Biomedical subjects

Peter E Urwin

Publications and source records attributed to Peter E Urwin.

4 recordsLinked to original sources

PubMed2005

Cloning and characterisation of a Heterodera glycines aminopeptidase cDNA.

An aminopeptidase full-length cDNA (Hg-amp-1) was cloned from the adult female soybean cyst nematode Heterodera glycines by heterologous screening of a cDNA library with a Caenorhabditis elegans EST sequence. The predicted open reading frame encoded an 882-amino acid protein containing the conserved zinc-binding domain and GAMEN motif that are characteristic of M1 family aminopeptidases. The putative protein lacks any subcellular targeting signals and displays strong similarity to puromycin-sensitive aminopeptidases from C. elegans, Drosophila and mammals. Hg-amp-1 is expressed in juvenile nematodes and both male and female adults, with highest expression in gravid females. In situ mRNA hybridisation localised the Hg-amp-1 transcript to the genital primordium of pre-parasitic juvenile nematodes and the reproductive tract of adult females. Suppression of Hg-amp-1 transcript level by RNA-interference led to a 61% reduction in the number of female nematodes parasitising soybean roots 21 days post infection with infective juvenile nematodes that had been exposed to double-stranded RNA.

Amino Acid Sequence↗

PubMed2005

RNA interference and plant parasitic nematodes.

RNA interference (RNAi) has recently been demonstrated in plant parasitic nematodes. It is a potentially powerful investigative tool for the genome-wide identification of gene function that should help improve our understanding of plant parasitic nematodes. RNAi should help identify gene and, hence, protein targets for nematode control strategies. Prospects for novel resistance depend on the plant generating an effective form of double-stranded RNA in the absence of an endogenous target gene without detriment to itself. These RNA molecules must then become available to the nematode and be capable of ingestion via its feeding tube. If these requirements can be met, crop resistance could be achieved by a plant delivering a dsRNA that targets a nematode gene and induces a lethal or highly damaging RNAi effect on the parasite.

Animals↗

PubMed2004

Preferential expression of a plant cystatin at nematode feeding sites confers resistance to Meloidogyne incognita and Globodera pallida.

The expression patterns of three promoters preferentially active in the roots of Arabidopsis thaliana have been investigated in transgenic potato plants in response to plant parasitic nematode infection. Promoter regions from the three genes, TUB-1, ARSK1 and RPL16A were linked to the GUS reporter gene and histochemical staining was used to localize expression in potato roots in response to infection with both the potato cyst nematode, Globodera pallida and the root-knot nematode, Meloidogyne incognita. All three promoters directed GUS expression chiefly in root tissue and were strongly up-regulated in the galls induced by feeding M. incognita. Less activity was associated with the syncytial feeding cells of the cyst nematode, although the ARSK1 promoter was highly active in the syncytia of G. pallida infecting soil grown plants. Transgenic potato lines that expressed the cystatin OcIDeltaD86 under the control of the three promoters were evaluated for resistance against Globodera sp. in a field trial and against M. incognita in containment. Resistance to Globodera of 70 +/- 4% was achieved with the best line using the ARSK1 promoter with no associated yield penalty. The highest level of partial resistance achieved against M. incognita was 67 +/- 9% using the TUB-1 promoter. In both cases this was comparable to the level of resistance achieved using the constitutive cauliflower mosaic virus 35S (CaMV35S) promoter. The results establish the potential for limiting transgene expression in crop plants whilst maintaining efficacy of the nematode defence.

Journal Article↗

PubMed2003

Engineering plants for nematode resistance.

Biotechnology offers sustainable solutions to the problem of plant parasitic nematode control. There are several possible approaches for developing transgenic plants with improved nematode resistance; these include anti-invasion and migration strategies, feeding-cell attenuation, and antinematode feeding and development strategies. The essential elements of an effective control strategy are (a) genes that encode an antinematode effector protein, peptide or interfering RNA and (b) promoters that direct a specific pattern of expression for that effector. This review summarizes information on effectors that act directly against the nematode as well as those aimed at disrupting the nematode feeding site. We discuss patterns of promoter activity that could deliver expression of these effectors in a restricted and directed manner. Societal opposition to the technology of GM-nematode control is also discussed.

Animals↗