Inducible Flavone in Oats (Avena sativa) Is a Novel Defense Against Plant-Parasitic Nematodes

The induction of defense compounds in oats (Avena sativa) in response to invasion by parasitic nematodes and to application of the wound hormone methyl jasmonate was examined. Oats cv. Quoll seedlings were challenged with Pratylenchus neglectus, Heterodera avenae, and Ditylenchus dipsaci and treated with 1 × 10-4 M methyl jasmonate. Three compounds, isolated in methanolic root and shoot extracts of oats, exhibiting an absorbance spectrum typical of flavone glycosides, were induced by nematode invasion and methyl jasmonate. These were identified as flavone-C-glycosides by mass spectrometry. The effect of the flavone-C-glycosides on the invasion by and development of cereal cyst nematode H. avenae was assessed using methanolic extracts of shoots and roots from methyl jasmonate-treated plants. Both extracts impaired nematode invasion and development. When the extracts were fractionated by high voltage paper electrophoresis, only one flavone-C-glycoside, O-methyl-apigenin-C-deoxyhexoside-O-hexoside, inhibited nematode invasion. The protective effect of the induction of flavone-C-glycosides in oats by methyl jasmonate was evaluated against H. avenae and P. neglectus. Treatment with methyl jasmonate reduced invasion of both nematodes and increased plant mass, compensating for damage caused by the nematodes, and is attributed to the active flavone-C-glycoside. The active compound, O-methyl-apigenin-C-deoxyhexoside-O-hexoside, has not been implicated previously in plant defense against any pest or pathogen, and appears to provide protection against the major cereal nematodes Heterodera and Pratylenchus.

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Immunolocalisation of secreted-excreted products of Meloidogyne spp. using polyclonal and monoclonal antibodies

Fitopatologia Brasileira ◽

10.1590/s0100-41582005000600010 ◽

2005 ◽

Vol 30 (6) ◽

pp. 629-633 ◽

Cited By ~ 3

Author(s):

Liziane M. Lima ◽

Maria F. Grossi-de-Sa ◽

Railene A. Pereira ◽

Rosane H.C. Curtis

Keyword(s):

Monoclonal Antibodies ◽

Control Strategies ◽

Cross Reactivity ◽

Heterodera Avenae ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Second Stage ◽

Plant Nematode ◽

Meloidogyne Spp ◽

Host Parasite

Molecules expressed at the surface cuticle (SC) of plant parasitic nematodes represent the primary plant-nematode interface, and together with secreted-excreted (S-E) products are probably the first signals perceived by the host. These molecules, which are released into plant tissue, probably play important roles in the host-parasite interactions. Characterisation of these antigens will help in the identification of nematode targets useful for novel control strategies, which interfere with the nematode infection of plants. Three monoclonal (MAbs) and three polyclonal (PAbs) antibodies produced to S-E products of Meloidogyne spp. and Heterodera avenae were used to examine their reactivity towards M. incognita and/or M. arenaria second stage juveniles and adult females. The three PAbs showed cross-reactivity with M. incognita and M. arenaria. Antibody Roth-PC 373 strongly recognised molecules present in the SC, amphids and intestine, antibody Roth-PC 389 recognised the nematode amphids and metacorpus, while antibody Roth-PC 419 bound to molecules present in the subventral glands. Reactivity of the MAbs was only tested against M. arenaria. Monoclonal antibody Roth-MAb T116C1.1 showed intense reactivity with molecules present in the amphidial and phasmidial glands. Monoclonal antibodies Roth-MAb T46.2 and T42D.2 labeled the nematode amphids and molecules present in the nematode oesophagus (metacorpus), respectively.

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RNAi-mediated Resistance against Plant Parasitic Nematodes of Wheat Plants Obtained in Vitro Using Bioregulators of Microbiological Origin

Current Chemical Biology ◽

10.2174/2212796812666180507130017 ◽

2019 ◽

Vol 13 (1) ◽

pp. 73-89 ◽

Cited By ~ 3

Author(s):

Victoria A. Tsygankova ◽

Yaroslav V. Andrusevich ◽

Elena N. Shysha ◽

Lyudmila O. Biliavska ◽

Tatyana O. Galagan ◽

...

