację wzrostu krzewów róż. Żaden z badanych środków nie powodował zmian w wyglądzie róż (fitotoksyczności).

Fertiriego con silicio en variedades de rosa sobre la severidad de mildeo polvoso (Sphaerotheca pannosa var. rosae)

La investigación evaluó el Fertiriego con silicio en la severidad del mildeo polvoso (Sphaerotheca pannosa var. rosae) en tres variedades de rosa bajo invernadero. Se empleó un diseño de parcelas subsubdividas; los tratamientos principales correspondieron a tres dosis de silicio (SiO2) (DS): (DS1=3mgL-1), (DS2=6mgL-1) y (DS3=9mgL-1); los sub-tratamientos a dos tipos de Fertiriego (L): (L1=3 mmdía-1), (L2=5 mmdía-1) y los sub-sub-tratamientos a tres variedades (V): (V1 = Vendela), (V2 = Reed Unique) y (V3 = Miracle). Se presentaron diferencias (p≤0,01) por el efecto de la DS (dosis de silicio), L (láminas de fertiriego) y V (variedades); como también de la interacción DS*L (p≤0,01). Las aplicaciones de DS3 redujeron el porcentaje de severidad del hongo (20%) y las de DS1 fueron menos eficientes (230%). Se obtuvieron menores porcentajes de severidad del hongo con la aplicación de la lámina de agua de fertiriego L1 (130%) y más altos con la L2 (280%). Las variedades V2 y V3 fueron menos afectadas por el hongo (170 y 160%) y la V1 fue más susceptible (320%). La dosis DS3 y la lámina de fertiriego L1 actuaron conjuntamente sobre una menor reducción del grado de severidad del hongo (75%) (p≤0,05). El comportamiento de las variedades Miracle y Reed Unique con una lámina de fertiriego de 3mmdía-1 y dosis de 9mgL-1 de Silicio, podrían ser claves para la disminución de la severidad de Sphaerotheca pannosa var. rosae en zonas productoras de flores de Colombia.

Biological control of rose powdery mildew (Podosphaera pannosa (Wallr.: Fr.) de Bary

Powdery mildew, caused by Podosphaera pannosa (Wallr.: Fr.) de Bary (Syn. Sphaerotheca pannosa var rosae (Wallr.: Ex Fr.) Lev.), is one of the most important fungal diseases in roses. These are obligate parasites and considered as one of the most distributed and destructive groups of plant pathogens. The symptoms appear on leaves, shoots, buds, thorns, peduncles and flowers as powdery, whitish growth (mycelium, conidiophores and spores) of the mildew fungus. Plants can be severely stunted if they are heavily infected early in the growing season. The disease has been managed mainly by chemical fungicides but increasing public concern over the use of fungicides has made the development of biological control for powdery mildew highly desirable. Recent reports have highlighted the potential of biological control as an alternative strategy for disease management. Several biological control methods such as use of microbial antagonists (fungi, bacterial, yeast and yeast like organisms), botanicals and bioproducts have been found effective against rose powdery mildew fungi. The main objective of this review paper is to summarize the data on the microbial antagonists, bioproducts (anhydrous milk products, oils and compost extracts) and botanicals which have been reported effective for the better management of this plant pathogen.

Quantitative trait loci (QTLs) identification and the transmission of resistance to powdery mildew in apricot

Powdery mildew, caused by Sphaerotheca pannosa var. Persicae, is one of the most important diseases in apricot production areas around the world. The transmission of resistance to powdery mildew and the identification of related quantitative trait loci (QTLs) were analysed during 3 years in two F1 apricot progenies derived from the crosses ‘Bergeron’ × ‘Currot’ (B × C) and ‘Goldrich’ × ‘Currot’ (G × C). Field evaluation showed the great variability and segregation in each apricot population in terms of powdery mildew symptoms, demonstrating the polygenic nature and quantitative inheritance of this trait. In accordance with this polygenic nature, several related QTLs were detected using the Kruskal–Wallis non-parametric test, with two main genomic regions are involved in powdery mildew resistance in apricot. Two identified QTLs were mapped in the genetic linkage groups 2 (LG2) and 3 (LG3). In addition, in LG2 we can highlight the single nucleotide polymorphism (SNP) S2_18992724, which shows a strong influence in the presence-absence of disease. Finally, other linkage groups such as LG1, LG5 and LG6 were also related to different levels of expression of powdery mildew symptoms, but their influence appears to be less significant.

Occurrence of powdery mildew caused by Podosphaera pannosa on lemon eucalyptus

SummaryIn 2014, powdery mildew was observed on pot‐grown lemon eucalyptus (Corymbia citriodora, Myrtaceae) in Korea. Based on morphological data and phylogenetic analysis of anamorph isolates, this fungus was identified as Podosphaera pannosa. This is the first report of powdery mildew caused by P. pannosa on lemon eucalyptus. Our results, which include a detailed morphological description and molecular data analysis, support previous records of P. pannosa on Eucalyptus spp. and thus on taxa outside the Rosaceae.

Antifungal Activity of two Botanical Extracts on Rose Crop (Rosa L. Sp.), Against Sphaerotheca Pannosa Var. Rosae

Abstract Powdery mildew (PM) caused by the fungus Sphaerotheca pannosa var. rosae is the most widespread and economically important disease affecting the commercial sector of the rose production in Ecuador. Its incidence is influenced by the environmental agents and is affecting the aerial parts of the rose: stems, leaves and bottoms. The present study investigates aqueous and alcoholic botanical extracts of Ocotea quixos and Piper carpunya as alternatives to agrochemicals. For this reason, an in vitro evaluation has been developed for the antifungal activity of the leaf extracts of these two plants. The alcoholic extracts of P. carpunya and O. quixos and the aqueous ones of O. quixos, demonstrated the most efficient biological control against the fungus S. pannosa. The second step of the experiment consisted of applying in an in vivo experiment the efficient plant extracts resulted from the first in vitro tests. The application consisted in three doses for eight days during two cycles of rose cultures. It was evaluated the control level during four periods of time (15, 30, 45 and 60 days), based on the level of visual scale of damage on the leaves, stems and buds, noted with values from 1 to 5. The results demonstrated the efficiency of the extracts to prevent and control the fungus infection in rose culture and a further use as part of the biological control.

English

Sodium silicate was dissolved in water in either a monomer form or polymer form; the effects of both forms of sodium silicate aqueous solution on rose powdery mildew and root rot diseases of miniature rose were examined. Both forms of sodium silicate aqueous solution were applied to the roots of the miniature rose. Potassium silicate aqueous solution was used as a control and was compared to the effect of sodium silicate aqueous solution. The polymer sodium silicate aqueous solution was the most effective treatment against both powdery mildew and root rot diseases. Moreover, no inhibition effects of silicate solutions were observed in vitro on Pythium helicoides, the causal pathogen of rose root rot disease. The silicon contents in the roots of the miniature rose treated with polymer sodium silicate were significantly greater than that in plants treated with monomer sodium silicate. In conclusion, the suppressive effects of sodium silicate in the polymer form were confirmed against powdery mildew and root rot diseases of the miniature rose. Key words: Podosphaera pannosa, Pythium helicoides, miniature rose, polymer and monomer sodium silicate.