scholarly journals Field Evaluation of Transgenic Papaya Lines Carrying the Coat Protein Gene of Papaya ringspot virus in Taiwan

Plant Disease ◽  
2004 ◽  
Vol 88 (6) ◽  
pp. 594-599 ◽  
Author(s):  
Huey-Jiunn Bau ◽  
Ying-Huey Cheng ◽  
Tsong-Ann Yu ◽  
Jiu-Sherng Yang ◽  
Pan-Chi Liou ◽  
...  
Keyword(s):  
Coat Protein ◽  
Transgenic Plants ◽  
Rainy Season ◽  
Field Evaluation ◽  
Weather Conditions ◽  
Fruit Production ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Transgenic Papaya ◽  
Transgenic Lines

Four transgenic papaya lines expressing the coat protein (CP) gene of Papaya ringspot virus (PRSV) were evaluated under field conditions for their reaction to PRSV infection and fruit production in 1996 to 1999. Plants were exposed to natural virus inoculation by aphids in two adjacent fields in four different plantings at the same sites. None of the transgenic lines showed severe symptoms of PRSV whereas control nontransgenic plants were 100% severely infected 3 to 5 months after planting. In the first and second trials, 20 to 30% of the transgenic plants showed mild symptoms consisting of confined mottling or chlorotic spots on leaves. The number of transgenic plants with mild symptoms fluctuated according to the season and weather conditions, with a tendency to increase in the winter or rainy season and decrease in the summer. Also, the incidence of the mild symptoms in the third trial increased significantly due to infection by root rot fungi during the rainy season. Interestingly, there was no apparent adverse effect on fruit yield and quality in transgenic plants with mild symptoms. In the first and second experiments, transgenic lines yielded 10.8 to 11.6 and 54.3 to 56.7 times more marketable fruit, respectively, than controls. All transgenic plants produced fruit of marketable quality with no ringspots or distortion.

scholarly journals Generation of Transgenic Papaya with Double Resistance to Papaya ringspot virus and Papaya leaf-distortion mosaic virus

2009 ◽  
Vol 99 (11) ◽  
pp. 1312-1320 ◽  
Author(s):  
Yi-Jung Kung ◽  
Huey-Jiunn Bau ◽  
Yi-Ling Wu ◽  
Chiung-Huei Huang ◽  
Tsui-Miao Chen ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Field Tests ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Coding Region ◽  
Transgenic Papaya ◽  
Resistant Lines ◽  
Transgenic Lines ◽  
Chimeric Construct ◽  
Leaf Distortion

During the field tests of coat protein (CP)-transgenic papaya lines resistant to Papaya ringspot virus (PRSV), another Potyvirus sp., Papaya leaf-distortion mosaic virus (PLDMV), appeared as an emerging threat to the transgenic papaya. In this investigation, an untranslatable chimeric construct containing the truncated CP coding region of the PLDMV P-TW-WF isolate and the truncated CP coding region with the complete 3′ untranslated region of PRSV YK isolate was transferred into papaya (Carica papaya cv. Thailand) via Agrobacterium-mediated transformation to generate transgenic plants with resistance to PLDMV and PRSV. Seventy-five transgenic lines were obtained and challenged with PRSV YK or PLDMV P-TW-WF by mechanical inoculation under greenhouse conditions. Thirty-eight transgenic lines showing no symptoms 1 month after inoculation were regarded as highly resistant lines. Southern and Northern analyses revealed that four weakly resistant lines have one or two inserts of the construct and accumulate detectable amounts of transgene transcript, whereas nine resistant lines contain two or three inserts without significant accumulation of transgene transcript. The results indicated that double virus resistance in transgenic lines resulted from double or more copies of the insert through the mechanism of RNA-mediated posttranscriptional gene silencing. Furthermore, three of nine resistant lines showed high levels of resistance to heterologous PRSV strains originating from Hawaii, Thailand, and Mexico. Our transgenic lines have great potential for controlling a number of PRSV strains and PLDMV in Taiwan and elsewhere.

scholarly journals Virus Coat Protein Transgenic Papaya Provides Practical Control of Papaya ringspot virus in Hawaii

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 101-105 ◽  
Author(s):  
S. A. Ferreira ◽  
K. Y. Pitz ◽  
R. Manshardt ◽  
F. Zee ◽  
M. Fitch ◽  
...  
Keyword(s):  
Coat Protein ◽  
Transgenic Line ◽  
Field Trials ◽  
Fruit Production ◽  
Ringspot Virus ◽  
Soluble Solids ◽  
Production Data ◽  
Papaya Ringspot Virus ◽  
The Matrix ◽  
Virus Coat

Since 1992, Papaya ringspot virus (PRSV) destroyed nearly all of the papaya hectarage in the Puna district of Hawaii, where 95% of Hawaii's papayas are grown. Two field trials to evaluate transgenic resistance (TR) were established in Puna in October 1995. One trial included the following: SunUp, a newly named homozygous transformant of Sunset; Rainbow, a hybrid of SunUp, the nontransgenic Kapoho cultivar widely grown in Puna, and 63-1, another segregating transgenic line of Sunset. The second trial was a 0.4-ha block of Rainbow, simulating a near-commercial planting. Both trials were installed within a matrix of Sunrise, a PRSV-susceptible sibling line of Sunset. The matrix served to contain and trace pollen flow from TR plants, and as a secondary inoculum source. Virus infection was first observed 3.5 months after planting. At a year, 100% of the non-TR control and 91% of the matrix plants were infected, while PRSV infection was not observed on any of the TR plants. Fruit production data of SunUp and Rainbow show that yields were at least three times higher than the industry average, while maintaining percent soluble solids above the minimum of 11% required for commercial fruit. These data suggest that transgenic SunUp and Rainbow, homozygous and hemizygous for the coat protein transgene, respectively, offer a good solution to the PRSV problem in Hawaii.

