scholarly journals Multiple Nodulation Genes Are Up-Regulated During Establishment of Reniform Nematode Feeding Sites in Soybean

2018 ◽  
Vol 108 (2) ◽  
pp. 275-291 ◽  
Author(s):  
Nathan W. Redding ◽  
Paula Agudelo ◽  
Christina E. Wells
Keyword(s):  
Syncytium Formation ◽  
Parasitic Nematodes ◽  
Nodule Formation ◽  
Cell Cycle Regulators ◽  
Reniform Nematode ◽  
Feeding Site ◽  
Sugar Transporters ◽  
Feeding Sites ◽  
Growth System ◽  
And Control

The semi-endoparastic reniform nematode (Rotylenchulus reniformis) infects over 300 plant species. Females penetrate host roots and induce formation of complex, multinucleate feeding sites called syncytia. While anatomical changes associated with reniform nematode infection are well documented, little is known about their molecular basis. We grew soybean (Glycine max) in a split-root growth system, inoculated half of each root system with R. reniformis, and quantified gene expression in infected and control root tissue at four dates after inoculation. Over 6,000 genes were differentially expressed between inoculated and control roots on at least one date (false discovery rate [FDR] = 0.01, |log2FC| ≥ 1), and 507 gene sets were significantly enriched or depleted in inoculated roots (FDR = 0.05). Numerous genes up-regulated during syncytium formation had previously been associated with rhizobia nodulation. These included the nodule-initiating transcription factors CYCLOPS, NSP1, NSP2, and NIN, as well as multiple nodulins associated with the plant-derived peribacteroid membrane. Nodulation-related NIP aquaporins and SWEET sugar transporters were induced, as were plant CLAVATA3/ESR-related (CLE) signaling proteins and cell cycle regulators such as CCS52A and E2F. Nodulins and nodule-associated genes may have ancestral functions in normal root development and mycorrhization that have been co-opted by both parasitic nematodes and rhizobial bacteria to promote feeding site and nodule formation.

The reniform nematode, Rotylenchulus macrosoma, infecting olive in southern Spain

Nematology ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Pablo Castillo ◽  
Nicola Vovlas ◽  
Alberto Troccoli
Keyword(s):  
Southern Spain ◽  
Reniform Nematode ◽  
Morphometric Characters ◽  
Feeding Site ◽  
Feeding Sites ◽  
Heavy Soil ◽  
Soil Infestation ◽  
Olea Europea ◽  
Wild Olive ◽  
Pericycle Cells

Abstract Severe root infection of wild olive (Olea europea L. ssp. sylvestris), together with heavy soil infestation by the reniform nematode Rotylenchulus macrosoma, was detected in a natural wild olive orchard on sandy soil in Cádiz province, Andalucía, southern Spain. Most, but not all, of the morphometric characters of this population agreed with those reported for immature and adult females and males in previously studied populations. Sedentary immature and mature females showed a semi-endoparasitic feeding habit in wild and cultivated olives (cvs Arbequina and Picual). Naturally infected roots of wild olive responded to nematode infection identically to artificially infected olive planting stocks. The feeding site induced by R. macrosoma on olive roots consists of a stelar syncytium, which originates from an endodermal cell enlarging by a curved sheet of pericycle cells formed by hypertrophy of pericycle cells adjacent to the feeding cell. There were obvious anatomical differences between the feeding sites induced by R. macrosoma and R. macrodoratus on olive roots.

scholarly journals Nematode-Induced Changes of Transporter Gene Expression in Arabidopsis Roots

2005 ◽  
Vol 18 (12) ◽  
pp. 1247-1257 ◽  
Author(s):  
Ulrich Z. Hammes ◽  
Daniel P. Schachtman ◽  
R. Howard Berg ◽  
Erik Nielsen ◽  
Wolfgang Koch ◽  
...  
Keyword(s):  
Gene Families ◽  
Transcript Abundance ◽  
Giant Cells ◽  
Transport Processes ◽  
Transfer Cells ◽  
Parasitic Nematodes ◽  
Feeding Site ◽  
Feeding Sites ◽  
The Many ◽  
And Function

