Prof. Phil Jones Project Leader: Tropical Virology Unit

This is the home page of The Tropical Virus Unit which is led by Phil Jones. Phil's research interests are diseases of tropical crops caused by viruses and phytoplasmas. The work of the TVU falls into 3 areas

Diagnostic services
Knowledge transfer
Research

Diagnostic services

The TVU specialises in the diagnosis of virus and phytoplasma diseases as part of the CABI Global Plant Clinic.

We are currently collaborating with the Plant Protection Division of the Secretarial for the Pacific Communities on a virus and phytoplasma survey of many of the islands in the pacific.

If you would like to use our expertise please download our query forms and a copy of our Import permit which will help speed your samples through UK Customs. We do make a charge for our services but if you are working in a developing country or your country is a member of CABI you may qualify for our free service. http://www.rothamsted.ac.uk/ppi/tvu/ttvu.html

Knowledge transfer

- In country training courses
- UK based, visitors, students

In 2002 Phil, in conjunction with John Thomas a plant virologist at the Queensland Department of Agriculture organised and ran a course of Advances Diagnostics for Viruses and Phytoplasmas at the national institute for Plant Protection, Hanoi Vietnam as part of an ACIAR-CABI capacity-building project.

Phil provided the plant virology input to the DFID project - Pests and Diseases of potato in the Mesothermic valleys of Bolivia (funded through the Crop Protection Program of NRInternational). The project was based in the town of Comorapa, Santa Cruz Province.

The project involved virus surveys, on-farm trials and the establishment of a plant clinic. The project enjoyed exceptional support from the Municipality of Comorapa and was very successful in engaging the cooperation of farmers and growers.

The main virus diseases were: potato virus Y, potato leaf roll, Andean potato latent, Andean potato mottle, and potato virus X. the major source of infection was through the seed with some primary spread through aphid vectors. Incidence of the viruses varied from valley to valley. During the project we identified a stolbor-like phytoplasma that caused up to 90% infection in some crops. This disease was previously attributed to infection by Rhizoctonia solani - 'rhizoctoniosis' but has been renamed as 'Brotes Grandes' of potato.

The TVU hosts many visitors either as short term or longer term as in the case of MSc and PhD students. If you would like more information about working with the TVU please go to the Rothamsted International page.

Research

Phil's main research interests are the phytoplasmas, prokaryote plant pathogens of the class Mollicutes that cause over 700 diseases mainly in tropical and sub-tropical crops. Phytoplasmas can cause spectacular losses in perennial crops. In the Caribbean and Africa Coconut lethal yellowing phytoplasmas have caused the deaths of millions of coconut palms threatening the livelihood of tens of thousands of smallholder families. Research at Rothamsted has characterised the African coconut phytoplasmas that cause diseases such as Cape St Paul wilt (Ghana), Awka (Nigeria) and coconut lethal decline (Kenya, Tanzania and Mozambique).

Phytoplasmas have not yet been cultured and so the fulfilment of Koch's Postulates can only be done by consistent association. Phytoplasmas are transmitted by grafting, dodder, insect (Auchenorrhyncha) vectors and in some cases by seed although the mechanism for this is not fully understood.

Rothamsted International fellow Ivan Cordova of the Centro de Investigacion Cientifica de Yucatan, Mexico investigated the presence of phytoplasmas in embryos taken from LY infected palms using in situ PCR. He demonstrated that DNA from the LY phytoplasma could be localised in embryo sections.

Phil is currently investigating the aetiology and epidemiology of Kalimantan wilt of coconuts in Indonesia in collaboration with Sonny Warokka of the Research institute for Coconut and Palmae, Manado, Sulawesi, Indonesia.

Kalimantan wilt is a lethal disease that kills palms between 8 and 16 moths of the first appearance of symptoms. Symptoms are typified by a wilting of the lower fronds which spreads up through the crown until only a telegraph pole remains. There have been a number of previous studies into this disease but no attributable cause could be found. The project is using molecular diagnostics for phytoplasmas in both palms and putative insect vectors. You can find our more about vectors of phytoplasmas by visiting www.phytoplasma-vector.com.

Some recent publications:

Mpunami, A. Tymon, A. Jones, P. Dickinson, M. J Identification of potential vectors of the coconut lethal disease phytoplasma. Plant Pathology, 2000. 49: 3, 355-361

Cronje CPR Dabek AJ Jones P Tymon AM 2000. First report of a phytoplasma associated with a disease of date palms in North Africa. Plant Pathology, 49: 801.

Cronje CPR Dabek AJ Jones P Tymon AM 2000 Slow decline a new disease of mature date palms in North Africa associated with a phytoplasma, Plant Pathology. 49: 804

Khan A.J., Azam K.M., Deadman M.L., Al-Subhi A.M., Jones P., 2001. First Report of Alfalfa Witches Broom Disease in Oman caused by a Phytoplasma of the 16Sr II Group. Plant Disease, 85: 1287, 2001, published on-line as D-2001-0922-01N, 2001.

Pandit MK, Nath PSC, Mukopadhyay S, Devonshire BJ, Jones P. 2001. First report of Dasheen mosaic virus in elephant foot yam in India, Plant Pathology, 50: 802.

Kumarasinghe N C, Jones P. 2001. Identification of white leaf disease of sugarcane in Sri Lanka. Sugar Technology, 3: 55-58.

Da Silva P, Jones P, Shaw M W. 2002. Identification and transmission of Piper yellow mottle virus and cucumber mosaic virus infecting black pepper in Sri Lanka. Plant Pathology, 61: 537-545.

Harrison N A., Myrie W, Jones P, Carpio M L, Castillo M, Doyle M M, Oropeza C. 2002. 16S rRNA interoperon sequence heterogeniety distinuishes strain populations of the palm lethal yellowing phytoplasma in the caribbean region. Annals of Applied Biology, 141: 183-193.

Cordova I, Jones P, Harrison N A, Oropeza C. 2003. In situ PCR Detection of Phytoplasma DNA in Embryos from Coconut Palms with Lethal Yellowing Disease. Molecular Plant Pathology, 4: 99-108.