scholarly journals Mobile Host mRNAs Are Translated to Protein in the Associated Parasitic Plant Cuscuta campestris

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 93
Author(s):  
So-Yon Park ◽  
Kohki Shimizu ◽  
Jocelyn Brown ◽  
Koh Aoki ◽  
James H. Westwood
Keyword(s):  
Vascular Tissue ◽  
Histochemical Staining ◽  
Mobile Host ◽  
Systemic Movement ◽  
Gus Reporter ◽  
Companion Cells ◽  
Localization Signal ◽  
Sieve Tubes ◽  
Host Parasite ◽  
Water Nutrients

Cuscuta spp. are obligate parasites that connect to host vascular tissue using a haustorium. In addition to water, nutrients, and metabolites, a large number of mRNAs are bidirectionally exchanged between Cuscuta spp. and their hosts. This trans-specific movement of mRNAs raises questions about whether these molecules function in the recipient species. To address the possibility that mobile mRNAs are ultimately translated, we built upon recent studies that demonstrate a role for transfer RNA (tRNA)-like structures (TLSs) in enhancing mRNA systemic movement. C. campestris was grown on Arabidopsis that expressed a β-glucuronidase (GUS) reporter transgene either alone or in GUS-tRNA fusions. Histochemical staining revealed localization in tissue of C. campestris grown on Arabidopsis with GUS-tRNA fusions, but not in C. campestris grown on Arabidopsis with GUS alone. This corresponded with detection of GUS transcripts in Cuscuta on Arabidopsis with GUS-tRNA, but not in C. campestris on Arabidopsis with GUS alone. Similar results were obtained with Arabidopsis host plants expressing the same constructs containing an endoplasmic reticulum localization signal. In C. campestris, GUS activity was localized in the companion cells or phloem parenchyma cells adjacent to sieve tubes. We conclude that host-derived GUS mRNAs are translated in C. campestris and that the TLS fusion enhances RNA mobility in the host-parasite interactions.

Morphological and histochemical analysis of galls of Lipara lucens (Diptera, Chloropidae) on Phragmites australis (Poaceae)

1998 ◽  
Vol 76 (8) ◽  
pp. 1374-1384 ◽  
Author(s):  
Inez Vandevyvere ◽  
Luc De Bruyn
Keyword(s):  
Phragmites Australis ◽  
Vascular Tissue ◽  
Common Reed ◽  
Histochemical Staining ◽  
Histochemical Analysis ◽  
Nutritive Tissue ◽  
Plant Insect Interactions ◽  
Pith Parenchyma ◽  
The Common ◽  
Insect Interactions

Lipara lucens Meigen (Diptera, Chloropidae) is a monophagous herbivore of the common reed, Phragmites australis Cav. (Trin.) ex Steud. (Poaceae), on which it induces typical cigar-shaped galls. In this paper, the anatomy and histochemistry of galls, cultivated in a greenhouse and collected in the field, were examined. Gall growth takes place while the larva feeds outside the actual developing gall. During gall growth, internode elongation is reduced. Internally, the pith parenchyma, destined to become the nutritive tissue, proliferates instead of degenerating as is seen in uninfested stems. The tissue cylinder around the gall chamber widens up to three times its normal size, while the pith parenchyma doubles its width. The central pith of nutritive cells becomes surrounded by an inner layer of longitudinal and an outer layer of radial parenchymatous cells. Vascular strands, likely connected to the vascular tissue of the host plant, run through this special band of parenchyma cells. The bundles are oriented perpendicular to the stem axis, surrounding the larval chamber. When the gall is completed, the larva gnaws through the growing point and enters the gall chamber, where it consumes the nutritive tissue. A sclerenchymatization process starts now resulting in an extremely hardened gall. Histochemical staining reveals the presence of proteins, DNA, RNA, and a gradient of lipid globules in the nutritive tissue. No starch was detected.Key words: plant-insect interactions, Lipara lucens, Phragmites australis, gall structure.