Root-knot plant-parasitic nematodes (Meloidogyne spp.) account for much of the damage inflicted to plants by nematodes. The feeding sites of these nematodes consist of “giant” cells, which have characteristics of transfer cells found in other parts of plants. Increased transport activity across the plasma membrane is a hallmark of transfer cells, and giant cells provide nutrition for nematodes; therefore, we initiated a study to identify the transport processes that contribute to the development and function of nematode-induced feeding sites. The study was conducted over a 4-week period, during which time the large changes in the development of giant cells were documented. The Arabidopsis ATH1 GeneChip was used to identify the many transporter genes that were regulated by nematode infestation. Expression of 50 transporter genes from 18 different gene families was significantly changed upon nematode infestation. Sixteen transporter genes were studied in more detail using real-time reverse-transcriptase polymerase chain reaction to determine transcript abundance in nematode-induced galls that contain giant cells and uninfested regions of the root. Certain genes were expressed primarily in galls whereas others were expressed primarily in the uninfested regions of the root, and a third group was expressed evenly throughout the root. Multiple transport processes are regulated and these may play important roles in nematode feeding-site establishment and maintenance.

How do nematodes get their sweets? Solute supply to sedentary plant-parasitic nematodes

Nematology ◽  
2007 ◽  
Vol 9 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Julia Hofmann ◽  
Florian Grundler
Keyword(s):  
Nutrient Supply ◽  
Heterodera Schachtii ◽  
Transport Systems ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Cyst Nematodes ◽  
Root Knot Nematodes ◽  
Feeding Sites ◽  
Inorganic Solutes ◽  
Nematode Development

AbstractSedentary cyst and root-knot nematodes withdraw large amounts of solutes from feeding structures induced in host roots. The feeding structures are specialised cells with a high metabolic activity and a tremendous capacity in translocation of nutrients. The required nutrients are provided by the plant transport systems – water and inorganic solutes from the xylem, assimilates such as sugars and amino acids from the phloem. Here we discuss the available data on the mechanisms by which nutrients are translocated into the nematode feeding sites. The interaction between Heterodera schachtii and Arabidopsis thaliana serves as a model system for cyst nematodes. In this case sufficient data are available to propose a conclusive concept for the mechanisms of nutrient flow: basically, in the early stages of nematode development syncytia are symplasmically isolated, so that transport proteins are responsible for the nutrient supply. Later, connections to the phloem via plasmodesmata are established, so that developing females are well supplied with assimilates. The interactions of root-knot nematodes with their hosts share a number of similarities but the data currently available are not sufficient to draw similar conclusions. As nutrient supply and functionality of feeding structures are the basis of biotrophic parasitism of sedentary nematodes, it is tempting to unravel the mechanisms by which both plant and nematodes influence each other via nutrient fluxes.

scholarly journals A Role for AtWRKY23 in Feeding Site Establishment of Plant-Parasitic Nematodes

2008 ◽  
Vol 148 (1) ◽  
pp. 358-368 ◽  
Author(s):  
Wim Grunewald ◽  
Mansour Karimi ◽  
Krzysztof Wieczorek ◽  
Elke Van de Cappelle ◽  
Elisabeth Wischnitzki ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Feeding Site ◽  
Plant Parasitic

scholarly journals Ecological and Behavioral Drivers of Supplemental Feeding Use by Roe Deer Capreolus capreolus in a Peri-Urban Context

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2088
Author(s):  
Federico Ossi ◽  
Nathan Ranc ◽  
Paul Moorcroft ◽  
Priscilla Bonanni ◽  
Francesca Cagnacci
Keyword(s):  
Roe Deer ◽  
Seasonal Pattern ◽  
Capreolus Capreolus ◽  
Camera Traps ◽  
Circular Statistics ◽  
Supplemental Feeding ◽  
Urban Context ◽  
Feeding Site ◽  
Feeding Sites ◽  
Use Of Resources

