Nischwitz C, Srinivasan R, Sundaraj S, Mullis S W, McInnes B, Gitaitis R D
Department of Biology, Utah State University, Logan 84322.
Department of Entomology.
Plant Dis. 2012 Aug;96(8):1165-1171. doi: 10.1094/PDIS-09-11-0747-RE.
Iris yellow spot virus (IYSV) has occurred in Georgia since 2003. IYSV is transmitted by onion thrips, Thrips tabaci. During a weed survey in the Vidalia onion-growing zone (VOZ), spiny sowthistle (Sonchus asper) was identified as a host for IYSV. Spiny sowthistle is widespread in Georgia, and this presented an opportunity to study the natural spread of IYSV and assess its potential role in IYSV epidemiology. From 2007 to 2009, during the spring season, 2,011 sowthistle samples were collected from various counties within and outside the VOZ. The samples were tested for IYSV infection by enzyme-linked immunosorbent assay and confirmed by reverse-transcription polymerase chain reaction and sequencing. IYSV sequences from sowthistle were 98 to 99% identical to onion IYSV sequences from onion originated from Georgia. By the third year, IYSV-infected sowthistle plants were found in 79% of the counties in the VOZ and in 61% of the sampled counties in all directions, except to the east of the VOZ. Furthermore, thrips-mediated transmission assays confirmed that T. tabaci can efficiently transmit IYSV from onion to sowthistle. Sowthistle also supported T. tabaci survival and reproduction. These findings demonstrate that sowthistle plants can serve as an IYSV inoculum source and as a thrips reservoir.
自2003年以来，鸢尾黄斑病毒（IYSV）已在佐治亚州出现。IYSV由烟蓟马传播。在维达利亚洋葱种植区（VOZ）的一次杂草调查中，刺儿菜被确定为IYSV的宿主。刺儿菜在佐治亚州广泛分布，这为研究IYSV的自然传播及其在IYSV流行病学中的潜在作用提供了机会。2007年至2009年春季，从VOZ内外的不同县采集了2011份刺儿菜样本。通过酶联免疫吸附测定法检测样本是否感染IYSV，并通过逆转录聚合酶链反应和测序进行确认。刺儿菜的IYSV序列与源自佐治亚州洋葱的洋葱IYSV序列有98%至99%的同源性。到第三年，在VOZ 79%的县以及VOZ以东以外各个方向61%的采样县发现了感染IYSV的刺儿菜植株。此外，蓟马介导的传播试验证实，烟蓟马能够有效地将IYSV从洋葱传播到刺儿菜。刺儿菜也有利于烟蓟马的生存和繁殖。这些发现表明，刺儿菜植株可以作为IYSV的接种源和蓟马的宿主。