scholarly journals Fructose Utilization and Phytopathogenicity of Spiroplasma citri

2000 ◽  
Vol 13 (10) ◽  
pp. 1145-1155 ◽  
Author(s):  
Patrice Gaurivaud ◽  
Jean-Luc Danet ◽  
Frédéric Laigret ◽  
Monique Garnier ◽  
Joseph M. Bové
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Sources ◽  
Wild Type ◽  
Spiroplasma Citri ◽  
Companion Cells ◽  
Transmission Period ◽  
Sieve Tubes ◽  
Sucrose Loading

Spiroplasma citri is a plant-pathogenic mollicute. Recently, the so-called nonphytopathogenic S. citri mutant GMT 553 was obtained by insertion of transposon Tn4001 into the first gene of the fructose operon. Additional fructose operon mutants were produced either by gene disruption or selection of spontaneous xylitol-resistant strains. The behavior of these spiroplasma mutants in the periwinkle plants has been studied. Plants infected via leafhoppers with the wild-type strain GII-3 began to show symptoms during the first week following the insect-transmission period, and the symptoms rapidly became severe. With the fructose operon mutants, symptoms appeared only during the fourth week and remained mild, except when reversion to a fructose+ phenotype occurred. In this case, the fructose+ revertants quickly overtook the fructose¯ mutants and the symptoms soon became severe. When mutant GMT 553 was complemented with the fructose operon genes that restore fructose utilization, severe pathogenicity, similar to that of the wild-type strain, was also restored. Finally, plants infected with the wild-type strain and grown at 23°C instead of 30°C showed late symptoms, but these rapidly became severe. These results are discussed in light of the role of fructose in plants. Fructose utilization by the spiroplasmas could impair sucrose loading into the sieve tubes by the companion cells and result in accumulation of carbohydrates in source leaves and depletion of carbon sources in sink tissues.

scholarly journals Morphological, Anatomical and Palynological Studies on Endemic Matthiola anchoniifolia Hub. -Mor. (Brassicaceae)

2013 ◽  
Vol 5 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Mehmet TEKIN ◽  
Gülden YILMAZ ◽  
Esra MARTIN
Keyword(s):  
Cross Sections ◽  
Anatomical Study ◽  
Endemic Plant ◽  
Exine Ornamentation ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Pollen Shape ◽  
Periclinal Walls ◽  
First Time

In this paper, anatomical, palynological and seed micromorphological properties of an endemic plant Matthiola anchoniifolia Hub.-Mor. are recorded for the first time. A description and descriptive illustrations of the species are given based on the collected specimens for morphological study. Seed surface of M. anchoniifolia is examined by scanning electron microscope. The seed of M. anchoniifolia was compressed, brownish in colour and the cells of testa were nearly 60-80 μm in diameter and ranged from isodiametric, tetragonal or pentagonal. The anticlinal walls were straight or weakly curved while the outer periclinal walls were concave to flat with smooth surface. In anatomical study, cross sections of root, stem and stem leaf are examined. The root had secondary structure. Periderm consists of 5-8 layers of cells for phellem. Cortex consists of 9-12 layered parenchymatic tissue under the periderm. Secondary phloem ring-shaped, 6-9 layered and consists of companion cells and grouped sieve tubes. Stem had primary structure when analyzed. It is circular with a few irregular ribs in cross section. Cortex is 8-12 layered and parenchymatous. Stoma cells are present on both epidermis. Leaf is isobilateral. There are unicellular and ramified hairs on both surface. Palisade parenchyma cells are 1-2 layered and spongy parenchyma cells are 5-12 layered. M. anchoniifolia has tricolpate pollen type, prolate pollen shape and reticulate exine ornamentation.

