scholarly journals Genetic and Pathogenic Variation in Phytophthora cactorum Affecting Fruit and Nut Crops in California

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 161-169 ◽  
Author(s):  
R. G. Bhat ◽  
P. M. Colowit ◽  
T. H. Tai ◽  
M. K. Aradhya ◽  
G. T. Browne
Keyword(s):  
Genomic Dna ◽  
Significant Proportion ◽  
Aflp Analysis ◽  
Phytophthora Cactorum ◽  
Aflp Data ◽  
Minor Variation ◽  
Phytophthora Spp ◽  
Pathogenic Variation ◽  
Plant Nursery ◽  
Management Approaches

Isolates of Phytophthora cactorum and 15 other species of Phytophthora were characterized according to their genomic DNA, pathogenicity, and sensitivity to mefenoxam. Amplified fragment length polymorphism (AFLP) analysis was completed for 132 isolates of P. cactorum (30 from almond, 86 from strawberry, 5 from walnut, and 11 from other hosts) and 22 isolates of 15 other Phytophthora spp. from various hosts. All 16 Phytophthora spp. were distinguishable by unique AFLP banding patterns. Cluster analysis of the AFLP data revealed high coefficients of genetic similarity (>0.9) among all California isolates of P. cactorum. Analysis of molecular variance indicated that, among all 132 isolates of P. cactorum, 30.8 and 24.5% of the AFLP variation was associated with hosts and geographical sources of isolates, respectively, whereas 15.0% of the variation was associated with isolate niche (i.e., an aerial plant part, portion of the root system, or soil). Among the 86 isolates of P. cactorum from strawberry, characterization by source in the production system (i.e., fruiting field or plant nursery) did not account for a significant proportion of the variation (0.6%, P = 0.204). In pathogenicity tests on strawberry plants (cv. Diamante) in a greenhouse, isolates of P. cactorum from hosts other than strawberry and an isolate from a strawberry fruit caused only negligible amounts of disease, but isolates from strawberry root systems were highly aggressive. On excised shoot segments of almond (cv. Drake), all isolates of P. cactorum originally from almond were pathogenic, and 8 of 17 isolates of the pathogen from other hosts caused significantly less disease than the almond isolates. All 132 isolates of P. cactorum were sensitive to mefenoxam at 1 ppm. Populations of P. cactorum in California apparently are mefenoxam sensitive and exhibit host specificity with relatively minor variation in genomic DNA. The genetic variation observed in P. cactorum included significant geographical and host origin components, which has implications for disease management approaches.

scholarly journals Morphological and molecular identification of phytophthora species from maple trees in Serbia

Genetika ◽  
2014 ◽  
Vol 46 (2) ◽  
pp. 353-368 ◽  
Author(s):  
Ivan Milenkovic ◽  
Justyna Nowakowska ◽  
Tomasz Oszako ◽  
Katarina Mladenovic ◽  
Aleksandar Lucic ◽  
...  
Keyword(s):  
Molecular Identification ◽  
Genomic Dna ◽  
Its Region ◽  
Phytophthora Species ◽  
Morphological Identification ◽  
First Report ◽  
Phytophthora Spp ◽  
Isolated Species

The paper presents the results of the study performed with aims to determine the presence and diversity of Phytophthora species on maple trees in Serbia. Due to high aggressiveness and their multicyclic nature, presence of these pathogens is posing significant threat to forestry and biodiversity. In total, 29 samples of water, soil and tissues were taken from 10 different localities, and six different maple hosts were tested. After the isolation tests, 17 samples from five different maple hosts were positive for the presence of Phytophthora spp., and 31 isolates were obtained. After the detailed morphological and physiological classification, four distinct groups of isolates were separated. DNA was extracted from selected representative isolates and molecular identification with sequencing of ITS region was performed. Used ITS4 and ITS6 primers successfully amplified the genomic DNA of chosen isolates and morphological identification of obtained isolates was confirmed after the sequencing. Four different Phytophthora species were detected, including P. cactorum, P. gonapodyides, P. plurivora and P. lacustris. The most common isolated species was homothallic, and with very variable and semipapillate sporangia, P. plurivora with 22 obtained isolates. This is the first report of P. plurivora and P. gonapodyides on A. campestre, P. plurivora and P. lacustris on Acer heldreichii and first report of P. lacustris on A. pseudoplatanus and A. tataricum in Serbia.

