scholarly journals Developmental Transcript Profiling of Cyst Nematode Feeding Cells in Soybean Roots

2007 ◽  
Vol 20 (5) ◽  
pp. 510-525 ◽  
Author(s):  
Nagabhushana Ithal ◽  
Justin Recknor ◽  
Dan Nettleton ◽  
Tom Maier ◽  
Thomas J. Baum ◽  
...  
Keyword(s):  
Cell Wall ◽  
Soybean Cyst Nematode ◽  
Molecular Mechanisms ◽  
Cyst Nematode ◽  
Transcript Profiling ◽  
Cyst Nematodes ◽  
Root Cells ◽  
Genes Encoding ◽  
Soybean Roots ◽  
And Function

Cyst nematodes of the genus Heterodera are obligate, sedentary endoparasites that have developed highly evolved relationships with specific host plant species. Successful parasitism involves significant physiological and morphological changes to plant root cells for the formation of specialized feeding cells called syncytia. To better understand the molecular mechanisms that lead to the development of nematode feeding cells, transcript profiling was conducted on developing syncytia induced by the soybean cyst nematode Heterodera glycines in soybean roots by coupling laser capture microdissection with high-density oligonucleotide microarray analysis. This approach has identified pathways that may play intrinsic roles in syncytium induction, formation, and function. Our data suggest interplay among phytohormones that likely regulates synchronized changes in the expression of genes encoding cell-wall-modifying proteins. This process appears to be tightly controlled and coordinately regulated with cell wall rigidification processes that may involve lignification of feeding cell walls. Our data also show local downregulation of jasmonic acid biosynthesis and responses in developing syncytia, which suggest a local suppression of plant defense mechanisms. Moreover, we identified genes encoding putative transcription factors and components of signal transduction pathways that may be important in the regulatory processes governing syncytium formation and function. Our analysis provides a broad mechanistic picture that forms the basis for future hypothesis-driven research to understand cyst nematode parasitism and to develop effective management tools against these pathogens.

scholarly journals Modulations in Gene Expression and Mapping of Genes Associated with Cyst Nematode Infection of Soybean

2001 ◽  
Vol 14 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Zarir Vaghchhipawala ◽  
Ronald Bassüner ◽  
Kathryn Clayton ◽  
Kimberley Lewers ◽  
Randy Shoemaker ◽  
...  
Keyword(s):  
Gene Expression ◽  
Soybean Cyst Nematode ◽  
Genetic System ◽  
Cyst Nematode ◽  
Infection Process ◽  
Resistance Locus ◽  
Root Cells ◽  
Feeding Site ◽  
Susceptible Line ◽  
Scn Resistance

Infection of the soybean root by the soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) induces a well-documented, yet poorly understood, response by the host plant. The plant response, involving the differentiation of a feeding structure, or “syncytium,” facilitates the feeding and reproduction of the nematode to the detriment of the host. We used a genetic system involving a single dominant soybean gene conferring susceptibility to an inbred nematode strain, VL1, to characterize the nematode-host interaction in susceptible line PI 89008. The restriction fragment length polymorphism marker pB053, shown to map to a major SCN resistance locus, cosegregates with resistance among F2 progeny from the PI 89008 × PI 88287 cross. Cytological examination of the infection process confirmed that syncytium development in this genetic system is similar to that reported by others who used noninbred nematode lines. Our study of infected root tissue in the susceptible line PI 89008 revealed a number of genes enhanced in expression. Among these are catalase, cyclin, elongation factor 1α, β-1,3-endoglucanase, hydroxymethylglutaryl coenzyme A reductase, heat shock protein 70, late embryonic abundant protein 14, and formylglycinamidine ribonucleotide synthase, all of which we have genetically positioned on the public linkage map of soybean. Formylglycinamidine ribonucleotide synthase was found to be tightly linked with a major quantitative trait locus for SCN resistance. Our observations are consistent with the hypothesis proposed by others that feeding site development involves the dramatic modulation of gene expression relative to surrounding root cells.

scholarly journals A New Class of Ubiquitin Extension Proteins Secreted by the Dorsal Pharyngeal Gland in Plant Parasitic Cyst Nematodes

