Association of phenol-containing structures with Apium graveolens resistance to Fusarium oxysporum f.sp. apii race 2

1989 ◽  
Vol 67 (11) ◽  
pp. 3153-3163 ◽  
Author(s):  
C. M. Jordan ◽  
L. S. Jordan ◽  
R. M. Endo
Keyword(s):  
Fusarium Oxysporum ◽  
Vascular System ◽  
Light And Electron Microscopy ◽  
Apium Graveolens ◽  
Cell Periphery ◽  
Xylem Parenchyma ◽  
Parenchyma Cells ◽  
Entire Plant ◽  
Phenolic Substances ◽  
Race 2

Electron-opaque (EO) structures were studied, using light and electron microscopy, in the xylem parenchyma cells and vessels of both incompatible and compatible Apium graveolens L. var. rapaceum (celeriac) and compatible Apium graveolens L. var. dulce (celery) roots 24 h after inoculation with Fusarium oxysporum f.sp. apii race 2. Few small EO bodies were observed in the noninoculated hosts. Histological, cytochemical, and chemical tests indicated the presence of phenolic substances and polysaccharides in the EO materials. These EO structures increased both in number and size as infection progressed. The incompatible host produced three and five times more of the EO materials than the compatible celeriac and celery, respectively. The amount of the EO materials and host compatibility were related to the absence and presence of fungal hyphae in the vascular system. Hyphae either associated with or enveloped by the EO structures were vacuolated; their cytoplasm was restricted to the cell periphery. Occlusion of the xylem vessel pores of the incompatible host with the EO structures likely prevented upward spread of the pathogen throughout the entire plant.

Penetration and colonization of resistant and susceptible Apium graveolens by Fusarium oxysporum f.sp. apii race 2: callose as a structural response

1988 ◽  
Vol 66 (12) ◽  
pp. 2385-2391 ◽  
Author(s):  
C. M. Jordan ◽  
R. M. Endo ◽  
L. S. Jordan
Keyword(s):  
Fusarium Oxysporum ◽  
Host Cell ◽  
Cell Walls ◽  
Vascular Tissue ◽  
Periodic Acid ◽  
Light And Electron Microscopy ◽  
Structural Response ◽  
Aniline Blue ◽  
Apium Graveolens ◽  
Race 2

Root apices of Apium graveolens L. resistant and susceptible to race 2 of Fusarium oxysporum f.sp. apii (R. Nels. & Sherb.) were studied at various times after inoculation, using light and electron microscopy to determine structural response(s) of the hosts during penetration and colonization by the pathogen. Penetration was intercellular and intracellular and involved mechanical and enzymatic mechanisms. At the onset of penetration, the host cell walls manifested fluorescence, induced with either aniline blue or sirofluor, at the point of penetration. The fluorescent area was more intense and larger in the resistant host. Fluorescence disappeared with time. After incubation with β-1,3 glucanase fluorescence disappeared, indicating β-1,3 polysaccharide (probably callose) presence. Callose deposits were 2 and 3 times greater in the epidermis and 4 and 9 times greater in the cortex of the resistant than in two susceptible hosts, respectively. Hyphal counts in the cortex of the resistant host were 50% fewer than in the susceptible hosts. Increased callose deposition on host cell walls was associated with reduced colonization. Callose formed in vascular tissue as the fungus colonized it. Callose detection with sirofluor was more sensitive; background fluorescence common with aniline blue without periodic acid – Schiff's reagent pretreatment was absent.

Light and electron microscopy localization of chloride ions in cells of Salicornia pacifica var. utahensis

1975 ◽  
Vol 53 (12) ◽  
pp. 1176-1187 ◽  
Author(s):  
W. M. Hess ◽  
D. J. Hansen ◽  
D. J. Weber
Keyword(s):  
Electron Microscopy ◽  
Vascular System ◽  
Silver Chloride ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Chloride Ions ◽  
Vascular Bundles ◽  
Silver Acetate ◽  
Parenchyma Cells ◽  
In Cells

