Sequences of the coat protein gene from brazilian isolates of Papaya ringspot virus

Abstract

Papaya ringspot virus (PRSV) is the causal agent of the main papaya (Carica papaya) disease in the world. Brazil is currently the world's main papaya grower, responsible for about 40% of the worldwide production. Resistance to PRSV on transgenic plants expressing the PRSV coat protein (cp) gene was shown to be dependent on the sequence homology between the cp transgene expressed in the plant genome and the cp gene from the incoming virus, in an isolate-specific fashion. Therefore, knowledge of the degree of homology among the cp genes from distinct PRSV isolates which are present in a given area is important to guide the development of transgenic papaya for the control of PRSV in that area. The objective of the present study was to assess the degree of homology among the PRSV cp genes of several Brazilian isolates of this virus. Papaya and PRSV are present in many different ecosystems within Brazil. Twelve PRSV isolates, collected in eight different states from four different geographic regions, were used in this study. The sequences of the cp gene from these isolates were compared among themselves and to the gene used to generate transgenic papaya for Brazil. An average degree of homology of 97.3% at the nucleotide sequence was found among the Brazilian isolates. When compared to 27 isolates from outside Brazil in a homology tree, the Brazilian isolates were clustered with Australian, Hawaiian, and Central and North American isolates, with an average degree of homology of 90.7% among them.

First report and molecular characterization of an isolate of papaya ringspot virus (PRSV-W) detected in pumpkin in Cuba

“…These differences in the sizes of the CP fragments are due to the insertion of two amino acids in the Brazilian isolates PRSV-W-1, PRSV-W-2, and PRSV-W-3, as previously reported by Inoue Nagata et al (2007), and a deletion of two amino acids in the Cuban isolate IBP-SDo (PORTAL et al 2006). These insertions and deletions in the N-terminal CP region suggest that this region is highly variable and that the gene is subject to nucleotide insertions and deletions (LIMA et al 2002).…”

“…Several other authors have found the same genetic similarity between the Asian, American and Australian isolates (FERNÁNDEZ-RODRÍGUEZ et al 2008;LIMA et al 2002;LU et al 2008). These data confirm a possible Indian origin of PRSV, with a posterior spread to the Americas and Australia (OLARTE-CASTILLO et al 2011).…”

Development of virus resistant transgenic papayas expressing the coat protein gene from a Brazilian isolate of Papaya ringspot virus

“…Another R1 population, from a self-cross of the TS1j R0 plant (TS stands for translatable short), and a R2 population, from a selfed R1 PRSV resistant plant, which had been obtained from the cross between UM7c e UM1g R0 plants, were also screened for the presence of the cp gene by PCR and for resistance to other PRSV isolates from Brazil (PRSV BA-CA from Cruz das Almas, Bahia, and PRSV DF from Brasília, Distrito Federal) (Lima et al, 2002). TS1j and UM1g R0 plants have not been challenged by PRSV, and UM7c R0 plant were resistant to PRSV BR.…”

“…None of the R0 line was resistant to PRSV HA and PRSV TH, and susceptible to PRSV BR. When R1 and R2 populations were challenged with different Brazilian isolates, such as PRSV BA-CA and PRSV DF (Lima et al, 2002), resistant plants were seen in all of them, regardless of whether they descended from a single, double or even triple-resistant R0 plant. These results, together with the fact that the degree of similarity of the cp genes among the Brazilian isolates of PRSV is very high (Lima et al, 2002), strongly indicate that a variety with a broad spectrum of resistance to PRSV isolates from Brazil can be developed out of the 13 R1 and R2 populations selected.…”

Caracterização de novos isolados fracos do vírus do mosaico do mamoeiro ocorrendo naturalmente no estado do Espírito Santo; Avaliação da infecção natural de cucurbitáceas com esse vírus; Caracterização de um isolado do mosaico da alfafa infectando mamoeiro (Carica papaya) em campo

“…et al, 2007). O mosaico do mamoeiro é considerado um fator limitante para a produção em todos os países onde ocorre, além de provocar o aparecimento de manchas nos frutos que depreciam sua qualidade junto ao consumidor (JENSEN, 1949;TORRES;GIACOMETTI, 1966;HARKNESS, 1967;KAMADA, 1969;PURCIFUL et al, 1984;FANCELLI, 1997 (BATESON et al, 1994(BATESON et al, , 2002SILVA-ROSALES et al, 2000;LIMA et al, 2002;HEMA;PRASAD, 2004;JAIN et al, 2004;NOA-CARRAZANA;GONZALEZ-DE-LEÓN;INOUE-NAGATA et al, 2007;SILVA-ROSALES, 2007;WEI et al, 2007;FERNÁNDEZ-RODRÍGUEZ et al, LU et al, 2008;MANGRAUTHIA et al, 2008;TRIPATHI et al, 2008). Geralmente, os isolados do PRSV-P apresentam dois grupos de filogenia, um grupo de isolados do continente americano juntamente com isolados da Austrália e alguns isolados da Índia e outro grupo com isolados asiáticos.…”