scholarly journals Reciprocal hybridization between diploid Ficaria calthifolia and tetraploid Ficaria verna subsp. verna: evidence from experimental crossing, genome size and molecular markers

2019 ◽  
Vol 189 (3) ◽  
pp. 293-310 ◽  
Author(s):  
Ondřej Popelka ◽  
Michal Sochor ◽  
Martin Duchoslav
Keyword(s):  
Genome Size ◽  
Morphological Variability ◽  
Plastid Dna ◽  
Genotypic Diversity ◽  
Hybrid Origin ◽  
Aflp Analysis ◽  
Sympatric Populations ◽  
Aflp Data ◽  
Evolutionary Forces ◽  
Genetic Clusters

Abstract Ficaria is a taxonomically intriguing polyploid complex with high morphological variability. Both hybridization and polyploidization have been suggested as the main evolutionary forces behind the high morphological variability in this genus; however, detailed studies are lacking. In Central Europe, two Ficaria taxa (diploid F. calthifolia and tetraploid F. verna subsp. verna) occasionally co-occur in local sympatry, which might result in hybridization. We investigated sympatric populations of the two Ficaria taxa using flow cytometry, chromosome counts, AFLP analysis and plastid DNA sequencing; we also performed experimental homoploid and heteroploid crosses to determine the frequency and direction of hybrid triploid formation, an alternative route of triploid origin (autopolyploidy) and the possibility of a one-step neoallotetraploid origin. Sympatric populations were composed of three genetic clusters corresponding to diploid F. calthifolia (2n = 16), tetraploid F. verna subsp. verna (2n = 32) and triploid plants (2n = 24). The holoploid genome size and AFLP data suggest a hybrid origin of the triploids, thereby making their formation via autopolyploidization in F. calthifolia unlikely. The triploid populations are monoclonal and of independent origin. In contrast, the parental populations exhibit high genotypic diversity and frequent sexual reproduction, including those of predominantly asexual F. verna subsp. verna. Experimental crossing confirmed that both parental taxa produce fertile seeds via a sexual pathway, but not by apomixis, and that both serve as pollen acceptors in heteroploid crosses, which is consistent with the plastid sequencing. However, hybridization is asymmetric, with maternal-excess crosses being significantly more successful. No signs of neoautotetraploidization or neoallotetraploidization were detected. In summary, recent gene flow between the studied Ficaria taxa is either limited or absent.

Genetic Variability in the Potato Pathogen Colletotrichum coccodes as Determined by Amplified Fragment Length Polymorphism and Vegetative Compatibility Group Analyses

2006 ◽  
Vol 96 (10) ◽  
pp. 1097-1107 ◽  
Author(s):  
Larry J. Heilmann ◽  
Nadav Nitzan ◽  
Dennis A. Johnson ◽  
Julie S. Pasche ◽  
Curt Doetkott ◽  
...  
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Vegetative Compatibility ◽  
Colletotrichum Coccodes ◽  
Aflp Analysis ◽  
Aflp Data ◽  
Bootstrap Analysis ◽  
Nit Mutants