2004 ◽  
Vol 17 (8) ◽  
pp. 846-852 ◽  
Author(s):  
Tom Tytgat ◽  
Bartel Vanholme ◽  
Jan De Meutter ◽  
Myriam Claeys ◽  
Marjolein Couvreur ◽  
...  
Keyword(s):  
Syncytium Formation ◽  
Cyst Nematode ◽  
Heterodera Schachtii ◽  
Regulatory Function ◽  
Cyst Nematodes ◽  
New Class ◽  
Genes Encoding ◽  
Pharyngeal Gland ◽  
Positively Charged ◽  
Plant Parasitic

By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells. We hypothesize that the C-terminal peptide might have a regulatory function during syncytium formation in plant roots.

Response of soybean cyst nematodes and soybeans (Glycine max) to herbicides

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 264-270 ◽  
Author(s):  
Brian C. Levene ◽  
Micheal D.K. Owen ◽  
Gregory L. Tylka
Keyword(s):  
Glycine Max ◽  
Nonionic Surfactant ◽  
Untreated Control ◽  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Additive Effect ◽  
Cyst Nematodes ◽  
Population Densities ◽  
Soybean Cyst Nematodes

The effect of herbicides applied to V3 soybeans on race 3 soybean cyst nematode (SCN) reproduction and glyceollin production in roots was measured. Soybeans were treated postemergence with 1 × and 2 × rates of herbicides plus adjuvants or with adjuvants alone, and SCN development was measured. Acifluorfen, bentazon, lactofen, crop oil concentrate (COC), and nonionic surfactant (NIS) applications reduced SCN egg population densities 50 to 60% compared with the untreated control 4 and 8 wk after application. The SCN reproduction on plants treated with fluazifop-P, sethoxydim, and imazethapyr was similar to the untreated control. Crop oil concentrate or NIS applications alone were as effective as acifluorfen, bentazon, or lactofen applications for reducing SCN reproduction. However, no additive effect of adjuvant-herbicide combinations was observed, nor did herbicide rate affect SCN reproduction. Treatments reduced SCN reproduction only when applied to soybeans and had no effect on SCN reproduction when applied directly to the soil. No treatment stimulated SCN reproduction relative to the untreated control. Soybeans treated with COC, NIS, acifluorfen, and bentazon also had more glyceollin detected than the untreated control. Herbicide-induced glyceollin production may have increased the resistance of soybean to SCN.

scholarly journals Vegetative propagation of elite Eucalyptus clones as food source for honeybees (Apis mellifera); adventitious roots versus callus formation

2020 ◽  
Vol 67 (1-2) ◽  
pp. 83-97 ◽  
Author(s):  
Avi Eliyahu ◽  
Zvi Duman ◽  
Sara Sherf ◽  
Olga Genin ◽  
Yuval Cinnamon ◽  
...  
Keyword(s):  
Cell Wall ◽  
Adventitious Roots ◽  
Molecular Mechanisms ◽  
Callus Formation ◽  
Food Sources ◽  
Differential Staining ◽  
Outer Cell ◽  
Nectar Production ◽  
Root Cells ◽  
Cell Organization

Summer and autumn in Israel are highly arid with not enough plants in bloom offering nectar and pollen to support the local apiary. This leads to decline in colony health and honey production. To increase food sources for honeybees, we initiated a project to clone elite Eucalyptus trees exhibiting constant and rich blooming from late summer to early winter. We induced adventitious roots from cuttings of two mature Eucalyptus trees of which nectar production and honeybees’ attraction was measured: Eucalyptus brachyphylla and Eucalyptus x trabutii. During the rooting process, a high frequency of cylindrical callus formation instead of roots was obtained. To shed light on the inner anatomy of the callus chunks, we compared their cell organization and cell-wall composition to those of roots. Whereas in the root, cells were organized in circumferential symmetry, no symmetry was found in the callus. Instead, a more chaotic accumulation of meristematic-like cells with sporadic clusters of tracheary elements laid in different directions were observed. The outer cell layer of the callus often included swollen cells with thin cell walls. Most callus cells stained more strongly for cellulose and lignin than cells in the root meristem. In addition, specific antibodies to methylesterified and de-methylesterified pectin showed differential staining of callus vs. root cells indicating cell wall differences. Strikingly, roots were seen to differentiate from the chaotic cell organization of the callus, albeit at low rates. Further investigation of the cellular and molecular mechanisms underlying callus formation, are required.