Light and electron microscopy was used to determine the distribution of chloride ions in cells and tissues of Salicornia pacifica Standl, var. utahensis (Tidestrom) Munz. Chlorenchyma cells with chloroplasts around the periphery and sclereid-like cells with distinct wall thickenings which extended from the anastomosing vascular system to near the epidermis were present in the cortex. The vascular bundles or stelar strands were surrounded by several layers of large parenchyma cells. Tissues were treated with silver acetate for silver chloride precipitation. Silver chloride precipitation sites were present in all cell types. Precipitation sites were readily evident in the vacuoles but not in other organelles.

scholarly journals Occurrence of paracrystalloids and their particles in resistant and susceptible carnation plants infected with Fusarium oxysporum f.sp. dianthi race 2

2005 ◽  
Vol 85 (3) ◽  
pp. 139-151 ◽  
Author(s):  
Guillemond B. Ouellette ◽  
Danny Rioux ◽  
Marie Simard ◽  
Robert P. Baayen
Keyword(s):  
Fusarium Oxysporum ◽  
Resistant Cultivar ◽  
Susceptible Plant ◽  
Parenchyma Cells ◽  
Race 2 ◽  
As If

Abstract Uncommon, opaque particles (of approximately 20-22 nm, referred to as OP), aggregating into paracrystalloids occurred only next to colonized cells in carnation plants of either a susceptible or resistant cultivar (cv.) infected with Fusarium oxysporum f.sp. dianthi. In the susceptible plant, those structures occurred in vessel lumina and host walls, apparently associated with their alterations, but not in parenchyma cells, a situation which was the exact opposite of that observed in resistant plants. In comparison with apparently similar structures reported in other systems, paracrystalloids and their OPs did not seem to have exact counterparts in plants infected with viruses or fungi, although similar paracrystalloids were observed in nematode-infected plants. The OPs were associated in both cvs. with fine opaque matter, often displaying fine filamentous structures, and were in addition connected to fungal cells in the susceptible cv. Similar structures also extended through host walls into adjoining cells; these relations with parenchyma cells in resistant plants were interpreted as if the particles therein were akin to, if not exactly of the same nature as those in susceptible plants. As the opaque matter, the filamentous structures and the OPs were interrelated and associated with pathogen cells, it seemed warranted to assume that the OPs were issued from the pathogen.

Histochemistry of Reaction Wood Cell Walls in Two Species of Eucalyptus and in Tristania Conferta R.Br

1972 ◽  
Vol 20 (1) ◽  
pp. 9 ◽  
Author(s):  
G Scurfield
Keyword(s):  
Cell Walls ◽  
Structural Heterogeneity ◽  
Wall Layer ◽  
Reaction Wood ◽  
Xylem Parenchyma ◽  
Cell Wall Layer ◽  
Parenchyma Cells ◽  
Histochemical Tests ◽  
Phenolic Substances ◽  
Marked Tendency

The results of extensive histochemical tests carried out on the walls of reaction wood cells in the stems of Eucalyptus spp. and Tristania conferta are presented. They are interpreted on the basis of the known chemistry and structure of such walls. These, in their turn, are related to the location of the cells in the stems. Of particular interest is the histochemical and structural heterogeneity of cell wall layer G. This heterogeneity is discussed in relation to the penetration of G by lignin precursors of extracellular origin and the possible release of phenolic substances from the protoplasts of living reaction wood, ray, and xylem parenchyma cells. The presence of peroxidase in the G layer is confirmed, and the marked tendency of G to stain when supplied with certain phenols and hydrogen peroxide demonstrated. Reduced lignification of G is tentatively attributed to retardation of lignin precursor penetration of G rather than to a lack of precursor availability.

scholarly journals Xylem Parenchyma—Role and Relevance in Wood Functioning in Trees

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1247
Author(s):  
Aleksandra Słupianek ◽  
Alicja Dolzblasz ◽  
Katarzyna Sokołowska
Keyword(s):  
Woody Plants ◽  
Secondary Xylem ◽  
Vascular System ◽  
Research Interest ◽  
Present Review ◽  
Xylem Parenchyma ◽  
Wood Tissue ◽  
Parenchyma Cells ◽  
Heterogeneous Tissue ◽  
The Dead

Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field.

