A Foliar Blight and Tuber Rot of Potato Caused by Phytophthora nicotianae: New Occurrences and Characterization of Isolates

Phytophthora spp. are pathogenic to many plant species worldwide, and late blight, caused by Phytophthora infestans, and pink rot, caused by P. erythroseptica, are two important diseases of potato. Another Phytophthora sp., P. nicotianae, was recovered from pink-rot-symptomatic tubers collected from commercial fields in Nebraska, Florida, and Missouri in 2005, 2006, and 2007, respectively. P. nicotianae also was recovered from foliage obtained from commercial potato fields in Nebraska and Texas exhibiting symptoms very similar to those of late blight. Isolates of P. cactorum also were recovered from foliar infections in a commercial potato field in Minnesota in 2005. Natural infection of potato foliage by P. cactorum and infection of wounded potato tuber tissue via inoculation with zoospores of P. capsici are reported here for the first time. Isolates of P. nicotianae, regardless of origin, were primarily of the A1 mating type. All isolates of P. nicotianae and P. cactorum were sensitive to the fungicide mefenoxam. Optimum growth of P. nicotianae, P. erythroseptica, and P. cactorum in vitro occurred at 25°C; however, only P. nicotianae sustained growth at 35°C. Regardless of the tissue of origin, all isolates of P. nicotianae and P. cactorum were capable of infecting potato tubers and leaves. However, isolates of P. nicotianae were less aggressive than P. erythroseptica isolates only when tubers were not wounded prior to inoculation. Pink rot incidence varied significantly among potato cultivars following inoculation of nonwounded tubers with zoospores of P. nicotianae, ranging from 51% in Red Norland to 19% in Atlantic. Phytophthora spp. also differed significantly in their ability to infect potato leaves. Highest infection frequencies were obtained with P. infestans and levels of infection varied significantly among P. nicotianae isolates. The rate of foliar lesion expansion was similar among isolates of P. nicotianae and P. infestans. Whereas P. infestans infections yielded profuse sporulation, no sporulation was observed with foliar infections of P. nicotianae.

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Efeito do lodo de esgoto na indução de supressividade in vitro a Phytophthora nicotianae

Fitopatologia Brasileira ◽

10.1590/s0100-41582003000100010 ◽

2003 ◽

Vol 28 (1) ◽

pp. 67-75 ◽

Cited By ~ 2

Author(s):

Carolina Leoni ◽

Raquel Ghini

Keyword(s):

Triticum Aestivum ◽

Medicago Sativa ◽

Phytophthora Nicotianae ◽

Phytophthora Spp ◽

Trichoderma Sp ◽

Aspergillus Sp

Uma alternativa de manejo das doenças causadas por Phytophthora spp. é o uso de matéria orgânica. No presente trabalho foi avaliada a potencialidade do lodo de esgoto na indução de supressividade in vitro a P. nicotianae. O efeito do lodo de esgoto incorporado ao solo na sobrevivência de P. nicotianae foi avaliado mediante um experimento fatorial com dois fatores: doses de lodo de esgoto (0, 10, 20 e 40% p/p) e concentrações de inóculo [0, 10 ou 20 g de grãos de trigo (Triticum aestivum) colonizados kg-1]. Aos 21 dias, quando aumentaram as doses de lodo de esgoto, a sobrevivência de P. nicotianae e os pHs das misturas diminuíram, e as condutividades elétricas (CE) aumentaram. As correlações entre a CE e a sobrevivência do patógeno foram negativas e significativas (P>0,05). Para estudar o efeito dos compostos químicos envolvidos na supressividade, foram obtidos extratos em água, H2SO4 2N e KOH 0,4N de misturas de areia – lodo de esgoto (20% p/p), e foram acrescentados ao meio de cultura e seu efeito avaliado no crescimento das colônias de P. nicotianae. O extrato ácido (H2SO4 2N) do tratamento com 20% de lodo de esgoto inibiu significativamente (P>0,05) o crescimento da colônia do patógeno. O efeito biológico foi estudado mediante isolamento de microrganismos em meio de cultura e seleção por antagonismo. No bioensaio com plântulas de alfafa (Medicago sativa) destacaram-se os isolados F9.1 (Aspergillus sp.) e A12.1 (actinomiceto, não identificado); e no teste de culturas pareadas destacou-se um Trichoderma sp. e dois actinomicetos por antibiose, e um Trichoderma sp. e três Aspergillus sp. por hiperparasitismo.

