Various ORSV infection symptoms on ceratorhiza induction in orchid plants

Several types of orchids that are in great demand and cultivated by various groups are Phalaenopsis sp. and Dendrobium sp. Mycorrhizae are needed by orchid plants to complete their life cycle. This is because mycorrhizae are capable of symbiosis with the root system of the host plant so that the plant's capacity to absorb elements will increase. This study aims to determine the extent to which Ceratorhiza induction on Phalaenopsis amabilis and Dendrobium discolour orchids can suppress the symptoms of Odontoglossum ringspot virus (ORSV) infection. The method used in this study was a factorial completely randomized design (CRD) with 2 factors and 4 replications. The first factor is the type of orchid used, namely Phalaenopsis amabilis (A1) and Dendrobium discolour (A2), while the second factor is the type of administration of mycorrhizae, viruses, and mycorrhizal viruses. Observation of disease symptoms is done by looking at the symptoms that appear on leaves that have been infected with ORSV. The results showed that the symptoms that appeared in Phalaenopsis amabilis were in the form of mosaic, necrosis, leaf malformation, while in Dendrobium discolour were mosaic and necrotic. Ceratorhiza was not able to suppress the symptoms of disease infection because based on the results obtained; the treatment on orchids inoculated with mycorrhizae and viruses showed more severe symptoms compared to the treatment only inoculated with viruses increased response and Dendrobium discolours showed a decreased response in leaf length, width, and number. Meanwhile, in the root organ, Dendrobium discolour showed an increased response and Phalaenopsis amabilis showed a decreased response in root length and number of roots.

Exploring the Multifunctional Roles of Odontoglossum Ringspot Virus P126 in Facilitating Cymbidium Mosaic Virus Cell-to-Cell Movement during Mixed Infection

Synergistic interactions among viruses, hosts and/or transmission vectors during mixed infection can alter viral titers, symptom severity or host range. Viral suppressors of RNA silencing (VSRs) are considered one of such factors contributing to synergistic responses. Odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV), which are two of the most significant orchid viruses, exhibit synergistic symptom intensification in Phalaenopsis orchids with unilaterally enhanced CymMV movement by ORSV. In order to reveal the underlying mechanisms, we generated infectious cDNA clones of ORSV and CymMV isolated from Phalaenopsis that exerted similar unilateral synergism in both Phalaenopsis orchid and Nicotiana benthamiana. Moreover, we show that the ORSV replicase P126 is a VSR. Mutagenesis analysis revealed that mutation of the methionine in the carboxyl terminus of ORSV P126 abolished ORSV replication even though some P126 mutants preserved VSR activity, indicating that the VSR function of P126 alone is not sufficient for viral replication. Thus, P126 functions in both ORSV replication and as a VSR. Furthermore, P126 expression enhanced cell-to-cell movement and viral titers of CymMV in infected Phalaenopsis flowers and N. benthamiana leaves. Taking together, both the VSR and protein function of P126 might be prerequisites for unilaterally enhancing CymMV cell-to-cell movement by ORSV.

Variation of resistance response of orchids induced by Rhizoctonia against the infection of Odontoglossum ringspot virus (ORSV) based on percentage of disease development

Orchid is one of the largest groups of flowering plants that are in great demand by society. Besides, the various flowers with a long vase life, the price of orchids is also stable and affordable. Phalaenopsis and Dendrobium are the most popular types of orchids. To anticipate this, orchid cultivation needs to be improved. However, orchid cultivation is not always accompanied by the effort of disease prevention, particularly those caused by viruses. The virus that most infects orchids is the Odontoglossum ringspot virus (ORSV). Symptoms that appear on the leaves are chlorosis, mosaic with a pattern of lines, circles, and necrotic rings/rings. Control of viral infections can utilize organisms that are able to induce resistance, namely mycorrhizae. Mycorrhizae will penetrate into the root cortex tissue and provide nutrients for the orchid. Mycorrhizae that are quite often found are Rhizoctonia and are applied by induction to orchids. Induction was undertaken by planting orchids in Rhizoctonia inoculum until anatomically a peloton structure (solid coils) was formed on the orchid roots. The aim of this study was to study the response of orchid plants in the form of percentage incidence and intensity of the disease and the level of plant resistance to ORSV infection in Phalaenopsis amabilis and Dendrobium discolour which had been induced by Rhizoctonia. This research was conducted at the Laboratory of Botany, Biology, FMIPA, Universitas Lampung, using a factorial completely randomized design (CRD). Factor 1 was the type of orchid and factor 2 was mycorrhizal induction, virus inoculation, and a combination of both with 4 replications. The finding indicated that Phalaenopsis amabilis was more susceptible to ORSV infection than Dendrobium discolour based on a higher incidence and intensity of the disease. Mycorrhizal induction and virus inoculation (MAV) in Dendrobium discolour showed an increase of resistance response compared to Phalaenopsis amabilis.

Identification and Efforts to Control Infection Odontoglossum ringspot virus (ORSV) on Orchid

Odontoglossum ringspot virus (ORSV) is a orchid virus which infection most widely reported and has spread widely in the world, including in Indonesia. Viral infections can degrade the quality of the orchid plant so it is economically detrimental. To study a disease infection, identification is carried out first to determine the most appropriate method of control. These identification techniques include variations in infection symptoms, host range testing, testing of viral titers, observation of particle morphology, genome detection, and analysis of DNA and amino acid sequences. Efforts to control disease can be done through preventive and eradicative actions chemically, biologically, and based on artificial intelligence.

Producción de un antisuero policlonal para la detección de Cymbidium mosaic virus y Odontoglossum ringspot virus en orquídeas

Las orquídeas (familia Orchidaceae) son susceptibles a diversos factores bióticos y abióticos que afectan su desarrollo y calidad. Entre ellos, Cymbidium mosaic virus (CymMV) y Odontoglossum ringspot virus (ORSV) son los patógenos más frecuentes y de mayor importancia económica a nivel mundial. La transmisión mecánica de estos virus y la multiplicación principalmente agámica de las orquídeas hacen necesario contar con material madre libre de virus. El objetivo de este trabajo fue elaborar reactivos de diagnóstico para la detección de CymMV y ORSV. Se elaboró un antisuero policlonal contra CymMV+ORSV que se tituló 1:10000 mediante NC-ELISA. El antisuero fue procesado y se obtuvieron IgG e IgG-conjugada anti CymMV+ORSV dilución1:500 para su utilización en DAS-ELISA. La capacidad inmunodiagnóstica de esta técnica se evaluó mediante el análisis de muestras provenientes de orquídeas con síntomas característicos de infección viral, recolectadas en viveros comerciales de la ciudad de Córdoba, Argentina. La presencia de virosis se detectó en el 22 % de las muestras estudiadas y en el 75 % de los establecimientos relevados. La capacidad de estos reactivos para identificar CymMV, ORSV e infecciones mixtas en orquídeas permitirá agilizar y economizar los análisis. Esto representaría una ventaja para las detecciones a gran escala.