Search

Bermudagrass decline (BD) is a destructive root rot disease of hybrid bermudagrass putting greens in the southeastern United States. Previous studies reported a single ectotrophic root-infecting (ERI) fungus, Gaeumannomyces graminis, associated with BD. Recently, three novel ERI fungi, Gaeumannomyces sp., Magnaporthiopsis cynodontis, and Candidacolonium cynodontis, have also been associated with BD. Current diagnostic methods for identification can be inconclusive and inaccurate for distinguishing these ERI fungal species. Here, we present the development and application of novel real-time PCR assays designed to detect four selected ERI fungi associated with BD. The distribution of these ERI fungi in hybrid bermudagrass samples collected from putting greens and fairways throughout the southeastern United States was also assessed. In addition, we established a reliable and rapid protocol to simultaneously detect these selected fungi directly from bermudagrass root tissue. The limit of detection for each assay was as low as 1 pg/µl of DNA per reaction, proving the sensitivity of the method to detect low quantities of fungal DNA when present in bermudagrass roots. The presence of the selected ERI fungi was detected in 36 of 37 bermudagrass root samples, with one fungus having a wider distribution among the samples tested and two fungi with greater DNA quantities when compared with the bermudagrass roots. The novel assays provide a reliable method for accurate detection of the four selected ERI fungi. The acute sensitivity of each assay makes it a viable tool for early detection of ERI fungi in hybrid bermudagrass roots.

Made available in DSpace on 2019-10-04T12:35:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-19 FEDER - COMPETE Program Fundacao para a Ciencia e Tecnologia Project CMDT: Past and present population genetics of the vector Aedes aegypti: a tool for dengue control policies FCT Historically known as the yellow fever mosquito, Aedes aegypti invaded Madeira Island in 2005 and was the vector of the island's first dengue outbreak in 2012. We have studied genetic variation at 16 microsatellites and two mitochondrial DNA genes in temporal samples of Madeira Island, in order to assess the origin of the invasion and the population structure of this mosquito vector. Our results indicated at least two independent colonization events occurred on the island, both having a South American source population. In both scenarios, Venezuela was the most probable origin of these introductions, a result that is in accordance with the socioeconomic relations between this country and Madeira Island. Once introduced, Ae. aegypti has rapidly expanded along the southern coast of the island and reached a maximum effective population size (N-e) in 2012, coincident with the dengue epidemic. After the outbreak, there was a 10-fold reduction in N-e estimates, possibly reflecting the impact of community-based vector control measures implemented during the outbreak. These findings have implications for mosquito surveillance not only for Madeira Island, but also for other European regions where Aedes mosquitoes are expanding. Univ Nova Lisboa, Inst Higiene & Med Trop, Global Hlth & Trop Med, Lisbon, Portugal Univ Estadual Paulista, Inst Biociencias, Dept Parasitol, Botucatu, SP, Brazil Museum Nat Hist Funchal, RAM, Madeira, Portugal Univ Cent Venezuela, Inst Med Trop, Secc Entomol Med, Caracas, Venezuela IP RAM, Dept Saude Planeamento & Adm Geral, Inst Adm Saude & Assuntos Sociais, Funchal, Madeira, Portugal Madeira Reg Govt, Funchal, Madeira, Portugal Hlth & Social Affairs, Funchal, Madeira, Portugal Univ Estadual Paulista, Inst Biociencias, Dept Parasitol, Botucatu, SP, Brazil FEDER - COMPETE Program: PTDC/SAU-EPI/115853/2009 Fundacao para a Ciencia e Tecnologia: PTDC/SAU-EPI/115853/2009 Project CMDT: Past and present population genetics of the vector Aedes aegypti: a tool for dengue control policies: Pest-OE/SAU/LA0018/2011 FCT: SFRH/BD/98873/2013 FCT: SFRH/BPD/72532/2010 : GHTM-UID/Multi/04413/2013

Plant pathogens are constantly emerging and spreading into new areas and there are often limited postdiagnosis treatment options for infection, making surveillance key to their control. Here we present results from a study testing the efficacy of a portable nanopore-based massively parallel sequencing (MPS) technology for use in the detection of diverse plant pathogens in selected samples. The Oxford MinION device was coupled with whole transcriptome amplification (WTA) to sequence the metatranscriptome of plant and insect tissues infected with either Candidatus Liberibacter asiaticus or plum pox virus. Results showed that this methodology is useful for detecting unsuspected viral and bacterial pathogens in plant and insect tissues. The percentage of generated reads assigned to plum pox virus was 95% from infected tissue and 3% from the viruliferous insect, Myzus persicae. Diaphorina citri sequencing led to 22% of the reads mapping as Ca. L. asiaticus. Plum pox virus and Ca. L. asiaticus were detected in both tissue and insect samples near the beginning of each sequencing run, demonstrating the capability of this methodology to obtain results rapidly. This approach also proved the capability of this system to determine the major components of the insect vector’s microbiome and the specific strain of small-genome, high-titer pathogens.