Amplified fragment length polymorphism (AFLP) using three primer sets was used to characterize 211 Colletotrichum coccodes isolates from North America, 112 of which were assigned to six vegetative compatibility groups (VCGs) using nitrate nonutilizing (nit) mutants. These isolates clustered into five corresponding groups by unweighted pairgroup method with arithmetic means-based cluster analysis of AFLP banding patterns. Isolates of C. coccodes belonging to NA-VCG1 and NA-VCG3 were closely related, as were isolates belonging to NA-VCG2 and NA-VCG5. Based on bootstrap analysis of AFLP data, the two isolates originally assigned to NA-VCG4 clustered with isolates belonging to NA-VCG2 and NA-VCG5. C. coccodes isolates that clustered with two isolates belonging to NA-VCG6 were the most diverged from other groups, including seven isolates collected from hosts other than potato. As opposed to the bootstrap analysis, a quadratic discriminant analysis (QDA) of AFLP data correctly categorized the two isolates of NA-VCG4. Furthermore, in isolates where VCG determinations had been made, this model correctly classified isolates of all VCGs. QDA classifications were identical to those made by the bootstrap analysis, with the exception of VCG4. Overall, classifications made by the QDA model were strongly correlated (r = 0.970, P < 0.001) to the VCGs assigned by traditional methods. All 99 C. coccodes isolates evaluated only by AFLP also were subjected to QDA, leading to the assignment of a presumptive VCG for each isolate. No isolates of VCG4 or VCG6 were identified by QDA within this population. Symptoms of black dot developed in plants inoculated with isolates collected from both potato and non-potato hosts. However, total yield was not significantly reduced by infection with non-potato isolates. The lack of any additional groups identified by AFLP analysis may be an indicator of a limited level of genetic variation among North American C. coccodes isolates. AFLP is a much more efficient technique for subspecific characterization in C. coccodes than VCG analysis utilizing nit mutants and will provide an effective means by which the population biology of this pathogen can be further investigated worldwide.

Treatment of Pediatric OCD

2017 ◽  
Author(s):  
S. Evelyn Stewart ◽  
Clare Bleakley
Keyword(s):  
Clinical Decision Making ◽  
Significant Proportion ◽  
Clinical Decision ◽  
Developmental Trajectory ◽  
First Line ◽  
Pediatric Ocd ◽  
Response Predictors ◽  
Augmentation Strategies ◽  
Negative Impacts ◽  
Management Approaches

Appropriate OCD treatment has the potential to reverse negative impacts on the developmental trajectory of youth with this disease. First-line treatments for pediatric OCD have been well established, including cognitive behavior therapy (CBT), serotonin reuptake inhibitors (SRI), and the combination thereof. However, a significant proportion of OCD-affected youth do not achieve response or remission following initial treatment, and access to OCD-focused CBT treatment is often limited. Knowledge of CBT and SRI response predictors, mechanisms of action, and augmentation strategies for pediatric OCD should be exploited to guide individual clinical decision making. Further investigation is required to identify specific management approaches in treatment-resistant cases and putative OCD subtypes. This chapter summarizes proven first-line pharmacological and psychological treatments, discusses potential augmentation strategies, and suggests practical management tips for use in pediatric OCD.

Temporal patterns of airborne Phytophthora spp. in a woody plant nursery area detected using real-time PCR

Aerobiologia ◽  
2018 ◽  
Vol 35 (2) ◽  
pp. 201-214 ◽  
Author(s):  
Duccio Migliorini ◽  
Luisa Ghelardini ◽  
Nicola Luchi ◽  
Paolo Capretti ◽  
Marzia Onorari ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Woody Plant ◽  
Temporal Patterns ◽  
Nursery Area ◽  
Phytophthora Spp ◽  
Plant Nursery

Preliminary study on geographical distribution and evolutionary relationships between cultivated and wild adzuki bean (Vigna angularis var. angularis and var. nipponensis) by AFLP analysis

2003 ◽  
Vol 1 (2-3) ◽  
pp. 175-183 ◽  
Author(s):  
Zong Xu-xiao ◽  
Duncan Vaughan ◽  
Norihiko Tomooka ◽  
Akito Kaga ◽  
Wang Xin-wang ◽  
...  
Keyword(s):  
Geographical Distribution ◽  
Nucleotide Diversity ◽  
Evolutionary Relationships ◽  
Aflp Analysis ◽  
Adzuki Bean ◽  
Asian Countries ◽  
Vigna Angularis ◽  
Aflp Data ◽  
Preliminary Study

