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Бутенкова, Алина Николаевна - One of the best experts on this subject based on the ideXlab platform.

  • Comparative analysis of the leaf anatomy of Phlox sibirica L. and Phlox sibirica var. borealis (Wherry) B. Boivin
    2020
    Co-Authors: Бутенкова, Алина Николаевна
    Abstract:

    In this comparative research of the leaf anatomy of Phlox sibirica and Phlox sibirica var. borealis, we discovered that morphometric features of the leaf blades structure in 95 % of cases significantly differ at a significance level of P < 0.05. Statistically significant differences were not found only in determining the stomatal index, the value of which also corresponds to other types of groundcover Phlox. The studied taxa are characterized by collateral vascular bundles, an anomocytic type of the stomatal apparatus and elongated, winding epidermal cells. Phlox sibirica is distinguished by a better development of collenchyma strands, which provides sheet rigidity even with the loss of turgor, xylem, and the most photosynthetically active layer of mesophyll (cells of the upper layer). Thus, in the anatomical structure of the studied Phloxes, the features characteristic of xerophytic-heliophytic species, more pronounced in Phlox sibirica, were revealed. The leaf anatomy of the studied taxa reflects their adaptation to conditions with an unfavorable water regime (ensures the maintenance of a normal water balance) and excessive lighting

Haengrae Cho - One of the best experts on this subject based on the ideXlab platform.

  • prototyping Phlox a high performance transaction processing system on a workstation cluster with shared disks
    IEEE Computer Society Workshop on Future Trends of Distributed Computing Systems, 2001
    Co-Authors: Raecha Hwang, Haengrae Cho
    Abstract:

    Coupling multiple workstations for high performance transaction processing has become increasingly attractive for reasons of capacity, cost, and availability. Phlox is a prototypical transaction processing system running on the workstation cluster with shared disks. Phlox supports a message oriented file system for database sharing, global cache coherency and concurrency control, affinity-based transaction routing, and sophisticated database recovery protocol. The paper describes the current prototype of Phlox and discusses some of the major design decisions that went into its construction. The lessons learned from this prototype and its predecessors are also presented.

  • FTDCS - Prototyping Phlox, a high performance transaction processing system on a workstation cluster with shared disks
    Proceedings Eighth IEEE Workshop on Future Trends of Distributed Computing Systems. FTDCS 2001, 1
    Co-Authors: Kyungoh Ohn, Raechan Hwang, Haengrae Cho
    Abstract:

    Coupling multiple workstations for high performance transaction processing has become increasingly attractive for reasons of capacity, cost, and availability. Phlox is a prototypical transaction processing system running on the workstation cluster with shared disks. Phlox supports a message oriented file system for database sharing, global cache coherency and concurrency control, affinity-based transaction routing, and sophisticated database recovery protocol. The paper describes the current prototype of Phlox and discusses some of the major design decisions that went into its construction. The lessons learned from this prototype and its predecessors are also presented.

Francesca Peduto Hand - One of the best experts on this subject based on the ideXlab platform.

  • Flaming Phlox and the Ubiquitous Powdery Mildew Disease
    Plant Health Progress, 2020
    Co-Authors: Coralie Farinas, Pablo Jourdan, Francesca Peduto Hand
    Abstract:

    Phlox is a diverse genus of ornamental plants that is native to the North American continent. These popular plants, which are known for flowers with “the color of glowing flame”, are particularly appreciated in naturalistic arrangements and increasingly emphasized in native gardens for their ability to attract pollinators. Despite the plant’s popularity, the main limitation to its cultivation is the fungal disease powdery mildew (PM). Hence, cultivars deployed through the years have been selected not just for desirable horticultural traits but also for resistance to PM. Although some studies on the Phlox-PM pathosystem have begun to unravel the mechanisms underpinning host-pathogen interactions, numerous questions remain unanswered, including what are the genes involved in the retarded senescence of the infected host tissue, what are the molecular mechanisms associated with the host ontogenic resistance, and what is the role of phytohormones in the resistance of Phlox to PM? PM pathogens, already predominant on Phlox, are now likely to be ubiquitous due to the exchange of plants throughout the world. Research into the genetic diversity of Phlox-PM populations will help identify the routes of disease spread and evolutionary potential of the pathogens. Here, we review what is known about Phlox and the PM disease, and we identify knowledge gaps that have yet to be addressed.