Encystment and germination of the parasitic chytrid Rozella allomycis on host hyphae

1973 ◽  
Vol 51 (10) ◽  
pp. 1825-1835 ◽  
Author(s):  
Abraham A. Held
Keyword(s):  
Cyst Wall ◽  
Germ Tube ◽  
Light And Electron Microscopy ◽  
Multivesicular Bodies ◽  
Cell Periphery ◽  
General Sequence ◽  
Obligate Intracellular ◽  
Host Cytoplasm ◽  
Intracellular Parasites ◽  
Three Stages

Zoospores of the obligately parasitic chytrid Rozella allomycis which settle upon hyphae of the water mold host, Allomyces arbuscula, encyst and germinate before their protoplasts penetrate into the host cytoplasm. This process has been examined by light and electron microscopy. Three stages which follow the attachment to the host and the retraction of the zoospore's flagellum are described: (1) the early cyst lacks a wall; it is discoid, and its shape is maintained by the coil of the retracted axoneme which forms its rim; (2) a cyst wall is formed while multivesicular bodies occur at the cell periphery and eventually disappear; a germ tube starts to grow at the point of attachment; and (3) the firm-walled cyst is spheroidal; it has a fully developed germ tube with a specialized class of vesicles; it also forms a distal, flattened vacuole whose swelling eventually injects the Rozella protoplast into the host; at this stage the retracted axoneme has disappeared and the cell's organelles have undergone extensive changes. Electron-dense, "gamma-like" granules enclosed in vacuoles may play a major role in the formation of both the cyst wall and the distal vacuole. These granules appear to give rise to small vesicles, and thus to multivesicular bodies; the distal vacuole appears to form by coalescense of gamma-like vacuoles.The general sequence of encystment and germination resembles that found in other Chytridiomycetes, both saprophytic and parasitic. However, the distal vacuole and the vesicles in the germ tube appear to be parasitic adaptations and are shared by obligate intracellular parasites from several unrelated groups of zoosporic fungi.

scholarly journals Marker Development for Differentiation of Fusarium oxysporum f. sp. Niveum Race 3 from Races 1 and 2

2021 ◽  
Vol 22 (2) ◽  
pp. 822
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
James C. Fulton ◽  
Pingsheng Ji ◽  
Nicholas S. Dufault ◽  
...  
Keyword(s):  
South Carolina ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Conventional Polymerase Chain Reaction ◽  
Detection Methods ◽  
Limiting Factors ◽  
Pcr Marker ◽  
Primer Sets ◽  
Race Differentiation ◽  
Race 2

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum (FON), is pathogenic only to watermelon and has become one of the main limiting factors in watermelon production internationally. Detection methods for this pathogen are limited, with few published molecular assays available to differentiate FON from other formae speciales of F. oxysporum. FON has four known races that vary in virulence but are difficult and costly to differentiate using traditional inoculation methods and only race 2 can be differentiated molecularly. In this study, genomic and chromosomal comparisons facilitated the development of a conventional polymerase chain reaction (PCR) assay that could differentiate race 3 from races 1 and 2, and by using two other published PCR markers in unison with the new marker, the three races could be differentiated. The new PCR marker, FNR3-F/FNR3-R, amplified a 511 bp region on the “pathogenicity chromosome” of the FON genome that is absent in race 3. FNR3-F/FNR3-R detected genomic DNA down to 2.0 pg/µL. This marker, along with two previously published FON markers, was successfully applied to test over 160 pathogenic FON isolates from Florida, Georgia, and South Carolina. Together, these three FON primer sets worked well for differentiating races 1, 2, and 3 of FON. For each marker, a greater proportion (60 to 90%) of molecular results agreed with the traditional bioassay method of race differentiation compared to those that did not. The new PCR marker should be useful to differentiate FON races and improve Fusarium wilt research.

scholarly journals Morphology and anatomy of leaf mine in Richterago riparia Roque (Asteraceae) in the campos rupestres of Serra do Cipó, Brazil

