2 Apr 2004 16:00
Unit:
Wageningen University
Location:
Aula (gebouw 362), Gen. Foulkesweg 1, Wageningen
Promotor:
prof.dr. R.W. Goldbach (Virology)
Co Promotor:
dr. D. Peters
The objective of this study was to analyse the effect of thrips (F. occidentalis) resistance in pepper (Capsicum) on the spread of Tomato spotted wilt virus (TSWV). Results demonstrate that the rate of primary TSWV-infection is effectively limited in a thrips-resistant (TR) pepper crop compared to a thrips-susceptible (TS) crop, and that this is based on a decreased preference of thrips for TR plants. Secondary TSWV-infections were effectively restricted in the TR pepper crop and this is based on a greatly reduced thrips population built-up.
The effect of thrips resistance on the spread of TSWV was also analysed in a virus-resistant genotype. TSWV-resistant plants respond with a hypersensitive reaction after infection with TSWV, resulting in necrotic local lesions on leaves and fruits. Under the same infection pressure, fewer local lesions were found in the thrips-resistant accession PI 152225 than in the thrips-susceptible PI 159236 accession, indicating a synergistic effect of thrips- and virus resistance.
Studies presented in the last part of the thesis show mutual benefits for F. occidentalis and TSWV from the attraction to virus-infected plants. Attraction resulted in more offspring on these plants and thereby enhancing the chance for virus transmission. Besides, thrips developed significantly faster on TSWV-infected plants than on non-infected plants. It was demonstrated that volatiles released from TSWV-infected plants may be involved in the attraction of thrips to TSWV-infected plants.