  • Phlox Species Show Quantitative and Qualitative Resistance to a Population of Powdery Mildew Isolates from the Eastern United States.
    Phytopathology, 2020
    Co-Authors: Coralie Farinas, Pablo Jourdan, Pierce A. Paul, Jason C. Slot, Margery L. Daughtrey, Veena Devi Ganeshan, Fulya Baysal-gurel, Francesca Peduto Hand
    Abstract:

    Ornamental plants in the genus Phlox are extensively planted in landscapes and home gardens around the world. A major limitation to a more widespread use of these plants is their susceptibility to powdery mildew (PM). In this study, we used multilocus sequence typing (MLST) analysis to gain insights into the population diversity of 32 Phlox PM pathogen (Golovinomyces magnicellulatus and Podosphaera sp.) isolates collected from the eastern United States and relate it to the ability to overcome host resistance. Low genetic diversity and a lack of structure were found within our population. Whole genome comparison of two isolates was used to support low genetic diversity evidence found with the MLST analysis. Recombination was suggested by the incongruences observed in the six phylogenetic trees generated from the housekeeping genes TEF-1α, CSI, ITS, IGS, H3, and TUB. Contrasting with low genetic diversity, we found high phenotypic diversity when using 10 of the 32 isolates to evaluate host resistance in four different Phlox species (P. paniculata 'Dunbar Creek', P. amoena OPGC 3598, P. glaberrima OPGC 3594, and P. subulata OPGC 4185) using in vitro bioassays. We observed quantitative and qualitative resistance in all Phlox species and a consistent low disease severity in our control, P. paniculata 'Dunbar Creek'. Taken together, the results generated in this study constitute a robust screening of popular Phlox germplasm that can be incorporated into breeding programs for PM resistance and provides significant information on the evolution of PM pathogens.

Sergey S. Simonov - One of the best experts on this subject based on the ideXlab platform.

Pablo Jourdan - One of the best experts on this subject based on the ideXlab platform.

  • Flaming Phlox and the Ubiquitous Powdery Mildew Disease
    Plant Health Progress, 2020
    Co-Authors: Coralie Farinas, Pablo Jourdan, Francesca Peduto Hand
    Abstract:

    Phlox is a diverse genus of ornamental plants that is native to the North American continent. These popular plants, which are known for flowers with “the color of glowing flame”, are particularly appreciated in naturalistic arrangements and increasingly emphasized in native gardens for their ability to attract pollinators. Despite the plant’s popularity, the main limitation to its cultivation is the fungal disease powdery mildew (PM). Hence, cultivars deployed through the years have been selected not just for desirable horticultural traits but also for resistance to PM. Although some studies on the Phlox-PM pathosystem have begun to unravel the mechanisms underpinning host-pathogen interactions, numerous questions remain unanswered, including what are the genes involved in the retarded senescence of the infected host tissue, what are the molecular mechanisms associated with the host ontogenic resistance, and what is the role of phytohormones in the resistance of Phlox to PM? PM pathogens, already predominant on Phlox, are now likely to be ubiquitous due to the exchange of plants throughout the world. Research into the genetic diversity of Phlox-PM populations will help identify the routes of disease spread and evolutionary potential of the pathogens. Here, we review what is known about Phlox and the PM disease, and we identify knowledge gaps that have yet to be addressed.

  • Phlox Species Show Quantitative and Qualitative Resistance to a Population of Powdery Mildew Isolates from the Eastern United States.
    Phytopathology, 2020
    Co-Authors: Coralie Farinas, Pablo Jourdan, Pierce A. Paul, Jason C. Slot, Margery L. Daughtrey, Veena Devi Ganeshan, Fulya Baysal-gurel, Francesca Peduto Hand
    Abstract:

    Ornamental plants in the genus Phlox are extensively planted in landscapes and home gardens around the world. A major limitation to a more widespread use of these plants is their susceptibility to powdery mildew (PM). In this study, we used multilocus sequence typing (MLST) analysis to gain insights into the population diversity of 32 Phlox PM pathogen (Golovinomyces magnicellulatus and Podosphaera sp.) isolates collected from the eastern United States and relate it to the ability to overcome host resistance. Low genetic diversity and a lack of structure were found within our population. Whole genome comparison of two isolates was used to support low genetic diversity evidence found with the MLST analysis. Recombination was suggested by the incongruences observed in the six phylogenetic trees generated from the housekeeping genes TEF-1α, CSI, ITS, IGS, H3, and TUB. Contrasting with low genetic diversity, we found high phenotypic diversity when using 10 of the 32 isolates to evaluate host resistance in four different Phlox species (P. paniculata 'Dunbar Creek', P. amoena OPGC 3598, P. glaberrima OPGC 3594, and P. subulata OPGC 4185) using in vitro bioassays. We observed quantitative and qualitative resistance in all Phlox species and a consistent low disease severity in our control, P. paniculata 'Dunbar Creek'. Taken together, the results generated in this study constitute a robust screening of popular Phlox germplasm that can be incorporated into breeding programs for PM resistance and provides significant information on the evolution of PM pathogens.

