Marchant Wendy G, Brown Judith K, Gautam Saurabh, Ghosh Saptarshi, Simmons Alvin M, Srinivasan Rajagopalbabu
Department of Entomology, University of Georgia, Griffin, GA 30223, USA.
School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA.
Insects. 2024 Sep 30;15(10):760. doi: 10.3390/insects15100760.
Tomato yellow leaf curl virus (TYLCV) causes significant yield loss in tomato production in the southeastern United States and elsewhere. TYLCV is transmitted by the whitefly cryptic species in a persistent, circulative, and non-propagative manner. Unexpectedly, transovarial and sexual transmission of TYLCV has been reported for one strain from Israel. In this study, the potential contribution of the B cryptic species transovarial and sexual transmission of TYLCV (Israel strain, Georgia variant, Georgia, USA) to reoccurring outbreaks was investigated by conducting whitefly-TYLCV transmission assays and virus DNA detection using end point PCR, DNA quantitation via real-time PCR, and virion detection by immunocapture PCR. TYLCV DNA was detectable in four, two, and two percent of first-generation fourth-instar nymphs, first-generation adults, and second-generation adults, respectively, following transovarial acquisition. Post-mating between viruliferous counterparts, the virus's DNA was detected in four percent of males and undetectable in females. The accumulation of TYLCV DNA in whiteflies from the transovarial and/or sexual experiments was substantially lower (100 to 1000-fold) compared with whitefly adults allowed a 48-hr acquisition-access period on plants infected with TYLCV. Despite the detection of TYLCV DNA in whiteflies from the transovarial and/or mating experiments, the virions were undetectable by immunocapture PCR-a technique specifically designed to detect virions. Furthermore, tomato test plants exposed to whitefly adults that presumably acquired TYLCV transovarially or through mating remained free of detectable TYLCV DNA. Collectively, the extremely low levels of TYLCV DNA and complete absence of virions detected in whiteflies and the inability of the cryptic species B to transmit TYLCV to test tomato plants following transovarial and mating acquisition indicate that neither transovarial nor sexual transmission of TYLCV are probable or epidemiologically relevant for TYLCV persistence in this pathosystem.
番茄黄化曲叶病毒（TYLCV）在美国东南部及其他地区的番茄生产中导致了严重的产量损失。TYLCV由粉虱隐种以持久、循环且非增殖的方式传播。出乎意料的是，已报道来自以色列的一个毒株可经卵和有性传播TYLCV。在本研究中，通过进行粉虱 - TYLCV传播试验以及使用终点PCR进行病毒DNA检测、通过实时PCR进行DNA定量以及通过免疫捕获PCR进行病毒粒子检测，研究了粉虱隐种B经卵和有性传播TYLCV（以色列毒株，佐治亚变种，美国佐治亚州）对反复爆发的潜在贡献。经卵获取后，分别在4%、2%和2%的第一代四龄若虫、第一代成虫和第二代成虫中检测到TYLCV DNA。带毒个体交配后，在4%的雄虫中检测到病毒DNA，而雌虫中未检测到。与在感染TYLCV的植株上有48小时获毒取食期的粉虱成虫相比，经卵和/或有性试验的粉虱中TYLCV DNA的积累量显著更低（100至1000倍）。尽管在经卵和/或交配试验的粉虱中检测到了TYLCV DNA，但通过专门设计用于检测病毒粒子的免疫捕获PCR未检测到病毒粒子。此外，接触可能经卵或通过交配获得TYLCV的粉虱成虫的番茄试验植株未检测到可检测到的TYLCV DNA。总体而言，在粉虱中检测到的TYLCV DNA水平极低且未检测到病毒粒子，以及隐种B在经卵和交配获取后无法将TYLCV传播给试验番茄植株，表明TYLCV的经卵传播和有性传播对于该病害系统中TYLCV的持续存在不太可能发生，在流行病学上也不相关。
