Symbiosis Control

 

Symbiotic control is a modern method of controlling human and plant disease pathogens that are vectored by insects. It originated in the Chagas and Tsetse fly projects at Yale University in the laboratories of Frank Richards. A project to control Rice Stripe Virus in China was also initiated there. These projects are designed to control pathogens of disease by use of symbionts to deliver anti-disease strategies. All of the projects are collaborative in nature. Collaboration is essential because the tools necessary to achieve the solution come from different disciplines and often the solutions are developed in one location and applied in another.

Over the past 7 years, several new projects have emerged that fall in the category of symbiotic control. In 1999-2000 we started a project at UC Riverside aimed at controlling Pierce’s disease of grapevines in California. The Yale projects were used as a model to set up the Riverside project guided by Frank Richards’ assertion that paratransgenesis (symbiotic control) could be used to control any insect-transmitted pathogen causing plant disease. To put this in perspective in California there are no immediate solutions to diseases caused by insect-transmitted pathogens in plants. The normal methods of dealing with plant diseases of this nature are wide-spread spraying to reduce the presence of the vector insect (as in Curly Top Virus), regular detection and removal of the diseased plants (as in Tristeza virus of citrus trees) or imposition of restrictive quarantines. Long term solutions include development of resistant varieties.

New applications for symbiotic control are emerging on a regular basis. Dr. Simona Palermo then with Alberto Alma at the University of Turin, Italy became aware of symbiotic control approaches during late 2003. She organized a group of interested colleagues in Italy and preliminary arrangements were made for her to come to Riverside to learn more about the Pierce’s disease approach. Before this happened Simona was offered a position she could not ignore and left the project. Instead three of us from Riverside and Yale paid an informal visit to Milan June 16-17, 2004 where we discussed setting up a collaborative group to work on symbiotic control of Flavescence dorée.

A summary of that meeting is available upon request. One decision was to set up websites at each symbiotic control project and describe each project and collaboration at a central web site with connections and links designed to foster collaborations.

 

Summary

Summary of meetings in Milan, Italy about symbiotic control of insect-transmitted pathogens of plant diseases. 

T. A. Miller

June 16, 2004 

Colleagues present and meeting times: 

Daniele.daffonchio@unimi.it

Pierattilio.bianco@unimi.it

Massimo.marzorati@unimi.it

Fabioqua@libero.it

Frank.richards@yale.edu

Thomas.miller@ucr.edu

Soookmiller@yahoo.com 

 

Met at Tulip Inn, Milan, Italy at 3:00 pm on Sunday June 13 and all drove separately to the University of Milan where projection equipment was available.  

Summary of discussions:

Daniele Daffonchio and Piero Bianco made presentations and Massimo Marzorati also made a power point presentation on Flavescence dorée (grape yellows). The presentations described the biology of the disease and the insect, including the difficulty of working on the insect and disease organism, the spiroplasmid. Massimo presented the grape yellows disease cycle as a triangle of plant, insect and pathogen and that the only way presently to interfere with the disease is at the insect corner with insecticides treatments.  

Discussions adjourned some time after 6 p.m. and Piero Bianco hosted Tom  ans Soo-ok Miller and Frank Richards for dinner.  

We met again at 10 am., Monday morning, June 14, 2004 at the Tulip Inn in Milan.  

 

Colleagues present:

Alberto.alma@unito.it

Rosemarie.tedeschi@unito.it

Daniele.daffonchio@unimi.it

Frank.richards@yale.edu

Thomas.miller@ucr.edu

Soookmiller@yahoo.com 

 

We discussed the research needed to apply symbiotic control to grape yellows, using Pierce’s disease and Chagas disease as models. The main difficulties are inability to culture spiroplasma, short life cycle of the vector insects, great difficulty in detecting the pathogen (absence of detection does not necessarily mean absence of the pathogen) and absence of a convenient measure of the disease cycle. We discussed possible funding and what might be necessary to achieve sufficient funding.  