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Etiology of a Tuber Rot and Foliar Blight of Potato Caused by Phytophthora nicotianae

Plant Disease ◽

10.1094/pdis-05-14-0519-re ◽

2015 ◽

Vol 99 (4) ◽

pp. 474-481 ◽

Cited By ~ 1

Author(s):

Raymond J. Taylor ◽

Julie S. Pasche ◽

Neil C. Gudmestad

Keyword(s):

The United States ◽

Phytophthora Nicotianae ◽

Inoculum Concentration ◽

Foliar Blight ◽

Progress Curve ◽

Water Splash ◽

Soil Infestation ◽

Potato Foliage ◽

Progeny Tuber ◽

Tuber Rot

Although Phytophthora nicotianae is not normally considered to be an important pathogen of potato (Solanum tuberosum), intermittent outbreaks of a foliar blight and tuber rot have been reported in the United States over the past 75 years. Due to the sporadic nature of these reports, little is known about the etiology of the disease in potato. However, foliar disease and tuber rots caused by this pathogen are usually centered near areas of standing water in the field and along pivot tracks. Moreover, soil particles adhering to the foliage of infected potato plants suggest that water splash is involved in P. nicotianae dissemination and infection. Soil infestation and water splash dissemination studies were conducted under greenhouse conditions to examine the role that zoospores of P. nicotianae may play in disease on potato. In the soil infestation study, inoculum of P. nicotianae was added to soil at four rates (0.0, 1.0 × 103, 5.0 × 103, and 4.0 × 104 zoospores/ml) and three timings (at planting and 7 and 14 days after planting). Direct infection of aboveground plant tissues was achieved via splash dissemination of inoculum onto potato foliage. All soil infestations significantly reduced emergence, with the exception of the 1.0 × 103 zoospores/ml treatment, and no plants emerged from soil infested with 4.0 ×104 zoospores/ml. Significant reductions in stem number were observed with infestations of 1.0 × 103 and 5.0 × 103 zoospores/ml at planting and 5.0 × 103 zoospores/ml at 7 days after planting. Progeny tuber infections were confirmed with infestations at 1.0 × 103 zoospores/ml at planting and 7 days after planting. Lesions developed on leaflets, petioles, leaf axils, and stems in all water splash dissemination treatments within 3 days of inoculation, significant differences in the lesion number were observed, and disease severity generally was proportional to inoculum concentration. Relative area under the disease progress curve of the 5.0 × 103 and 4.0 × 104 zoospores/ml splash dissemination treatments was significantly greater than the 0.0 zoospore and 1.0 × 103 zoospores/ml treatments. Progeny tuber infections were observed with all water splash dissemination treatments but infection rates did not differ significantly among treatments. These studies confirm the hypothesis that water splash dissemination of P. nicotianae inoculum is a likely means by which infections of this pathogen are initiated in potato.

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Phytophthora nicotianae Infection of Citrus Leaves and Host Defense Activation Compared to Root Infection

Phytopathology ◽

10.1094/phyto-09-19-0343-r ◽

2020 ◽

Vol 110 (8) ◽

pp. 1437-1448

Author(s):

Jian Wu ◽

Utpal Handique ◽

James Graham ◽

Evan Johnson

Keyword(s):

Phytophthora Nicotianae ◽

Hormonal Responses ◽

Host Pathogen Interaction ◽

Phytophthora Spp ◽

Molecular Events ◽

Pathogenesis Related ◽

Root Responses ◽

Citrus Leaves ◽

Genetic Responses ◽

First Time

Currently, little is known about the host pathogen interaction between Phytophthora spp. and citrus roots versus leaves. Therefore, we compared the molecular events occurring in citrus roots and leaves after zoospore inoculation with Phytophthora nicotianae. We analyzed the physical characteristics and genetic responses to P. nicotianae infection of leaves and roots for susceptible and tolerant citrus rootstocks to examine the potential for leaves to model root responses to P. nicotianae infection. Leaves responded faster and stronger to P. nicotianae infection than roots, and leaves showed greater differential response than roots. In addition to differences in hormonal responses, sugar, phospholipase D (PLD), and phospholipase A (PLA) involvement in the interaction between citrus and P. nicotianae was identified. This work, for the first time, creates a solid P. nicotianae zoospore infection protocol, reports P. nicotianae infection on citrus leaves through stomata, and provides evidence that different host organs respond to the pathogen differentially in timing and magnitude. This work identifies the hormones, sugars, pathogenesis-related genes, PLDs, and PLAs that are involved in the molecular events occurring in citrus under infection of P. nicotianae zoospore, and advances our understanding of the mechanisms underlying the interaction.

