Department of Plant and Environmental Protection Sciences, University of Hawaii, 3050 Maile Way, Gilmore Hall #310, Honolulu, HI 96822, USA.
J Econ Entomol. 2013 Feb;106(1):16-24. doi: 10.1603/ec12056.
Maize chlorotic mottle virus (MCMV) (Tombusviridae: Machlomovirus) has been recorded in Hawaii (Kauai Island) since the early 1990s and has since become one of the most widespread corn viruses in the Hawaiian Islands. In the United States Mainland, MCMV has been reported to be transmitted by six different species of chrysomelid beetles, including the western corn rootworm, Diabrotica virgifera virgifera LeConte. However, none of these beetle species have been reported in Hawaii where the corn thrips, Frankliniella williamsi Hood (Thysanoptera: Thripidae) has been identified to be the main vector. In this study, we developed leaf disk transmission assays and real time reverse transcription-polymerase chain reaction to examine the mode of MCMV transmission by the corn thrips. We showed that thrips transmitted the virus with no evidence for latent periods. Both larvae and adults transmitted the virus for up to 6 d after acquisition, with decreasing rates of transmission as time progressed. There was no evidence that adult thrips that acquired the virus as larvae were competent vectors. Real time reverse-transcription polomerase chain reaction assays showed that viral load was depleted from the vector's body after thrips had access to healthy plant tissue. Depletion of viral load was also observed when thrips matured from larvae to adults. Thrips were able to transmit MCMV after acquisition and inoculation access periods of 3 h. However, transmission efficiency increased with longer acquisition and inoculation access periods. Taken altogether our data suggests that corn thrips transmit MCMV in a semipersistent manner. To our knowledge, this is the first work reporting evidence of a plant virus transmitted semipersistently by thrips.
玉米褪绿斑驳病毒（MCMV）（Tombusviridae：Machlomovirus）自 20 世纪 90 年代初在夏威夷（考艾岛）被记录以来，已成为夏威夷群岛最广泛传播的玉米病毒之一。在美国本土，MCMV 已被报道由 6 种不同的叶甲科甲虫传播，包括西部玉米根叶甲，Diabrotica virgifera virgifera LeConte。然而，这些甲虫在夏威夷均未被报道，在夏威夷，玉米蓟马，Frankliniella williamsi Hood（缨翅目：蓟马科）已被确定为主要传播媒介。在这项研究中，我们开发了叶片圆盘传播测定法和实时逆转录聚合酶链反应，以检查玉米蓟马传播 MCMV 的方式。我们表明，蓟马在没有潜伏期的情况下传播病毒。幼虫和成虫在获得病毒后最多可传播 6 天，随着时间的推移，传播率逐渐降低。没有证据表明作为幼虫获得病毒的成年蓟马是有能力的传播媒介。实时逆转录聚合酶链反应测定表明，在蓟马接触健康植物组织后，病毒载量从载体体内耗尽。当蓟马从幼虫成熟为成虫时，也观察到病毒载量的耗竭。蓟马在获得和接种 3 小时后即可传播 MCMV。然而，随着获得和接种访问期的延长，传播效率增加。总的来说，我们的数据表明，玉米蓟马以半持久的方式传播 MCMV。据我们所知，这是首次报道由蓟马半持久传播的植物病毒。