Winter supplemental feeding of ungulates potentially alters their use of resources and ecological interactions, yet relatively little is known about the patterns of feeding sites use by target populations. We used camera traps to continuously monitor winter and spring feeding site use in a roe deer population living in a peri-urban area in Northern Italy. We combined circular statistics with generalized additive and linear mixed models to analyze the diel and seasonal pattern of roe deer visits to feeding sites, and the behavioral drivers influencing visit duration. Roe deer visits peaked at dawn and dusk, and decreased from winter to spring when vegetation regrows and temperature increases. Roe deer mostly visited feeding sites solitarily; when this was not the case, they stayed longer at the site, especially when conspecifics were eating, but maintained a bimodal diel pattern of visits. These results support an opportunistic use of feeding sites, following seasonal cycles and the roe deer circadian clock. Yet, the attractiveness of these artificial resources has the potential to alter intra-specific relationships, as competition for their use induces gatherings and may extend the contact time between individuals, with potential behavioral and epidemiological consequences.

Feeding-Site Selection and Foraging Strategies of American Woodcock

The Auk ◽  
1983 ◽  
Vol 100 (3) ◽  
pp. 711-716 ◽  
Author(s):  
Dale L. Rabe ◽  
Harold H. Prince ◽  
Donald L. Beaver
Keyword(s):  
Laboratory Experiments ◽  
Search Pattern ◽  
Foraging Strategies ◽  
Feeding Site ◽  
American Woodcock ◽  
Feeding Sites ◽  
Scolopax Minor ◽  
Moisture Regimes ◽  
Feeding Site Selection

Abstract Live-trapped, adult American Woodcock (Scolopax minor) were tested in a series of laboratory experiments designed to evaluate the role of soil as a proximal cue for selecting feeding sites and to investigate foraging strategies for capturing earthworms (Lumbricidae). Foraging trials were conducted in a circular arena and showed that color, which tends to be correlated with the soil types and moisture regimes preferred by earthworms, was an important proximal cue for selecting feeding sites. Woodcock captured earthworms most efficiently in areas of relatively high prey density, because they used a nonrandom search pattern following an initial capture.

scholarly journals An Evaluation of Dazomet Incorporation Methods on Soilborne Organisms and Pine Seedling Production in Southern Nurseries

2003 ◽  
Vol 27 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Stephen W. Fraedrich ◽  
L. David Dwinell
Keyword(s):  
Morphological Characteristics ◽  
High Rate ◽  
Parasitic Nematodes ◽  
Seedling Production ◽  
Seedling Density ◽  
The North ◽  
Nursery Plant ◽  
Shoot Weight ◽  
And Control

Abstract The use of dazomet as a fall and spring fumigant for pine seedling production and control of soilborne pests was evaluated at two southern nurseries. Dazomet was applied at low (280–325 kg/ha) and high (493–560 kg/ha) rates and incorporated with a rototiller or spading machine. Comparisons were made with methyl bromide/chloropicrin (MBC) fumigation and nonfumigated control treatments. Dazomet incorporation method had no effect on seedling density at either nursery, and often did not affect seedling morphological characteristics. At the Georgia (GA) nursery, seedling density and morphological characteristics did not differ among fumigant treatments except in the spring study area where shoot weight was greater in the MBC treatment than the dazomet or nonfumigated control treatments. In the fall study area at the North Carolina (NC) nursery, seedling density was greater in the high-rate dazomet treatment than the nonfumigated control. Seedlings were generally larger in MBC and dazomet treatments than the control. Seedling density and morphological characteristics did not differ among fumigation treatments in the spring study area. Fumigation with MBC or dazomet generally reduced the percentage of roots withPythium andFusarium spp. compared to controls at the GA nursery and the fall fumigation area in the NC nursery. Plant parasitic nematodes were found infrequently at both nurseries and did not differ among treatments. Nutsedge (Cyperus spp.) was the major problem at the GA nursery and was effectively controlled only with MBC. Compared to the MBC treatment, the abundance of soilborne fungi and the association of certain types ofTrichoderma with roots was often lower in the dazomet treatments. The importance of these differences for long term seedling production and management of soilborne diseases is not known at this time. South. J. Appl. For. 27(1):41–51.