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Phytophthora spp.: Economic Plant Threats in Egypt

10.5772/intechopen.101115 ◽

2021 ◽

Author(s):

Waleed Mohamed Hussain Abdulkhair

Keyword(s):

Late Blight ◽

Integrated Management ◽

Potato Crop ◽

Control Plant ◽

Phytophthora Nicotianae ◽

Management Approach ◽

Economic Plant ◽

Phytophthora Spp ◽

Rot Disease ◽

Blight Disease

The potato crop is exposed to infection with many fungal diseases including late blight, caused by Phytophthora infestans. The control of late blight disease requires an integrated management approach represented in cultivation control, plant resistance, and fungicide control. The citrus plants are infected by Phytophthora nicotianae that is causing root rot disease in Egypt. Three species of Phytophthora responsible for infection of citrus plants; P. nicotianae, P. citrophthora, and P. palmivora. Other pathogens associate P. nicotianae and form complexes or coinfection that release different diseases for citrus plants such as gummosis, Phytophthora–Diaprepes complex (PDC), and Huanglongbing syndrome (HLBS).

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Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

Plant Tissue Culture and Biotechnology ◽

10.3329/ptcb.v19i1.4990 ◽

1970 ◽

Vol 19 (1) ◽

pp. 89-99

Author(s):

K. Choudhary ◽

M. Singh ◽

M. S. Rathore ◽

N. S. Shekhawat

Keyword(s):

Somatic Embryogenesis ◽

Growth Regulators ◽

Somatic Embryos ◽

Basal Medium ◽

Long Term Study ◽

Continuous Application ◽

First Time ◽

Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l of 2,4-D and 0.5 mg/l of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

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Dwindling status of Epimedium Elatum (Morren & Decne) and its geographical distribution in Kashmir Himalaya, India

Current Botany ◽

10.25081/cb.2018.v9.20180106 ◽

2018 ◽

pp. 47-52

Keyword(s):

Medicinal Plant ◽

Biological Activities ◽

Conservation Status ◽

Natural Populations ◽

Culture Techniques ◽

Kashmir Himalayas ◽

Near Future ◽

First Time ◽

Tissue Culture Techniques

Epimedium elatum (Morren & Decne) of family Berberidaceace is a rare perennial medicinal plant, endemic to high altitude forests of Northwestern Himalayas in India. Ethnobotanically, it has been used as an ingredient for treatment of bone-joint disorders, impotence and kidney disorders in Kashmir Himalayas. Phytochemically, it is rich in Epimedin ABC and Icariin; all of these have been demonstrated to possess remarkable biological activities like PDE-5 inhibition (treatment of erectile dysfunction), anticancer, antiosteoporosis antioxidant and antiviral properties. The present investigation reports its traditional usage, comprehensive distribution and conservation status from twenty ecogeographical regions in Kashmir Himalayas, India. The species was reported from Gurez valley for the first time. Numerous threats like excessive grazing, deforestration, habitat fragmentation, tourism encroachment, landslides and excessive exploitation have decreased its natural populations in most of the surveyed habitats. Consequently, its existence may become threatened in near future if timely conservation steps are not taken immediately by concerned stakeholders involved in medicinal plant research. Moreover, use of plant tissue culture techniques is recommended for development of its in vitro propagation protocols. Therefore, introduction of this medicinal plant in botanical gardens, protected sites and development of monitoring programmes are needed for its immediate conservation in Northwestern Himalayas, India.

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Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

10.26434/chemrxiv.7957544 ◽

2019 ◽

Cited By ~ 1

Author(s):

Daria Monaldi ◽

Dante Rotili ◽

Julien Lancelot ◽

Martin Marek ◽

Nathalie Wössner ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Human Cancer ◽

Egg Laying ◽

Human Cancer Cells ◽

Parasite Survival ◽

Survival And Reproduction ◽

Emergence Of Resistance ◽

First Time ◽

Parasitic Life Cycle

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

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α-Glucosidase Inhibition and Docking Studies of 5-Deoxyflavonols and Dihydroflavonols Isolated from Abutilon pakistanicum

Current Organic Chemistry ◽

10.2174/1385272823666191001224741 ◽

2019 ◽

Vol 23 (17) ◽

pp. 1857-1866

Author(s):

Munawar Hussain ◽

Zaheer Ahmed ◽

Shamsun N. Khan ◽

Syed A. A. Shah ◽

Rizwana Razi ◽

...