Keyword(s):

Flag Leaf ◽

Molecular Genetic ◽

Triticum Aestivum L ◽

Leaf Length ◽

Heterodera Avenae ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Flag Leaf Length ◽

Plant Parasitic

Background:Plant parasitic nematodes are dangerous pests that damage various agricultural crops and decrease their productivity.Objective:The resistance of new lines of wheat (Triticum aestivum L.) plants obtained under in vitro conditions on MS media containing microbial bioregulators to plant parasitic nematodes was studied under in vitro and greenhouse conditions.Methods:Here we conducted physiological and molecular-genetic studies of resistance of wheat plants to nematodes.Results:In vitro experiments showed that wheat plants grown on MS media with microbial bioregulators had 20-37 % of infestation with cereal cyst nematode Heterodera avenae, significantly lower when compared with 73 % of infestation of the control plants grown without bioregulators. Bioregulators increased morphometric parameters of the wheat plants obtained under in vitro conditions on MS media and further grown under greenhouse conditions on the natural invasive background: stem height increased 13.6-37.5 %, flag leaf length 18.0-19.3 %, ear length 6.8-24.6 %, and ear weight 27.0- 54.5 %, when compared with control wheat plants. The difference in the degree of hybridizated molecules mRNA and si/miRNA from control and experimental wheat plants increased: 15-39 % in plants grown under in vitro conditions on the invasive background created by H. avenae and 33-56 % in seeds of plants grown under greenhouse conditions on the natural invasive background. The silencing activity of si/miRNA from wheat plants grown on MS media with bioregulators increased: 20-51 % in plants grown under in vitro conditions on the invasive background created by H. avenae or 38-64 % in plants grown under greenhouse conditions on the natural invasive background.Conclusion:Our studies confirm the RNAi-mediated resistance to plant nematodes of wheat plants obtained on media with microbial bioregulators and grown under in vitro and greenhouse conditions.

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Discrimination of Plant-Parasitic Nematodes from Complex Soil Communities Using Ecometagenetics

Phytopathology ◽

10.1094/phyto-08-13-0236-r ◽

2014 ◽

Vol 104 (7) ◽

pp. 749-761 ◽

Cited By ~ 6

Author(s):

Dorota L. Porazinska ◽

Matthew J. Morgan ◽

John M. Gaspar ◽

Leon N. Court ◽

Christopher M. Hardy ◽

...

Keyword(s):

False Positive ◽

Plant Pathogens ◽

False Negative ◽

Heterodera Avenae ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Sampling Errors ◽

Sources Of Error ◽

Dna Sampling ◽

Plant Parasitic

Many plant pathogens are microscopic, cryptic, and difficult to diagnose. The new approach of ecometagenetics, involving ultrasequencing, bioinformatics, and biostatistics, has the potential to improve diagnoses of plant pathogens such as nematodes from the complex mixtures found in many agricultural and biosecurity situations. We tested this approach on a gradient of complexity ranging from a few individuals from a few species of known nematode pathogens in a relatively defined substrate to a complex and poorly known suite of nematode pathogens in a complex forest soil, including its associated biota of unknown protists, fungi, and other microscopic eukaryotes. We added three known but contrasting species (Pratylenchus neglectus, the closely related P. thornei, and Heterodera avenae) to half the set of substrates, leaving the other half without them. We then tested whether all nematode pathogens—known and unknown, indigenous, and experimentally added—were detected consistently present or absent. We always detected the Pratylenchus spp. correctly and with the number of sequence reads proportional to the numbers added. However, a single cyst of H. avenae was only identified approximately half the time it was present. Other plant-parasitic nematodes and nematodes from other trophic groups were detected well but other eukaryotes were detected less consistently. DNA sampling errors or informatic errors or both were involved in misidentification of H. avenae; however, the proportions of each varied in the different bioinformatic pipelines and with different parameters used. To a large extent, false-positive and false-negative errors were complementary: pipelines and parameters with the highest false-positive rates had the lowest false-negative rates and vice versa. Sources of error identified included assumptions in the bioinformatic pipelines, slight differences in primer regions, the number of sequence reads regarded as the minimum threshold for inclusion in analysis, and inaccessible DNA in resistant life stages. Identification of the sources of error allows us to suggest ways to improve identification using ecometagenetics.

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Can plants with good anthelmintic activity against free-living and animal parasitic nematodes be effective against plant parasitic nematodes?

10.1055/s-0039-3399736 ◽

2019 ◽

Author(s):

FN Makhubu ◽

MC Khosa ◽

LJ McGaw

Keyword(s):

Anthelmintic Activity ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Free Living ◽

Plant Parasitic

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Management of Plant-Parasitic Nematodes in Florida Cotton Production

EDIS ◽

10.32473/edis-ng015-2017 ◽

2017 ◽

Vol 2017 (2) ◽

pp. 8

Author(s):

Zane Grabau

Keyword(s):

Parasitic Nematodes ◽

Cotton Production ◽

Plant Parasitic Nematodes ◽

Fact Sheet ◽

Plant Parasitic

This 8-page fact sheet written by Zane J. Grabau and published in January 2017 by the UF Department of Entomology and Nematology explains how to diagnose and manage nematode problems in cotton production.http://edis.ifas.ufl.edu/ng015

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