2002 ◽  
Vol 62 (1) ◽  
pp. 179-185 ◽  
Author(s):  
G. F. A. MELO DE PINNA ◽  
J. E. KRAUS ◽  
N. L. de MENEZES
Keyword(s):  
Host Plant ◽  
Vascular System ◽  
Glandular Trichomes ◽  
Protective Layer ◽  
Vascular Bundles ◽  
Campos Rupestres ◽  
Structural Alterations ◽  
Serra Do Cipó ◽  
Phenolic Substances

The leaf mine in Richterago riparia is caused by a lepidopteran larva (lepidopteronome). The leaves of R. riparia show campdodrome venation; the epidermis is unistratified, with stomata and glandular trichomes in adaxial and abaxial surfaces. The mesophyll is bilateral and the vascular system is collateral. During the formation of the mine, the larva consumes the chlorenchyma of the mesophyll and the smaller vascular bundles (veins of third and fourth orders). Structural alterations in the tissues of the host plant were not observed, except for the formation of a wound meristem and the presence of cells with phenolic substances next to the mine. Three cephalic exuviae of the miner were found in the mesophyll. This lepidopteronome is parenchymatic and the epidermis remains intact, but forms a protective layer for the mining insect.

scholarly journals Multiple Evolutionary Trajectories Have Led to the Emergence of Races in Fusarium oxysporum f. sp. lycopersici

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
V. Chellappan Biju ◽  
Like Fokkens ◽  
Petra M. Houterman ◽  
Martijn Rep ◽  
Ben J. C. Cornelissen
Keyword(s):  
Transposable Elements ◽  
Fusarium Oxysporum ◽  
Resistance Genes ◽  
Pcr Analysis ◽  
Genomic Fragment ◽  
Avirulence Genes ◽  
Content Type ◽  
Race 1 ◽  
Tomato Cultivars ◽  
Race 2

ABSTRACT Race 1 isolates of Fusarium oxysporum f. sp. lycopersici (FOL) are characterized by the presence of AVR1 in their genomes. The product of this gene, Avr1, triggers resistance in tomato cultivars carrying resistance gene I. In FOL race 2 and race 3 isolates, AVR1 is absent, and hence they are virulent on tomato cultivars carrying I. In this study, we analyzed an approximately 100-kb genomic fragment containing the AVR1 locus of FOL race 1 isolate 004 (FOL004) and compared it to the sequenced genome of FOL race 2 isolate 4287 (FOL4287). A genomic fragment of 31 kb containing AVR1 was found to be missing in FOL4287. Further analysis suggests that race 2 evolved from race 1 by deletion of this 31-kb fragment due to a recombination event between two transposable elements bordering the fragment. A worldwide collection of 71 FOL isolates representing races 1, 2, and 3, all known vegetative compatibility groups (VCGs), and five continents was subjected to PCR analysis of the AVR1 locus, including the two bordering transposable elements. Based on phylogenetic analysis using the EF1-α gene, five evolutionary lineages for FOL that correlate well with VCGs were identified. More importantly, we show that FOL races evolved in a stepwise manner within each VCG by the loss of function of avirulence genes in a number of alternative ways. IMPORTANCE Plant-pathogenic microorganisms frequently mutate to overcome disease resistance genes that have been introduced in crops. For the fungus Fusarium oxysporum f. sp. lycopersici, the causal agent of Fusarium wilt in tomato, we have identified the nature of the mutations that have led to the overcoming of the I and I-2 resistance genes in all five known clonal lineages, which include a newly discovered lineage. Five different deletion events, at least several of which are caused by recombination between transposable elements, have led to loss of AVR1 and overcoming of I. Two new events affecting AVR2 that led to overcoming of I-2 have been identified. We propose a reconstruction of the evolution of races in FOL, in which the same mutations in AVR2 and AVR3 have occurred in different lineages and the FOL pathogenicity chromosome has been transferred to new lineages several times.

Construction of a linkage map and identification of DNA markers linked to Fom-1, a gene conferring resistance to Fusarium oxysporum f.sp. melonis race 2 in melon

Euphytica ◽  
2009 ◽  
Vol 168 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Takahiro Tezuka ◽  
Keisuke Waki ◽  
Kazutoshi Yashiro ◽  
Maki Kuzuya ◽  
Tomoko Ishikawa ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Linkage Map ◽  
Dna Markers ◽  
Race 2
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