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.

Ploidy level and caffeine content in leaves of Coffea

Several species of Coffea and varieties of C. arabica differing in chromosome number had their caffeine content determined in the leaves. For Coffea arabica var. "Angustifolia", var. "Caturra" and var. "Icatu", it was observed caffeine decrease from the haploid (2n = 22) to tetraploid leaves (2n = 44). Caffeine in the tetraploid "Angustifolia" was decreased by 50% when compared to the haploid. Caffeine reduction was also observed in leaves of C. canephora var. "Kouilou" as chromosome number was increased (2n = 22 ® 2n = 44). In this case, caffeine in the leaves of the diploid genotype was close to 4 times higher than in the tetraploid. On the other hand it was observed an increase of the alkaloid when the chromosome number was doubled in the C. canephora var. "Robusta".

Variedades e espécies de café (Coffea) que diferem quanto ao número de cromossomos tiveram o conteúdo de cafeína determinado em suas folhas. Para as variedades "Angustifolia", "Caturra" e "Icatu" de Coffea arabica foi observada redução no teor de cafeína de folhas haplóides (2n = 22) em relação a tetraplóides (2n = 44). Cafeína na forma tetraplóide da var. "Angustifolia" foi reduzida em 50% quando comparada com a forma haplóide. Redução de cafeína também foi observada em folhas de C. canephora var. "Kouilou" quando o número de cromossomos aumentou (2n = 22 ® 2n = 44). Neste caso, a cafeína nas folhas do genótipo diplóide foi cerca de quatro vezes maior que no tetraplóide. Por outro lado, foi observado aumento desse alcalóide quando o número de cromossomos foi duplicado em C. canephora var. "Robusta".

Ploidy level and caffeine content in leaves of Coffea

Several species of Coffea and varieties of C. arabica differing in chromosome number had their caffeine content determined in the leaves. For Coffea arabica var. "Angustifolia", var. "Caturra" and var. "Icatu", it was observed caffeine decrease from the haploid (2n = 22) to tetraploid leaves (2n = 44). Caffeine in the tetraploid "Angustifolia" was decreased by 50% when compared to the haploid. Caffeine reduction was also observed in leaves of C. canephora var. "Kouilou" as chromosome number was increased (2n = 22 ® 2n = 44). In this case, caffeine in the leaves of the diploid genotype was close to 4 times higher than in the tetraploid. On the other hand it was observed an increase of the alkaloid when the chromosome number was doubled in the C. canephora var. "Robusta".

Variedades e espécies de café (Coffea) que diferem quanto ao número de cromossomos tiveram o conteúdo de cafeína determinado em suas folhas. Para as variedades "Angustifolia", "Caturra" e "Icatu" de Coffea arabica foi observada redução no teor de cafeína de folhas haplóides (2n = 22) em relação a tetraplóides (2n = 44). Cafeína na forma tetraplóide da var. "Angustifolia" foi reduzida em 50% quando comparada com a forma haplóide. Redução de cafeína também foi observada em folhas de C. canephora var. "Kouilou" quando o número de cromossomos aumentou (2n = 22 ® 2n = 44). Neste caso, a cafeína nas folhas do genótipo diplóide foi cerca de quatro vezes maior que no tetraplóide. Por outro lado, foi observado aumento desse alcalóide quando o número de cromossomos foi duplicado em C. canephora var. "Robusta".