scholarly journals MARCADORES ANATÔMICOS DO PECÍOLO E A TOLERÂNCIA À SECA DE PONTEIROS E AO DÉFICIT HÍDRICO EM EUCALIPTO

Nativa ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 591-596
Author(s):  
Samyra Alves Condé ◽  
Edgard Augusto de Toledo Picoli ◽  
Thais Roseli Corrêa ◽  
Rodrigo Dal Sasso Lourenço
Keyword(s):  
Water Stress ◽  
Vascular Tissue ◽  
Relevant Information ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Physiological Disorder ◽  
Cross Sectional ◽  
Water Nutrients ◽  
Different Levels ◽  
Selection Of

A seca de ponteiros em Eucalipto é um distúrbio fisiológico, onde o estresse hídrico vem sendo associado como um dos fatores intensificadores de sua ocorrência. A seleção precoce de genótipos de eucalipto tolerantes a essas condições, podem fornecer informações relevantes quanto a esse distúrbio. Objetivou-se avaliar possíveis marcadores anatômicos, associados a tolerância ao déficit hídrico e à seca de ponteiros. Genótipos comerciais com diferentes graus de suscetibilidade a seca de ponteiros foram submetidos a diferentes níveis de estresse hídrico em condições de casa de vegetação. A duração do experimento foi de 75 dias. Amostras de pecíolos foram coletadas e avaliadas as características das áreas anatômicas de: seção transversal, tecido vascular, xilema, floema e do córtex. Os dados foram submetidos à análise da variância (ANOVA) e para comparação de médias foi adotado o teste Tukey (p<0,05). Os resultados mostraram que há a tendência de redução de todas as variáveis avaliadas com o aumento do déficit hídrico. Entretanto, o genótipo tolerante em condições de maior restrição hídrica apresenta maior área de seção transversal e de tecidos condutores em comparação ao suscetível. A maior proporção destes tecidos sugere que o clone tolerante apresenta condição mais favorável ao transporte de água, fotoassimilados e nutrientes. Palavras-chave: melhoramento florestal; silvicultura; seleção genômica.   ANATOMICAL MARKERS OF PETIOLE AND TOLERANCE TO DIE-BACK AND WATER STRESS IN EUCALYPTUS   ABSTRACT: Die-Back in Eucalyptus is a physiological disorder where the water stress has been associated as an intensifier of this occurrence. The early selection of tolerant Eucalyptus genotypes to water stress can provide relevant information to this disorder. The research aimed to evaluate possible anatomical markers associated with tolerance to water stress and Die-Back. Commercial genotypes with different levels of susceptibility to this disorder were submitted to different levels of water stress in a greenhouse condition. The experiment lasted 75 days. Petioles samples were collected and anatomical characteristics were evaluated: cross-sectional area, area of vascular tissue, xylem area, phloem area and cortical area. The data were submitted to analysis of variance (ANOVA) and for the comparison of means was adopted Tukey test (p <0.05). The results show us that there is a tendency to reduce all variables with increasing water deficit. However, the tolerant genotype in higher water stress conditions has greater cross-sectional area and conducting tissues compared to susceptible genotype. The major proportion of these tissues suggests that the tolerant clone presents more favorable condition for transport of water, nutrients and assimilates. Keywords: forest improvement; forestry; genomic selection.

On the vascular anatomy and stomates of the lodicules of Zea mays

1980 ◽  
Vol 58 (9) ◽  
pp. 1045-1055 ◽  
Author(s):  
Thompson Demetrio Pizzolato
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Vascular Anatomy ◽  
Transfer Cells ◽  
Tracheary Elements ◽  
Cell Type ◽  
Xylem Parenchyma ◽  
Abaxial Epidermis ◽  
Companion Cells ◽  
Sieve Tubes