The reversibility of constraints on size and fecundity in the parasitic nematode Strongyloides ratti

Parasitology ◽  
2006 ◽  
Vol 133 (4) ◽  
pp. 477-483 ◽  
Author(s):  
M. E. VINEY ◽  
M. D. STEER ◽  
C. P. WILKES
Keyword(s):  
Immune Response ◽  
Parasitic Nematode ◽  
Host Immune Response ◽  
Parasitic Nematodes ◽  
Per Capita ◽  
And Control

The size and fecundity of parasitic nematodes are constrained by the host immune response. For the parasitic nematode of rats, Strongyloides ratti, parasitic females infecting immunized rats are smaller and less fecund than those infecting naïve rats. Here, we investigated whether these constraints on size and fecundity are life-long. This was done by comparison of worms from different immunization and immunosuppression regimes. It was found that the per capita fecundity of parasitic females of S. ratti is fully reversed, but that their size is only partially reversed, if previously immunized hosts are subsequently immunosuppressed, suggesting that fecundity is not subject to life-long constraints. The host immune response also resulted in allometric changes in the parasitic females. The significance of these results with respect to the growth and control of nematode fecundity are discussed.

scholarly journals Effect of terrain heterogeneity on feeding site selection and livestock movement patterns

2015 ◽  
Vol 55 (3) ◽  
pp. 298 ◽  
Author(s):  
Derek W. Bailey ◽  
Mitchell B. Stephenson ◽  
Marco Pittarello
Keyword(s):  
Site Selection ◽  
Early Morning ◽  
Livestock Grazing ◽  
Heterogeneous Environments ◽  
Feeding Site ◽  
Gps Collars ◽  
Feeding Sites ◽  
Nutrient Profiles ◽  
Tracking Period ◽  
Feeding Site Selection

Feeding site selection is a critical part of livestock foraging that can constrain and/or increase the choices available during diet selection. When livestock choose new feeding sites, vegetation and nutrient profiles can differ from other areas, especially in heterogeneous environments with rugged terrain. Correspondingly, livestock should remain longer in feeding sites in rugged heterogeneous pastures than in homogeneous pastures where animals may alternate among feeding sites to facilitate diet mixing and to prevent satiation. The objective of this study was evaluate how terrain and corresponding heterogeneity may affect the sequence and pattern of feeding site selection of free-roaming livestock. Grazing patterns of mature cows were evaluated on six ranches located in Arizona, Montana and New Mexico. In total, 11–19 cows were tracked for 1–3-month periods at each ranch by using global positioning system (GPS) collars. Positions were recorded at 10- or 15-min intervals and used to identify where cows grazed during the early morning (0500 hours to 1000 hours). Pastures (336–9740 ha) at each ranch were divided into seven to nine sections (48–1082 ha) as an indicator of feeding sites. Classification was based on cattle density and topographical and vegetation types. Sequences of daily section selection were evaluated using transition matrixes. For all ranches, the sequence of section selection differed from what would be expected by chance, indicating that the section selected on the following day depended on the section selected on the previous day. For ranches with relatively gentle terrain, cattle selected different feeding sites ~70% of the tracking period. In contrast, cows at the ranch with the largest pasture and enclosing both mountainous and gentle terrain stayed in the same feeding site for over 10 successive days for 42% of the tracking period. Smaller pastures with only mountainous terrain were intermediate. Cows grazing gentle topography and relatively homogeneous vegetation alternated among feeding sites (sections in the present study) more frequently than cows grazing pastures with more rugged topography and more heterogeneous vegetation. This pattern could help livestock mix forages and select a more diverse diet.

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