AbstractA set of 146 representative adzuki (Vigna angularis var. angularis and var. nipponensis) germplasm from six Asian countries with a tradition of adzuki bean production, together with an outgroup standard rice bean (Vigna umbellata), were analysed by amplified fragment length polymorphism (AFLP) methodology using 12 informative primer pairs. A total of 313 unambiguous polymorphic bands were created. According to the dendrogram, using cluster analysis based on AFLP banding, 143 of the accessions were distinct and revealed enough genetic diversity for identification and classification of accessions within Vigna angularis. A neighbour-joining tree was generated using the newly developed Innan's nucleotide diversity estimate from the AFLP data. From analysis, seven distinct evolutionary groups, named ‘Chinese cultivated’, ‘Japanese cultivated’, ‘Japanese complex-Korean cultivated’, ‘Chinese wild’, ‘China Taiwan wild’, ‘Nepal- Bhutan cultivated’ and ‘Himalayan wild’, were detected. Nucleotide diversity with geographical distribution of each group is discussed, regarding the evolutionary relationships between wild and cultivated adzuki beans. The preliminary results indicated that cultivated adzuki beans have been domesticated from at least four progenitors with at least three geographical origins.

scholarly journals Effects of Phosphonate and Mefenoxam Treatments on Development of Perennial Cankers Caused by Two Phytophthora spp. on Almond

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 241-249 ◽  
Author(s):  
G. T. Browne ◽  
M. A. Viveros
Keyword(s):  
Topical Treatment ◽  
Prunus Dulcis ◽  
San Joaquin Valley ◽  
Disease Suppression ◽  
Phytophthora Cactorum ◽  
Time Intervals ◽  
Chemical Treatments ◽  
Foliar Sprays ◽  
Phytophthora Spp

Orchard experiments were conducted to evaluate chemical treatments for management of perennial cankers caused by Phytophthora cactorum and P. citricola on almond (Prunus dulcis) in the San Joaquin Valley of California. Single preventive foliar sprays with phosphonate were tested by wounding and inoculating tree trunks and branches with either pathogen at time intervals from 15 days to 5 months after spraying. One to 3 months after inoculation, resulting cankers were measured. Preventive foliar sprays with phosphonate in the fall or spring suppressed development of cankers for up to 5 months after treatment; mean canker lengths on the trees sprayed with phosphonate before inoculation were 22 to 98% smaller than those on trees that received no phosphonate. In subsequent tests, preventive chemigation with phosphonate in spring or summer also inhibited canker expansion. A curative topical treatment with either fosetyl-Al or mefenoxam on cankers caused by P. cactorum or P. citricola reduced canker expansion by 36 to 88%. Neither preventive nor therapeutic treatments eradicated the pathogens from the diseased tissues, but disease ratings made 1 year after the treatments indicated extended disease suppression. Phosphonate and mefenoxam treatments can effectively manage almond scion cankers caused by P. cactorum or P. citricola.

Genetic structure of the Anthyllis vulneraria L. s. l. species complex in Estonia based on AFLPs

2008 ◽  
Vol 3 (4) ◽  
pp. 442-450 ◽  
Author(s):  
Egle Köster ◽  
Elena Bitocchi ◽  
Roberto Papa ◽  
Silvia Pihu
Keyword(s):  
Species Complex ◽  
Fragment Length Polymorphism ◽  
Aflp Analysis ◽  
Data Sets ◽  
Geographic Scale ◽  
Aflp Data ◽  
Anthyllis Vulneraria ◽  
Directional Variation ◽  
Intraspecific Structure ◽  
Cryptic Taxa

AbstractAnthyllis vulneraria L. (Fabaceae) s. lato includes many cryptic taxa, ranging from 25 to 60 subspecies according to different authors. The delimitation of intraspecific taxa of A. vulneraria s. lato has always been complicated and inconsistent. Different data sets (multivariate analyses of morphological variation, allozymes, chloroplast SSRs and ITS) have not resolved the existing problem with distinguishing some subspecies. We used the amplified fragment length polymorphism (AFLP) analysis to describe the differentiation in this species complex and to characterize variation on a geographic scale. Some correlation was found between genetic variability and geographic distribution (western-eastern directional variation), but AFLP data analysis did not reveal clear intraspecific structure of the seven analysed taxa. The analysed specimens did not comprise groups correlated with the subspecies.

