Dr. Rosane Hazelman Cunha Curtis Molecular host/parasite interactions Department of Plant Pathogen Interactions, Rothamsted Research Limited, Harpenden, Hertfordshire, AL5 2JQ, UK. Telephone: +44 (0)1582 763133 x2220. Fax: +44 (0)1582 760981 rosane.curtis@bbsrc.ac.uk

I have graduated in Medical Biology and have been formally trained as an immunologist and as a parasitologist of tropical parasites of medical and veterinary importance.  I have always been interested in the study of host-parasite interactions.  My PhD was concerned with the tropical parasite Schistosoma mansoniand I described and characterised several hydrolases and surface antigens. During this work the immunoprophylatic potential of these antigens was evaluated using passive and active immunizations. Two serine proteases were considered important therapeutic targets.

After completing the work for my PhD, I joined Rothamsted-Research and I have since been working with plant parasitic nematodes. My research involves the identification of nematode molecules that are important for the host-parasite interaction and can be used as targets in novel control strategies.

Research

The long-term aims of this research is to study molecular plant-nematode interactions, with emphasis on PCN interactions, to learn about the nature and function of nematode parasitism genes and of plant host factors needed for the nematode to complete their life cycle. The overall aim of this research is to identify novel targets, from both nematodes and plants, which are useful for nematode control strategies.

Molecular host/parasite interactions

This research aims to identify molecules from the nematode and host plants, which can be used as targets in novel nematode control strategies. Plant parasitic nematodes have a dynamic surface that interacts with external factors leading to surface modifications crucial to the establishment of host infection. In collaboration with Prof. John Kusel from the University of Glasgow we have demonstrated that root exudates and phytohormones can trigger alterations in surface lipophilicity of plant nematodes, possibly involving protein kinases in the signal transduction (Fig. 1a and b)  (Lopez de Mendoza et al., 2000, Akhkha et al., 2002 and 2004). We hypothesised that receptors located on the nematode surface or at the amphids might be responsible for sensing these host cues. Understanding infection mechanism involving phytohormones and other host cues may help in developing biopesticides to control nematode invasion of plants.

Nematode cuticular proteins have also been shown to be abundantly secreted by the parasitic stages in planta and were shown to bind to root cells forming the nematode feeding site (Fig. 2a and b) (Lopez, et al., 2002; Abrantes & Curtis, 2002). Therefore, they are considered to be potentially important for the plant nematode interactions.

Interference with nematode movement or host location or both can have adverse effects on nematode survival and invasion of plants. Our research has demonstrated that blocking key nematode secretions can interfere with nematode behaviour and consequently invasion of plants. Monoclonal antibodies specific to secretions present on the nematode cuticle surface and amphids were able to stop nematode movement and invasion of host plants (Fig. 3 and b) (Fioretti, et al., 2002). Therefore, these amphidial and cuticle surface proteins are potential targets to interfere with nematode development, they may stop invasion and/or migration inside the root tissue.

In collaboration with Dr. David Bird from the NCSU we are also interested to understand how plant parasites re-directs normal plant function to form the feeding cells, and have used tomato microarrays to directly and simultaneously examine thousands of root genes which might respond to invading Globodera sp. In particular, we are interested in genes that regulate key features of giant cell function, and the effector networks they control (Fig. 4). The downstream biochemistry makes a very attractive target for disruption in a transgenic plant, because it will lessen the pressure for emergence of resistance-breaking nematodes

Recent Refereed Publication:

§         Lopez, M., Modha, J., Roberts, C., Curtis, R.H.C. & Kusel, J. (2000) Observations of the changes of the surface cuticle of parasitic nematode using fluorescent probes.  Parasitology, 120: 203-209.

§         Gray, LJ, Curtis, RHC & Jones, J. (2001).  Characterisation of a collagen gene subfamily from the potato cyst nematode Globodera pallida. Gene, 67-75.

§         Fioretti,L., Warry, A, Burrows, P. & Haydock, P., Curtis, R.H.C.  (2001). Identification and immunolocalisation of an annexin (Gp-nex) in Globodera pallida. Nematology, 3: 45-54.

§         Abrantes, I. & Curtis, R.H.C. (2002). Immunolocalisation of a putative cuticular collagen in several developmental stages of Meloidogyne arenaria, Globodera rostochiensis and G. pallida. Journal of Helminthology, 76: 1-6.

§         Sharon, E., Spiegel, Y., Solomon, R. & Curtis, R.H.C. (2002). Characterization of Meloidogyne javanica surface coat using antibodies and their effect on nematode behaviour. Parasitology, 125: 177-1

§         Akhkha, A., Kusel, J., Kennedy, M. & Curtis, R.H.C. (2002). Effects of phytohormones on the surfaces of plant parasitic nematodes. Parasitology, 125: 165-175.

§          Lopez de Mendoza, ME & Curtis, RHC. (2002). In vivo immunolocalisation of surface antigens and excreted and secreted products of Trichinellla spiralis L₁.International Journal for Nematology, 12: 55-58.

§          Keon, R. Curtis, H. Cabrera and J. Hargreaves. (2003) Genomics approach to crop pest and disease research. Pesticide Management Science, 59(2): 143-147.

§         Fioretti, L. Porter, A., Haydock, P. & Curtis, R.H.C. (2003). Monoclonal antibodies reactive with secreted-excreted products from the amphids and the cuticle surface of Globodera pallida affect nematode movement and delay invasion of potato plants.  International Journal for Parasitology, 32: 1709-171.

§         Barros, L.M., Curtis, R.H.C., Viana, A.M., Campos, L & Carneiro, M. (2003). Fused Ro1A protein enhances B-glucoronidase activity 50 -fold: implications for Ro1A mechanism of action. Protein and Peptide Letters, 10 (3): 303-311, 2003.

§         Chen, Q., Brown, D.J.F., Curtis, R.H.C. & Jones, J. (2003). Development of the magnetic capture system for recovery of Xiphinema americanum. Nematology, 5: 359-366, 2003.

§         Chen, Q., Brown, D.J.F., Curtis, RHC, & Jones, JT. (2003). Development of magnetic capture system for recovery of Xiphinema americanus. Association of Applied Biologists, 283-289.

§         Doenhoff, M.J., Stanley, R.,  Price, D., Curtis, R.H.C., Parry, H., Griffiths, K. & Jackson, C.L. (2003). Identification of a fibrinolytic enzyme in Schistosome mansoni eggs and modulated fibrinogen metabolism in S. mansoni infected mice. Parasitology. 126, 231-234, 2003.

§         Akhakha, A., Curtis, RHC, Kennedy, M. & Kusel, J. (2004). The potential signaling pathways which regulate surface changes unduced by phytohormones in the potato cyst nematode (Globodera rostochiensis). Parasitology, 128: 533-539.