Attempts to isolate the citrus sudden death associated virus to analyse its involvement with the death of the plants

• Grant number: 09/04522-6
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2009
• End date: July 31, 2011
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Jorge Alberto Marques Rezende
• Grantee: Jorge Alberto Marques Rezende
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Citrus sudden death disease was first identified in the County of Comendador Gomes, State of Minas Gerais, Brazil. Since then the disease has been responsible for the death of more than 4 million trees in the Southern region of the "Triângulo Mineiro" and Northern and Northwest of the State of São Paulo. The disease affects mainly sweet orange cultivars grafted on Rangpur lime rootstock. Affected trees are characterized by pale green coloration of leaves, increased defoliation, reduction in new shoots, rot and death of a large portion of the canopy, and the characteristic development of yellow stain in the phloem of the rootstock. Although the disease has been known for more than eight years, the exact causal agent as well as its vector is still unknown. Based on the distribution of the diseased plant in the field, the symptoms, and the constant association of the Citrus tristeza virus (CTV) and a virus from the family Tymoviridae with the diseased plants, named Citrus Sudden Death associated Virus (CSDaV), it has been suggested that both pathogens might be involved with this disease. As both viruses are always present in all infected plants, the separation of both viruses is necessary to fulfill Koch's Postulates for the CSDaV. Therefore, the main purpose of the present work is to attempt to separate the CSDaV by means of mechanical inoculation into virus indicator hosts and re-introduce it into citrus plants. Once isolated, studies will be carried out in order to evaluate the involvement of the CSDaV, alone and mixed with CTV, on the citrus sudden death disease. The virus will be purified for production of polyclonal antiserum for disease diagnose by ELISA. (AU)