Detection and Characterization of QoI-Resistant Phytophthora cactorum and P. nicotianae Causing Leather Rot in Florida Strawberry

Plant Disease ◽  
2021 ◽  
Author(s):  
Marcus Vinicius Marin ◽  
Teresa E Seijo ◽  
Ellias Zuchelli ◽  
Natalia A. Peres
Keyword(s):  
Point Mutations ◽  
Crown Rot ◽  
Cytb Gene ◽  
Phytophthora Cactorum ◽  
Phytophthora Spp ◽  
Mitochondrial Cytochrome B ◽  
Qualitative Resistance ◽  
Selection Of ◽  
Qoi Resistance

Phytophthora cactorum and P. nicotianae cause leather rot (LR) of fruit and Phytophthora crown rot (PhCR) in strawberry. LR occurs sporadically but can cause up to 70% fruit loss when weather is conducive. In Florida's annual strawberry winter production system, PhCR can be severe, resulting in plant stunting, mortality, and severe yield loss. Currently, azoxystrobin is labeled for control of LR but not for PhCR. The aims of this research were i) to determine the sensitivity of P. cactorum and P. nicotianae isolates from strawberry to azoxystrobin and ii) to investigate mechanisms of QoI-resistance present in P. cactorum and P. nicotianae based on the known point mutations within the cytb gene. Isolates of both Phytophthora spp. causing LR and PhCR were collected from multiple strawberry fields in Florida between 1997 and 2020. Isolates were tested for sensitivity to azoxystrobin at 0, 0.01, 0.1, 1.0, 10, and 50 µg/ml on potato dextrose agar (PDA) amended with SHAM (100 µg/ml). Isolates were separated into two groups, sensitive isolates, with the 50% effective concentration (EC50) values lower than 1.0 µg/ml, and resistant isolates having EC50 values higher than 50 µg/ml. P. cactorum and P. nicotianae resistance to azoxystrobin was found for isolates collected after 2010. The first 450 nucleotides of the mitochondrial cytochrome b (cytb) gene were sequenced from a selection of resistant and sensitive isolates of both species. The G143A mutation reported to confer resistance to azoxystrobin was found in all resistant P. cactorum isolates. However, in P. nicotianae, qualitative resistance was observed, but the isolates lacked all the known mutations in the cytb gene. This is the first report of resistance to azoxystrobin in P. cactorum and P. nicotianae.

scholarly journals Characterization of Verticillium albo-atrum Field Isolates Using Pathogenicity Data and AFLP Analysis

Plant Disease ◽  
2003 ◽  
Vol 87 (6) ◽  
pp. 633-638 ◽  
Author(s):  
Sebastjan Radišek ◽  
Jernej Jakše ◽  
Andrej Simončič ◽  
Branka Javornik
Keyword(s):  
Fragment Length Polymorphism ◽  
Economic Losses ◽  
Aflp Analysis ◽  
Mild Form ◽  
Aflp Data ◽  
Green Pepper ◽  
Clear Separation ◽  
Pathogenicity Tests ◽  
Verticillium Albo Atrum

Since 1997, hop wilt induced by a virulent pathotype of Verticillium albo-atrum has caused considerable economic losses in hop fields in Slovenia. In all, 20 isolates of V. albo-atrum, including 12 from plants affected with the lethal form (PG2) of hop wilt, 6 from plants with the mild form (PG1), 1 from cucumber, and 1 from petunia, as well as 1 isolate of V. dahliae each from hop and green pepper, were analyzed by amplified fragment length polymorphism (AFLP). Differences in the virulence of hop isolates were confirmed by pathogenicity tests on hop cultivars. The AFLP method was optimized for analysis of these fungi and 7 of 39 primer combinations tested were used for the analysis of polymorphism among isolates. Cluster analysis of AFLP data divided the isolates into two, well-separated V. albo-atrum and V. dahliae clusters, confirming that the two species are genetically distinct. Within the V. albo-atrum cluster, isolates were further separated into two distinct groups: the A1 group contained PG1 hop pathotype and cucumber and petunia isolates, and the A2 group all hop isolates of the PG2 pathotype. Minor genetic variation was detected within pathotype-associated AFLP groups, but the clear separation of V. albo-atrum hop isolates according to their level of virulence shows genetic differentiation among hop V. albo-atrum pathotypes.

Sign in / Sign up

Export Citation Format

Share Document