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

2002 ◽  
Vol 27 (2) ◽  
pp. 174-180 ◽  
Author(s):  
ROBERTO C. A. LIMA ◽  
MANOEL T. SOUZA JR. ◽  
GILVAN PIO-RIBEIRO ◽  
J. ALBERSIO A. LIMA
Keyword(s):  
Coat Protein ◽  
Carica Papaya ◽  
Protein Gene ◽  
Average Degree ◽  
Ringspot Virus ◽  
Plant Genome ◽  
Papaya Ringspot Virus ◽  
Transgenic Papaya ◽  
Cp Gene ◽  
Worldwide Production

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.

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

2005 ◽  
Vol 30 (4) ◽  
pp. 357-365 ◽  
Author(s):  
Manoel T. Souza Júnior ◽  
Osmar Nickel ◽  
Dennis Gonsalves
Keyword(s):  
Coat Protein ◽  
Carica Papaya ◽  
Protein Gene ◽  
Transformation Efficiency ◽  
Ringspot Virus ◽  
Zygotic Embryos ◽  
Papaya Ringspot Virus ◽  
Secondary Somatic Embryo ◽  
Embryo Cultures ◽  
Transgenic Lines

Translatable and nontranslatable versions of the coat protein (cp) gene of a Papaya ringspot virus (PRSV) isolate collected in the state of Bahia, Brazil, were engineered for expression in Sunrise and Sunset Solo varieties of papaya (Carica papaya). The biolistic system was used to transform secondary somatic embryo cultures derived from immature zygotic embryos. Fifty-four transgenic lines, 26 translatable and 28 nontranslatable gene versions, were regenerated, with a transformation efficiency of 2.7%. Inoculation of cloned R0 plants with PRSV BR, PRSV HA or PRSV TH, Brazilian, Hawaiian and Thai isolates, respectively, revealed lines with mono-, double-, and triple-resistance. After molecular analysis and a preliminary agronomic evaluation, 13 R1 and R2 populations were incorporated into the papaya-breeding program at Embrapa Cassava and Tropical Fruits, in Cruz das Almas, Bahia, Brazil.

scholarly journals Field Resistance of Coat Protein Transgenic Papaya to Papaya ringspot virus in Jamaica

Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 841-847 ◽  
Author(s):  
Paula Tennant ◽  
M. H. Ahmad ◽  
D. Gonsalves
Keyword(s):  
Disease Resistance ◽  
Coat Protein ◽  
Carica Papaya ◽  
Virus Disease ◽  
Field Resistance ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Two Generations ◽  
Transgenic Lines ◽  
Severe Leaf

Transgenic papayas (Carica papaya) containing translatable coat protein (CPT) or nontranslatable coat protein (CPNT) gene constructs were evaluated over two generations for field resistance to Papaya ringspot virus in a commercial papaya growing area in Jamaica. Reactions of R0 CPT transgenic lines included no symptoms and mild or severe leaf and fruit symptoms. All three reactions were observed in one line and among different lines. Trees of most CPNT lines exhibited severe symptoms of infection, and some also showed mild symptoms. R1 offspring showed reactions previously observed with parental R0 trees; however, reactions not previously observed or a lower incidence of the reaction were also obtained. The transgenic lines appear to possess virus disease resistance that can be manipulated in subsequent generations for the development of a product with acceptable commercial performance.

scholarly journals Sequence similarity between the viral cp gene and the transgene in transgenic papayas

2005 ◽  
Vol 40 (5) ◽  
pp. 479-486 ◽  
Author(s):  
Manoel Teixeira Souza Júnior ◽  
Dennis Gonsalves
Keyword(s):  
Comparative Analysis ◽  
Coat Protein ◽  
Transgenic Plants ◽  
Sequence Similarity ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
High Sequence Similarity ◽  
Mechanism Of Resistance ◽  
Cp Gene ◽  
Do So

The Papaya ringspot virus (PRSV) coat protein transgene present in 'Rainbow' and 'SunUp' papayas disclose high sequence similarity (>89%) to the cp gene from PRSV BR and TH. Despite this, both isolates are able to break down the resistance in 'Rainbow', while only the latter is able to do so in 'SunUp'. The objective of this work was to evaluate the degree of sequence similarity between the cp gene in the challenge isolate and the cp transgene in transgenic papayas resistant to PRSV. The production of a hybrid virus containing the genome backbone of PRSV HA up to the Apa I site in the NIb gene, and downstream from there, the sequence of PRSV TH was undertaken. This hybrid virus, PRSV HA/TH, was obtained and used to challenge 'Rainbow', 'SunUp', and an R2 population derived from line 63-1, all resistant to PRSV HA. PRSV HA/TH broke down the resistance in both papaya varieties and in the 63-1 population, demonstrating that sequence similarity is a major factor in the mechanism of resistance used by transgenic papayas expressing the cp gene. A comparative analysis of the cp gene present in line 55-1 and 63-1-derived transgenic plants and in PRSV HA, BR, and TH was also performed.

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