Background/context:

This project focuses on Tospoviruses, which cause increasingly important disease problems in Australia and worldwide, and diagnostics for quarantine viruses which are collected, intercepted or targeted by the Australian quarantine. Tospoviruses are of increasing economic importance worldwide, and their thrips’ vectors are becoming increasingly resistant to insecticides. Two important vector species, western flower thrips and melon thrips, have recently been found in Australia, and their distribution is increasing. Chemical control of vectors to contain the disease is not a sustainable practice. Only the use of resistant cultivars is feasible for long-term control. Knowledge of tospovirus diversity and actual vector species is a necessary precursor to control.

 Aim:

The aims of the tospovirus research were: to survey crops and weeds, to identify and characterize new tospovirus species, to determine abundance and distribution of thrips species and identify vector species, to identify tospovirus resistance in Capsicum germplasm, and to prepare antisera for diagnostic assays The aims of the quarantine aspects of this project were to characterize the new banana bunchy top virus (BBTV) strain and develop assays, to characterize the new Passiflora virus and develop assays, to identify viruses from Northern Australian Quarantine Strategy surveys, to consolidate the reference collection of virus isolates, diagnostic antisera and probes, and to validate detection assays for target pathogens. Major Outcomes:

Major Outcomes:

• A new virus, Capsicum chlorosis virus (CaCV), discovered in tomato, capsicum, hoya and peanut, and characterized

• Stachytarpheta (snakeweed) important in the epidemiology of Tomato spotted wilt virus (TSWV) in north Queensland

• Ageratum conizoides identified as an important weed host of CaCV

• TSWV transmitted by T. palmi, F. schultzii and F. occidentalis

• CaCV transmitted by T. palmi, F. schultzii, but not F. occidentalis

• Resistance breaking strain of TSWV found in capsicum in SA

• Independent sources of resistance to CaCV and TSWV found in Capsicum germplasm

• TSWV and CaCV nucleocapsid genes cloned for protein expression and antiserum to CaCV produced

• New Babuvirus species identified from banana and abaca in South-east Asia, coat protein cloned for protein expression and antiserum produced

• New Potyvirus (Passiflora virus Y), Hibiscus S tobamovirus, Tomato leafcurl virus and Rice tungro bacilliform virus identified through NAQS surveys

• PEQ interceptions include Peanut stripe virus, Euphorbia potyvirus, sweet potato reovirus, unidentified Hoya virus

For more information contact:

Dr John Thomas
Department of Primary Industries and Fisheries
Phone: +61 (0)7 3896 9371
Email: John.Thomas@dpi.qld.gov.au