Information on economic damage of the disease as a way of defining the urgency of finding a solution was mentioned as well as the need for a method of measuring the disease cycle to hasten bioassay of possible reagents for use in symbiotic control.  

Frank Richards mentioned that the symbiont used in Chagas disease was intimately associated with the vector insect until vitamin B was made available in the diet, when the symbiont is readily lost to the hindgut. He mentioned that is was important to obtain a profile of the symbionts associated with the insect as a means of assessing the best symbiont to use for a symbiotic control strategy.  

At the leafhopper Congress in St. Petersburg, Alberto Alma presented a graphs of the life cycle of Scaphoideus titanus, and distributions the vector of the spiroplasmid causing grape yellows. He presented maps of the presence of the insect and pathogen and latitude of invasions. All of these illustrative materials are very important and very useful as well as the history of appearance and spread of the disease. Similar information was presented on Sunday, June 13.  

It was mentioned that Claudio Bandi in Milan works on Wolbachia (of nematodes). Frank Richards mentioned that Wolbachia is still a candidate for the symbiont used in symbiotic control strategies despite the extreme difficulty of working with Wolbachia as a laboratory object.  

It was mentioned that hurdles exist in obtaining government approvals in symbiotic control strategies, but that one advantage is absence of genetically altered plants or insects.  

The suggestion was made that one way to develop a continuing contact between the research groups was to develop a website dedicated to symbiotic control as a method. There seemed to be agreement and some discussion centered on how to do this. Riverside was offered as a site for a serve to support a website, and Daniele offered to develop one in Milan.  

Included below are suggestions for what to induce on such a website: 

 

1. Definition of symbiotic control (SC).
2. Descriptions of diseases and other objects of SC.
3. Descriptions of research groups working on SC projects.
4. News about progress in SC or new projects.
5. Publications and resumes of principal participants (by URL links).
6. Descriptions of economic damage that would be useful in grant applications.
7. Bioremediation as a type of SC.
8. Links to scientific societies.
9. Links to scientific meetings pertinent to SC.
10. Information on scientific meetings pertinent to SC.
11. Regulatory activity pertinent to SC.
12. Links between medical and agricultural applications in SC.
13. Sponsors of SC research.

 

All of these elements would support communication between principal researchers and foster interactions.  

The Italian group:

 

• Entomologists: Dr Alberto Alma and Rosemarie Tedeschi, University of Torino.
• Entomologists: Dr Alberto Alma and Rosemarie Tedeschi, University of Torino.
• Plant pathologists: Dr Piero Attilio Bianco, Dr Paola Casati, Dr Fabio Quaglino and colleagues from the Department of Plant Pathology, University of Milano).
• Microbiologists: Dr Daniele Daffonchio and Massimo Marzorati from the Department of Food and Microbiological Science and Technology of the University of Milan. 

 

The American group:

 

• Entomologists: T. A. Miller and Blake Bextine, UC Riverside.
• Plant pathologists: Donald Cooksey, Plant Pathology Department, UC Riverside.
• Microbiologists: Carol Lauzon, California State University, Hayward, CA; David Lampe, Biology Department, Duquesne University, Pittsburgh, PA; Steven Lindow, Microbiology Department, UC Berkeley.  

 

Others:

 

• Ravi Durvasula, Yale Medical School, New Haven, CT; Serap Aksoy, Public Health School, Yale University, New Haven; Roger Hull, John Innes Center, East Anglia, UK; Jeffrey Hillman, University of Florida, Gainesville, FL. 
• While drafting these notes, Richard Stouthamer (works on Wolbachia), mentioned a new SC-like application which proposes to use develop vaccines to archaea bacteria that live in intestines of ruminants animals and produce methane suspected as contributing significantly to global warming. They mentioned vaccines, but a very obvious method of delivering the desired effect would be through a symbiotic bacteria supplied in the diet like yogurt: http://www.economist.com/science/displayStory.cfm?story_id=2724208