Natural infection of several Coffea species and hybrids and Psilanthus ebracteolatus by the coffee ringspot virus (CoRSV)

Coffee ringspot is a minor coffee disease caused by the nuclear type of Brevipalpus mite-transmitted virus, Coffee ringspot virus (CoRSV). Recently outbreaks of the disease in some growing regions of the state of Minas Gerais, Brazil, were registered with qualitative and quantitative yield losses. Coffea arabica was the only species registered as natural host. A survey was made on a germplasm collection of Coffea and related species kept at the Centro de Café "Alcides Carvalho", Instituto Agronômico, Campinas, state of São Paulo (SP), Brazil, to assess natural susceptibility of Coffee species, other than C. arabica and some interspecific hybrids of Coffea as well as other non-Coffea plant species to the Coffee ringspot virus (CoRSV). The following plants were found with ringspot symptoms on their leaves and/or fruits besides C. arabica L.: C. kapakata (IAC 4511), C. dewevrei cv. Excelsa, C. canephora cv. Robusta, hybrid derivative of the C. arabica × C. racemosa (IAC1195-5-6-2), C. arabica × C. dewerei (Piatã IAC 387), Híbrido de Timor CIFC 832/1 (derivative from a natural crossing between C. arabica × C. canephora) and C. racemosa. Also Psilanthus ebracteolatus, a species close to the genus Coffee was also found with ringspot lesions on their leaves. All these plants were also found infested by Brevipalpus mites identified as B. phoenicis. Infection of these plants by CoRSV was confirmed by the observation of characteristic cytopathic effects in the tissues of the lesion and by RT-PCR using a pair of primer specific for CoRSV. Only with C. racemosa RT-PCR failed to amplify the CoRSV genome. The susceptibility of P. ebracteolatus to CoRSV adds new dimension regarding its controversial taxonomic position.

Natural infection of several Coffea species and hybrids and Psilanthus ebracteolatus by the coffee ringspot virus (CoRSV)

Coffee ringspot is a minor coffee disease caused by the nuclear type of Brevipalpus mite-transmitted virus, Coffee ringspot virus (CoRSV). Recently outbreaks of the disease in some growing regions of the state of Minas Gerais, Brazil, were registered with qualitative and quantitative yield losses. Coffea arabica was the only species registered as natural host. A survey was made on a germplasm collection of Coffea and related species kept at the Centro de Café "Alcides Carvalho", Instituto Agronômico, Campinas, state of São Paulo (SP), Brazil, to assess natural susceptibility of Coffee species, other than C. arabica and some interspecific hybrids of Coffea as well as other non-Coffea plant species to the Coffee ringspot virus (CoRSV). The following plants were found with ringspot symptoms on their leaves and/or fruits besides C. arabica L.: C. kapakata (IAC 4511), C. dewevrei cv. Excelsa, C. canephora cv. Robusta, hybrid derivative of the C. arabica × C. racemosa (IAC1195-5-6-2), C. arabica × C. dewerei (Piatã IAC 387), Híbrido de Timor CIFC 832/1 (derivative from a natural crossing between C. arabica × C. canephora) and C. racemosa. Also Psilanthus ebracteolatus, a species close to the genus Coffee was also found with ringspot lesions on their leaves. All these plants were also found infested by Brevipalpus mites identified as B. phoenicis. Infection of these plants by CoRSV was confirmed by the observation of characteristic cytopathic effects in the tissues of the lesion and by RT-PCR using a pair of primer specific for CoRSV. Only with C. racemosa RT-PCR failed to amplify the CoRSV genome. The susceptibility of P. ebracteolatus to CoRSV adds new dimension regarding its controversial taxonomic position.

Chlorotic spots on Clerodendrum, a disease caused by a nuclear type of Brevipalpus (Acari:Tenuipalpidae) transmitted virus

Chlorotic spots have been observed in plants of Clerodendrum x speciosum growing in residential gardens and parks in Piracicaba, SP, Brazil. Thin sections of diseased tissues revealed characteristic cytopathic effects of the nuclear type of the Brevipalpus (Acari: Tenuipalpidae) mite-transmitted viruses (BTrV). Brevipalpus mites, identified as B. phoenicis, infesting symptomatic C. x speciosum plants transmitted the pathogen to healthy C. x speciosum and to C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi and Tetragonia expansa causing chlorotic spots on their leaves. Mechanical inoculation using leaf extracts from infected C. x speciosum resulted in chlorotic spots on inoculated C. x speciosum, Chenopodium quinoa, C. amaranticolor, G. globosa, H. cannabinus, H. coccineus and T. expansa leaves. C. amaranticolor and C. quinoa kept at 28 - 30°C became systemically infected. The same cytopathic effects caused by the nuclear type of BTrV were seen in tissues from all infected test plants by electron microscopy. The virus was purified from systemically infected leaves of C. amaranticolor and C. quinoa. A polyclonal antiserum obtained from an immunized rabbit presented a strong reaction with the homologous antigen in ELISA tests. The results suggest that this chlorotic spot disease of C. x speciosum is caused by a new species of the nuclear type of BTrV, tentatively named Clerodendrum chlorotic spot virus (ClCSV).

