Analysis of I ris yellow spot virus replication in vector and non‐vector thrips species

• Published in: Plant pathology 2013-12, Vol.62 (6), p.1407-1414
• Main Authors: Birithia, R., Subramanian, S., Pappu, H. R., Muthomi, J., Narla, R. D.
• Format: Article
• Language: English
• ISSN: 0032-0862; 1365-3059
• DOI: 10.1111/ppa.12057

Iris yellow spot virus ( IYSV , genus T ospovirus ) is a viral disease of bulb and seed onion crops and is transmitted by T hrips tabaci . Foliage damage of up to 75% has been reported in Kenya and Uganda. In this study, the rate of IYSV replication in the larva, pupa and adult stages of T . tabaci and other non‐vector thrips species and colour forms such as F rankliniella occidentalis, F . schultzei (dark) and F . schultzei (pale) was evaluated by monitoring relative levels of nucleocapsid ( N ) and non‐structural ( NS s) proteins using N ‐ and NS s‐specific antibodies. The effect of IYSV replication on mortality of thrips was also determined. N protein levels increased in all three stages of IYSV ‐fed T . tabaci , indicating replication of IYSV . In IYSV ‐fed non‐vector thrips, the increase of N protein levels in the larval stage was lower than IYSV ‐fed T . tabaci but higher than their healthy counterparts. The N protein levels did not increase at pupal and adult stages. NS s protein was not detected in first instar of either vector or non‐vector thrips species. After a 4 h post‐acquisition period, a significant increase in NS s proteins was only observed in IYSV ‐fed T . tabaci , clearly differentiating vectors and non‐vectors of IYSV . IYSV replication did not influence the survival of the vector thrips species, T . tabaci populations or the non‐vector thrips species. This study indicates the effectiveness of monitoring non‐structural proteins such as NS s, compared to nucleocapsid proteins, for differentiating vectors and non‐vectors of IYSV .