  • Genome size and ploidy levels of creeping Phlox and related germplasm of mat-forming taxa from eastern and western North America
    Scientia Horticulturae, 2016
    Co-Authors: Peter J. Zale, Dan Robarts, Pablo Jourdan
    Abstract:

    Abstract The eastern North American creeping Phlox ( Phlox subulata L.) is a widely cultivated flowering groundcover with a history of breeding and selection. Little is known about genome size variation and ploidy of P. subulata and related taxa. Mean holoploid (2C) and monoploid (1Cx) genome sizes and ploidy were analyzed with flow cytometry for a germplasm collection (n = 53) of 11 morphologically similar creeping Phlox taxa from natural plant populations, cultivars and hybrids obtained from nursery sources, and the related Microsteris gracilis . Holoploid genome sizes of accessions from natural populations were more variable than cultivated taxa and ranged from 7.47 to 22.86 pg and corresponded to diploid (2 n  = 2 x  = 14) tetraploid (2 n  = 4 x  = 28), and hexaploid (2 n  = 6 x  = 42) levels, but most accessions were diploid and genome size ranged from 7.60 to 8.47 pg. Two tetraploid accessions were discovered, but hexaploids were limited to one population of P. subulata . Most accessions consisted of a single cytotype, but intrapopulation differences in holoploid genome size were found among P. subulata and P. nivalis . The monoploid genome size of M. gracilis differed significantly from all Phlox, supporting separation of the genera. All cultivar accessions were diploid with genome sizes similar to wild diploid P. subulata , however Phlox  ×  procumbens had a mean genome size (8.73 pg) intermediate to parental taxa, P. stolonifera  ×  P. subulata, supporting hybrid origin. Knowledge of cytotype variation in Phlox germplasm will be useful for plant breeders, systematists, and conservationists.

  • Genome Size and Ploidy of Phlox paniculata and Related Germplasm in Subsections Paniculatae and Phlox
    Journal of the American Society for Horticultural Science, 2015
    Co-Authors: Peter J. Zale, Pablo Jourdan
    Abstract:

    Phlox is an important genus of herbaceous ornamental plants previously targeted for germplasm development, characterization, and enhancement by the U.S. Department of Agriculture, National Plant Germplasm System. Among Phlox in cultivation, Phlox paniculata is the most widely grown and intensively bred species, but little is known about variation in genome size and ploidy of this species or of related taxa that may be used for germplasm enhancement. The objective of this study was to assess cytotype variation in a diverse collection of cultivars and wild germplasm of P. paniculata (subsection Paniculatae) and of related taxa in subsections Paniculatae and Phlox. The collection included 138 accessions from seven species and two interspecific hybrids. Flow cytometry was used to estimate holoploid (2C) genome sizes and to infer ploidy levels. Chromosome counts were made to calibrate ploidy with genome size for a subset of taxa. Most cultivars were diploid (2n = 2x = 14) and had mean genome sizes that did not vary between subsections Paniculatae (14.33 pg) and Phlox (14.23 pg) although size variation was greater among cultivars within subsection Phlox. Triploid cultivars of P. paniculata, with a mean genome size of 21.36 pg and mitotic chromosome counts of 2n = 3x = 21, were identified. Such triploids suggests previous interploid hybridization within this taxon. Five tetraploid (2n = 4x = 28) cultivars were found in subsection Phlox; all were selections of P. glaberrima ssp. triflora, and had a mean genome size of 25.44 pg; chromosome counts in one of these confirmed they were tetraploid. The putative hybrid Phlox Suffruticosa Group ‘Miss Lingard’ showed an intermediate genome size of 21.21 pg supporting a triploid, hybrid origin of this taxon. Mean 2C genome sizes among wild-collected accessions were similar to values reported for cultivars (Paniculatae = 14.59 pg, Phlox = 14.23 pg), but taxa in subsection Phlox exhibited greater variation that included two tetraploids identified among wild-collected accessions; one, of P. pulchra, had a mean genome size of 26.17 pg, representing the first report of polyploidy in the taxon. This is the first report on genome size for the majority of species in the study. Although genome size could not be used to differentiate taxa in subsections Paniculatae and Phlox, the data provide further insights into cytotype variation of Phlox germplasm useful for plant breeders and systematists.