Manchas cloróticas e necróticas foram observadas em folhas de várias plantas de coração-sangrento (Clerodendrum x speciosum) cultivadas em parques e jardins em Piracicaba, SP, associadas à infestação pelo ácaro tenuipalpídeo Brevipalpus phoenicis. Exames preliminares de secções de tecido das manchas cloróticas ao microscópio eletrônico revelaram a ocorrência de efeitos citopáticos característicos dos induzidos pelos vírus do tipo nuclear, transmitido por ácaros Brevipalpus (VTB). Brevipalpus phoenicis coletados de C. x speciosum sintomático e transferidos para plantas sadias de C. x speciosum reproduziram as lesões. O ácaro também transmitiu o patógeno para C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi e Tetragonia expansa, as quais exibiram manchas cloróticas e/ou necróticas. O vírus também foi transmitido mecanicamente para Chenopodium amaranticolor, C. quinoa, G. globosa, H. cannabinus, H. coccineus e T. expansa, além de C. x speciosum. Plantas de C. amaranticolor e C. quinoa mantidas a 28 - 30ºC desenvolveram infecção sistêmica. Em todos os tecidos sintomáticos das plantas-teste inoculadas, examinados ao microscópio eletrônico, foram encontrados efeitos citopáticos do tipo nuclear causado por VTB. O vírus foi purificado a partir de folhas com infecção sistêmica de C. amaranticolor e C. quinoa. Injeções de preparações purificadas em coelho geraram um anti-soro policlonal que reagiu especificamente com o antígeno homólogo em teste de ELISA. As evidências obtidas indicam que as manchas cloróticas do Clerodendrum estão associadas a um VTB do tipo nuclear, tentativamente denominado de vírus da mancha clorótica do Clerodendrum (Clerodendrum chlorotic spot virus- ClCSV).

Chlorotic spots on Clerodendrum, a disease caused by a nuclear type of Brevipalpus (Acari:Tenuipalpidae) transmitted virus

Chlorotic spots have been observed in plants of Clerodendrum x speciosum growing in residential gardens and parks in Piracicaba, SP, Brazil. Thin sections of diseased tissues revealed characteristic cytopathic effects of the nuclear type of the Brevipalpus (Acari: Tenuipalpidae) mite-transmitted viruses (BTrV). Brevipalpus mites, identified as B. phoenicis, infesting symptomatic C. x speciosum plants transmitted the pathogen to healthy C. x speciosum and to C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi and Tetragonia expansa causing chlorotic spots on their leaves. Mechanical inoculation using leaf extracts from infected C. x speciosum resulted in chlorotic spots on inoculated C. x speciosum, Chenopodium quinoa, C. amaranticolor, G. globosa, H. cannabinus, H. coccineus and T. expansa leaves. C. amaranticolor and C. quinoa kept at 28 - 30°C became systemically infected. The same cytopathic effects caused by the nuclear type of BTrV were seen in tissues from all infected test plants by electron microscopy. The virus was purified from systemically infected leaves of C. amaranticolor and C. quinoa. A polyclonal antiserum obtained from an immunized rabbit presented a strong reaction with the homologous antigen in ELISA tests. The results suggest that this chlorotic spot disease of C. x speciosum is caused by a new species of the nuclear type of BTrV, tentatively named Clerodendrum chlorotic spot virus (ClCSV).

Manchas cloróticas e necróticas foram observadas em folhas de várias plantas de coração-sangrento (Clerodendrum x speciosum) cultivadas em parques e jardins em Piracicaba, SP, associadas à infestação pelo ácaro tenuipalpídeo Brevipalpus phoenicis. Exames preliminares de secções de tecido das manchas cloróticas ao microscópio eletrônico revelaram a ocorrência de efeitos citopáticos característicos dos induzidos pelos vírus do tipo nuclear, transmitido por ácaros Brevipalpus (VTB). Brevipalpus phoenicis coletados de C. x speciosum sintomático e transferidos para plantas sadias de C. x speciosum reproduziram as lesões. O ácaro também transmitiu o patógeno para C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi e Tetragonia expansa, as quais exibiram manchas cloróticas e/ou necróticas. O vírus também foi transmitido mecanicamente para Chenopodium amaranticolor, C. quinoa, G. globosa, H. cannabinus, H. coccineus e T. expansa, além de C. x speciosum. Plantas de C. amaranticolor e C. quinoa mantidas a 28 - 30ºC desenvolveram infecção sistêmica. Em todos os tecidos sintomáticos das plantas-teste inoculadas, examinados ao microscópio eletrônico, foram encontrados efeitos citopáticos do tipo nuclear causado por VTB. O vírus foi purificado a partir de folhas com infecção sistêmica de C. amaranticolor e C. quinoa. Injeções de preparações purificadas em coelho geraram um anti-soro policlonal que reagiu especificamente com o antígeno homólogo em teste de ELISA. As evidências obtidas indicam que as manchas cloróticas do Clerodendrum estão associadas a um VTB do tipo nuclear, tentativamente denominado de vírus da mancha clorótica do Clerodendrum (Clerodendrum chlorotic spot virus- ClCSV).