scholarly journals A chromosomal assembly of the soybean cyst nematode genome

2021 ◽  
Author(s):  
Rick Masonbrink ◽  
Tom Maier ◽  
Matthew Hudson ◽  
Andrew Severin ◽  
Thomas Baum
Keyword(s):  
Soybean Cyst Nematode ◽  
Control Strategies ◽  
Cyst Nematode ◽  
Natural Resistance ◽  
Genetic Determinants ◽  
Safe Alternative ◽  
Root Cells ◽  
Long Read ◽  
Soybean Plants ◽  
Root Tissues

The soybean cyst nematode (Heterodera glycines) is a sedentary plant parasite that exceeds a billion dollars in yield losses annually. It has spread across the soybean-producing world, emerging as the primary pathogen of soybeans. This problem is exacerbated by H. glycines populations overcoming the limited sources of natural resistance in soybean and by the lack of effective and safe alternative treatments. Although there are genetic determinants that render soybean plants resistant to certain nematode genotypes, resistant soybean cultivars are increasingly ineffective because their multi-year usage has selected for virulent H. glycines populations. Successful H. glycines infection relies on the comprehensive re-engineering of soybean root cells into a syncytium, as well as the long-term suppression of host defenses to ensure syncytial viability. At the forefront of these complex molecular interactions are effectors, the proteins secreted by H. glycines into host root tissues. The mechanisms that control genomic effector acquisition, diversification, and selection are important insights needed for the development of essential novel control strategies. As a foundation to obtain this understanding, we developed a nine scaffold, 158Mb pseudomolecule assembly of the H. glycines genome using PacBio, Chicago, and Hi-C sequencing. An annotation of 22,465 genes was predicted using a Mikado pipeline informed by published short- and long-read expression data. Here we present results from our assembly and annotation of the H. glycines genome.

scholarly journals Corn and Soybean Host Root Endophytic Fungi with Toxicity Toward the Soybean Cyst Nematode

2020 ◽  
Vol 110 (3) ◽  
pp. 603-614 ◽  
Author(s):  
Noah Strom ◽  
Weiming Hu ◽  
Deepak Haarith ◽  
Senyu Chen ◽  
Kathryn Bushley
Keyword(s):  
Soybean Cyst Nematode ◽  
Plant Pathogens ◽  
Sequence Similarity ◽  
Fungal Endophytes ◽  
Cyst Nematode ◽  
Malt Extract ◽  
Ammonium Tartrate ◽  
Internal Transcribed Spacer Region ◽  
Culture Filtrates ◽  
Soybean Roots

Although fungal endophytes are commonly investigated for their ability to deter microbial plant pathogens, few studies have examined the activity of fungal root endophytes against nematodes. The soybean cyst nematode (SCN; Heterodera glycines), the most severe yield-limiting pathogen of soybean (Glycine max), is commonly managed through rotation of soybean with corn (Zea mays), a nonhost of the SCN. A total of 626 fungal endophytes were isolated from surface-sterilized corn and soybean roots from experimental plots in which soybean and corn had been grown under annual rotation and under 1, 3, 5, and 35 years of continuous monoculture. Fungal isolates were grouped into 401 morphotypes, which were clustered into 108 operational taxonomic units (OTUs) based on 99% sequence similarity of the full internal transcribed spacer region. Morphotype representatives within each OTU were grown in malt extract broth and in a secondary metabolite-inducing medium buffered with ammonium tartrate, and their culture filtrates were tested for nematicidal activity against SCN juveniles. A majority of OTUs containing isolates with nematicidal culture filtrates were in the order Hypocreales, with the genus Fusarium being the most commonly isolated nematicidal genus from corn and soybean roots. Less commonly isolated taxa from soybean roots included the nematophagous fungi Hirsutella rhossiliensis, Metacordyceps chlamydosporia, and Arthrobotrys iridis. Root endophytic fungal diversity in soybean was positively correlated with SCN density, suggesting that the SCN plays a role in shaping the soybean root endophytic community.

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