The four lodicules of the male spikelet of Zea mays L. are supplied by one, two, or three traces. In the lower regions of the traces intermediary cells and a few phloem transfer cells occur with the companion cells and sieve tubes. Xylem transfer cells with a variety of wall thickenings intermingle in the lower regions of the traces with tracheary elements. Tracheary elements and sieve tubes in this region do not touch but are separated by the phloem and xylem parenchyma. As the lodicule trace nears the base of the lodicule, intermediary cells and transfer cells diminish. A bundle sheath surrounds the lodicule trace but does not surround the minor veins of the lodicule proper. Within the lodicule proper the trace branches prolifically, and the minor veins become peripherally placed. Most of the minor veins contain vessels and sieve tubes but a few contain sieve tubes alone. Companion cells occur in some veins but not in others. Vessels and sieve tubes frequently touch each other. Many minor veins end simultaneously in sieve elements and tracheary elements but some end in one or the other cell type. Parenchyma cells with wrinkled walls occur near the minor veins. The abaxial epidermis of the upper regions of the lodicule contains stomates.

scholarly journals Changes of ultrastructure and cytoplasmic free calcium in Gladiolus x hybridus Van Houtte roots infected by aster yellows phytoplasma

2011 ◽  
Vol 72 (4) ◽  
pp. 269-282 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Calcium Ions ◽  
Infected Plant ◽  
Sieve Tube ◽  
Plant Roots ◽  
Free Calcium ◽  
Aster Yellows ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Sieve Tubes ◽  
Aster Yellows Phytoplasma

Roots of <em>Gladiolus </em>x <em>hybridus </em>Van Houtte plants infected with aster yellows phytoplasma were examined. The infected plants had a reduced root system in comparison to control plants. Their roots were thinner and the stele organisation was changed. Phytoplasmas were present in sieve tubes, companion cells and phloem parenchyma cells of the infected plant roots. Free calcium ions were localized in the cells of infected plants. Cells of the stele of infected roots, especially these infected with phytoplasmas, showed an increase of calcium antimonite deposits in theirs protoplasts. Also the number of calcium antimonite deposits increased in sieve tubes of infected roots. The deposits were present on plasma membrane, around the sieve tube plate and also in the lumen of the sieve tube. The increase of free calcium ions in sieve tubes did not cause the occlusion of sieve tube pores. Companion cells and some parenchyma cells with phytoplasmas did not react to phytoplasma infection with an increase of Ca<sup>2+</sup> ions in protoplast. The parenchyma cells showing signs of degeneration reacted with high increase of calcium ions. The Ca<sup>2+</sup> ions were present mainly in cytoplasm of infected parenchyma cells. There were calcium antimonite deposits in infected plant roots xylem elements and in intracellular spaces of cortex parenchyma. Such deposits were not present in control plants.

scholarly journals Cytopathological evidence for transport of phytoplasma in infected plants

2014 ◽  
Vol 68 (4) ◽  
pp. 261-266 ◽  
Author(s):  
Anna Rudzińska-Langwald ◽  
Maria Kamińska
Keyword(s):  
Morphological Changes ◽  
Close Contact ◽  
Infected Plant ◽  
Sieve Tube ◽  
Tagetes Patula ◽  
Plant Cell Walls ◽  
Companion Cells ◽  
Phytoplasma Infection ◽  
Sieve Tubes ◽  
Helichrysum Bracteatum

Pleomorphic phytoplasmas were observed in sieve tubes, companion cells and in phloem parenchyma of <em>Tagetes patula</em> L., <em>Helichrysum bracteatum</em> Willd. and <em>Gladiolus</em> sp. L. plants with morphological changes typical for phytoplasma infection. In the pores of the sieve plate phytoplasma cells were seen which suggests that the vertical transport of this pathogen goes in the sieve tubes of infected plants throughout the sieve tube pores. The contact of the sieve tube with the neighbouring cells goes through the plasmodesmata, but no changes of the plasmodesmata were observed in the phloem of infected plants. The size and structure of unchanged plasmodesmata does not allow passing through such big structures like phytoplasma. Instead close contact between phytoplasma cells and vertical sieve tube walls takes place. Damages to the cell wall were observed forming cavities in which the phytoplasma cells were present. The damages of parenchyma and companion cells walls also were seen. In cells where the damages of the walls were observed phytoplasmas were present. The phytoplasma cells were sporadically seen also in the intercellular spaces of parenchyma. These data suggest that horizontal transport depends on damages to the infected plant cell walls caused by the phytoplasma itself.