Keyword(s):

Methanolic Extract ◽

Docking Studies ◽

Hydroxyl Group ◽

Coumaric Acid ◽

In Vitro Activity ◽

Aerial Parts ◽

First Time ◽

Acid Esters ◽

Phenol Moiety

Three new 5-deoxyflavonoid and dihydroflavonoids 2, 3 and 4 have been isolated from the methanolic extract of Abutioln pakistanicum aerial parts, for which structures were elucidated explicitly by extensive MS- and NMR-experiments. In addition to these, 3,7,4′-trihydroxy-3′-methoxy flavonol (1) is reported for the first time from Abutioln pakistanicum. Compound 2 and 4 are p-coumaric acid esters while compounds 2–4 exhibited α-glucosidase inhibitory activity. Docking studies indicated that the ability of flavonoids 2, 3 and 4 to form multiple hydrogen bonds with catalytically important residues is decisive hence is responsible for the inhibition activity. The docking results signified the observed in-vitro activity quite well which is in accordance with previously obtained conclusion that phenol moiety and hydroxyl group are critical for the inhibition of α-glucosidase enzyme.

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Antimutagenic, Antiproliferative and Antioxidant Properties of Sea Grape Leaf Extract Fractions (Coccoloba uvifera L.)

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520621999210104201242 ◽

2021 ◽

Vol 21 ◽

Author(s):

Jorge A. Ramos-Hernández ◽

Montserrat Calderón-Santoyo ◽

Armando Burgos-Hernández ◽

Joel S. García- Romo ◽

Arturo Navarro-Ocaña ◽

...

Keyword(s):

Antioxidant Properties ◽

In Vitro Tests ◽

Antimutagenic Activity ◽

Hexane Extraction ◽

Biological Potential ◽

Hct 116 ◽

Pharmaceutical Industries ◽

Grape Leaf ◽

First Time

Background: Cancer is a disease characterized by the invasion and uncontrolled growth of cells. One of the best ways to minimize the harmful effects of mutagens is through the use of natural antimutagens. In this regard, the search for new antimutagens that act in the chemoprevention could represent a promising field in this area. Objective: In this study biological potential of 11 fractions from Coccoloba uvifera L. leaf hexane extract was evaluated by several in vitro tests. Methods: Leaves were lyophilized and hexane extraction was performed. The extract was fractionated by column chromatography with hexane, ethyl acetate, and methanol. The antimutagenic (Ames test), antiproliferative (MTT test), and antioxidant capacity (DPPH, ABTS, and ferrous ion chelation) of the fractions were evaluated. Results: Fractions 4, 6, 8, and 9 have antimutagenic activity (against sodium azide in strain TA100), fraction 11 showed antiproliferative capacity (IC50 of 24 ± 9 μg/mL in cells of HCT 116). The fractions with the highest activity were analyzed by HPLC-MS and lupeol, acacetin, and β-sitosterol were identified. Conclusion: This study demonstrates, for the first time, the bioactivity of C. uvifera leaf as a new source of high biological value compounds (HBVC), which can be of interest to the food and pharmaceutical industries.

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Protection of Citrus Rootstocks Against Phytophthora spp. with a Hypovirulent Isolate of Phytophthora nicotianae

Phytopathology ◽

10.1094/phyto-97-8-0958 ◽

2007 ◽

Vol 97 (8) ◽

pp. 958-963 ◽

Cited By ~ 7

Author(s):

G. C. Colburn ◽

J. H. Graham

Keyword(s):

Poncirus Trifoliata ◽

Phytophthora Nicotianae ◽

Root Weight ◽

Post Inoculation ◽

Phytophthora Root Rot ◽

Phytophthora Spp ◽

Naturally Occurring ◽

Fibrous Roots ◽

Cleopatra Mandarin ◽

Swingle Citrumelo

Phytophthora root rot of citrus in Florida is caused by Phytophthora nicotianae and P. palmivora. A naturally occurring isolate of P. nicotianae (Pn117) was characterized as hypovirulent on citrus roots. Pn117 infected and colonized fibrous roots, but caused significantly less disease than the virulent isolates P. nicotianae Pn198 and P. palmivora Pp99. Coincident inoculation of rootstock seedlings of Cleopatra mandarin (Citrus reticulata) or Swingle citrumelo (C. paradisi × Poncirus trifoliata) with the hypovirulent Pn117 and the virulent isolates Pn198 and Pp99 did not reduce the severity of disease caused by the virulent Phytophthora spp. When either rootstock was inoculated with the hypovirulent Pn117 for 3 days prior to inoculation with virulent isolates, preinoculated seedlings had significantly less disease and greater root weight compared with seedlings inoculated with the virulent isolates alone. Recovery of the different colony types of Phytophthora spp. from roots of sweet orange (C. sinensis) or Swingle citrumelo was evaluated on semiselective medium after sequential inoculations with the hypovirulent Pn117 and virulent Pp99. Pn117 was isolated from roots at the same level as the Pp99 at 3 days post inoculation. Preinoculation of Pn117 for 3 days followed by inoculation with Pp99 resulted in greater recovery of the hypovirulent isolate and lower recovery of the virulent compared with coincident inoculation.

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