Britt Kellee, Gebben Samantha, Levy Amit, Al Rwahnih Maher, Batuman Ozgur
Department of Plant Pathology, Southwest Florida Research and Education Center, University of Florida, Immokalee, FL, United States.
Department of Plant Pathology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States.
Front Plant Sci. 2020 Jan 17;10:1687. doi: 10.3389/fpls.2019.01687. eCollection 2019.
The plant pathogenic bacterium Liberibacter asiaticus (Las), the causal agent of the citrus disease Huanglongbing (HLB), and its insect vector, the Asian citrus psyllid (ACP; ), have been devastating the Florida citrus industry. To restore the competitive production presence of Florida in the worldwide citrus market, effective and sustainable control of HLB and the ACP needs to be identified. As alternatives for resistance-inducing insecticides, viruses are currently being considered for biological control of the ACP. To identify possible biological control candidates, we conducted one of the most comprehensive surveys of natural ACP populations in major citrus production regions spanning 21 counties in Florida. By optimizing PCRs and RT-PCRs, we were able to successfully detect and monitor the prevalence of five previously identified ACP-associated RNA and DNA viruses throughout Florida citrus groves, which include: (DcACV), (DcFLV), (DcDNV) (DcRV), and - (DcPLV). Adult and nymph ACP populations from 21 of Florida's major citrus-producing counties were collected each month during approximately 18 consecutive months. RNA extracts used for these viral screens were also regionally combined and subjected to High Throughput Sequencing (HTS) to reveal a more comprehensive picture of known and unknown viruses in Florida ACP populations. We discovered that DcACV was the most prevalent ACP-associated virus throughout nymph and adult ACP populations in Florida, detected in more than 60% of all samples tested, followed by DcPLV and DcFLV. HTS allowed us to identify a novel ACP-associated reo-like virus and a picorna-like virus. The putative reo-like virus, tentatively named cimodo-like virus, was later surveyed and detected back in seasonal adult and nymph ACP samples collected in Florida during this study. HTS generated data also revealed that the most abundant virus in Florida ACP populations was (CTV), which is not an ACP-associated virus, suggesting persistent presence of CTV infection in citrus throughout Florida groves. Collectively, information obtained from our study may be able to help guide the direction of biotechnological pest control efforts involving a number of viruses that were detected for the first time in Florida ACP populations, including two newly identified ACP-associated viruses.
植物病原菌亚洲韧皮杆菌（Las）是柑橘黄龙病（HLB）的致病因子，其昆虫传播媒介亚洲柑橘木虱（ACP）给佛罗里达州的柑橘产业带来了毁灭性打击。为恢复佛罗里达州在全球柑橘市场上具有竞争力的生产地位，需要确定对HLB和ACP进行有效且可持续控制的方法。作为诱导抗性杀虫剂的替代物，目前正在考虑利用病毒对ACP进行生物防治。为了确定可能的生物防治候选病毒，我们对佛罗里达州21个县的主要柑橘产区的自然ACP种群进行了最全面的调查之一。通过优化聚合酶链反应（PCR）和逆转录聚合酶链反应（RT-PCR），我们能够成功检测和监测佛罗里达州柑橘园中五种先前已确定的与ACP相关的RNA和DNA病毒的流行情况，这些病毒包括：柑橘木虱伴随病毒（DcACV）、柑橘木虱佛罗里达病毒（DcFLV）、柑橘木虱双链DNA病毒（DcDNV）、柑橘木虱环病毒（DcRV）和柑橘木虱潜隐病毒（DcPLV）。在大约连续18个月的时间里，每月从佛罗里达州21个主要柑橘生产县采集成年和若虫期的ACP种群。用于这些病毒筛查的RNA提取物也按区域进行合并，并进行高通量测序（HTS），以更全面地了解佛罗里达州ACP种群中已知和未知病毒的情况。我们发现，在佛罗里达州若虫和成年ACP种群中，DcACV是最普遍的与ACP相关的病毒，在所有检测样本中，超过60%的样本检测到该病毒，其次是DcPLV和DcFLV。高通量测序使我们能够鉴定出一种新型的与ACP相关的呼肠孤样病毒和一种小RNA病毒样病毒。这种推定的呼肠孤样病毒，暂命名为柑橘木虱西莫多样病毒，后来在本研究期间对佛罗里达州采集的季节性成年和若虫期ACP样本进行调查时再次检测到。高通量测序产生的数据还显示，佛罗里达州ACP种群中最丰富的病毒是柑橘衰退病毒（CTV），它不是一种与ACP相关的病毒，这表明CTV感染在佛罗里达州所有柑橘园中持续存在。总体而言，我们研究获得的信息可能有助于指导生物技术害虫防治工作的方向，这些工作涉及在佛罗里达州ACP种群中首次检测到的多种病毒，包括两种新鉴定的与ACP相关的病毒。