Are there contractile proteins present in phloem?

1980 ◽  
Vol 58 (7) ◽  
pp. 821-825 ◽  
Author(s):  
R. G. Thompson
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Respiratory Activity ◽  
Contractile Proteins ◽  
Low Molecular Weight ◽  
P Protein ◽  
Sieve Cells ◽  
Companion Cells ◽  
Willow Bark ◽  
Sieve Tubes

Actinlike structures have been found in companion cells and parenchyma of phloem and in young sieve cells, but not, according to recent work, in mature sieve tubes of angiosperms. Because of this, the question of whether P-protein is a contractile protein presents serious difficulties. Protein of low molecular weight found in phloem has not been as carefully examined as P-protein. Evidence to support contractile proteins in phloem as seen from the amino acid composition and respiratory activity of willow bark is also discussed.

scholarly journals Histochemical Study of the Progenetic TrematodeAlloglossidium renale

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Craig A. Schimmer ◽  
Stephen C. Landers
Keyword(s):  
Host Response ◽  
Histochemical Study ◽  
Living Organism ◽  
Histochemical Staining ◽  
Host Tissue ◽  
Host Cells ◽  
Positive Staining ◽  
Tubule Cells ◽  
Host Parasite ◽  
Highly Evolved

A histochemical study of the progenetic trematodeAlloglossidium renalehas demonstrated the absence of any secreted material between the adult worm and the host (freshwater shrimp) antennal gland tubules. Host tissue is affected only by the compression, abrasion, and ingestion by the parasite, and host tubule cells near the worm have the same staining patterns as those distant from the parasite. The trematode sometimes dies within the host, leaving a necrotic mass whose histochemical staining differs significantly from the living organism. In the necrotic mass, the only recognizable features were the ova and the vitellarium, which atrophied and resulted in tyrosine-positive staining within the mass. A melanin reaction was not observed in the host using a specialized ferro-ferricyanide stain. The only apparent host response to infection was a layer of damaged squamous host cells adhering to the necrotic worm. The results confirm benign host-parasite effects and a highly evolved relationship between the host and parasite, perhaps bordering on commensalism.

Sieve element biology provides leads for research on phytoplasma lifestyle in plant hosts

2019 ◽  
Vol 70 (15) ◽  
pp. 3737-3755 ◽  
Author(s):  
Aart J E van Bel ◽  
Rita Musetti
Keyword(s):  
Cell Biology ◽  
Sieve Element ◽  
Companion Cell ◽  
Electron Microscopic ◽  
Sieve Elements ◽  
Cell Complexes ◽  
Companion Cells ◽  
Phytoplasma Infection ◽  
Sieve Tubes ◽  
Physical And Chemical

Abstract Phytoplasmas reside exclusively in sieve tubes, tubular arrays of sieve element–companion cell complexes. Hence, the cell biology of sieve elements may reveal (ultra)structural and functional conditions that are of significance for survival, propagation, colonization, and effector spread of phytoplasmas. Electron microscopic images suggest that sieve elements offer facilities for mobile and stationary stages in phytoplasma movement. Stationary stages may enable phytoplasmas to interact closely with diverse sieve element compartments. The unique, reduced sieve element outfit requires permanent support by companion cells. This notion implies a future focus on the molecular biology of companion cells to understand the sieve element–phytoplasma inter-relationship. Supply of macromolecules by companion cells is channelled via specialized symplasmic connections. Ca2+-mediated gating of symplasmic corridors is decisive for the communication within and beyond the sieve element–companion cell complex and for the dissemination of phytoplasma effectors. Thus, Ca2+ homeostasis, which affects sieve element Ca2+ signatures and induces a range of modifications, is a key issue during phytoplasma infection. The exceptional physical and chemical environment in sieve elements seems an essential, though not the only factor for phytoplasma survival.

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