Comparison of Infection Caused by Pythium Debaryanum, Phytophthora Palmivora and Erwinia Caricae on Transgenic and Non-Transgenic Papaya Ringspot Virus Resistant Plants

A virus identified as a new pathotype of Papaya leaf distortion mosaic virus (PLDMV, P-TW-WF) was isolated from diseased papaya in an isolated test-field in central Taiwan, where transgenic papaya lines resistant to Papaya ringspot virus (PRSV) were evaluated. The infected plants displayed severe mosaic, distortion and shoe-stringing on leaves; stunting in apex; and water-soaking on petioles and stems. This virus, which did not react in enzyme-linked immunosorbent assay with the antiserum to the PRSV coat protein, infected only papaya, but not the other 18 plant species tested. Virions studied under electron microscope exhibited morphology and dimensions of potyvirus particles. Reverse transcription-polymerase chain reaction conducted using potyvirus-specific primers generated a 1,927-nucleotide product corresponding to the 3′ region of a potyvirus, showing high sequence identity to the CP gene and 3′ noncoding region of PLDMV. Search for similar isolates with the antiserum against CP of P-TW-WF revealed scattered occurrence of PLDMV in Taiwan. Phylogenetic analysis of PLDMV isolates of Taiwan and Japan indicated that the Taiwan isolates belong to a separate genetic cluster. Since all the Taiwan isolates infected only papaya, unlike the cucurbit-infecting Japanese P type isolates, the Taiwan isolates are considered a new pathotype of PLDMV. Susceptibility of all our PRSV-resistant transgenic papaya lines to PLDMV indicates that the virus is an emerging threat for the application of PRSV-resistant transgenic papaya in Taiwan and elsewhere.

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Gene Technology for Papaya Ringspot Virus Disease Management

The Scientific World JOURNAL ◽

10.1155/2014/768038 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 14

Author(s):

Md. Abul Kalam Azad ◽

Latifah Amin ◽

Nik Marzuki Sidik

Keyword(s):

Genetic Diversity ◽

Disease Management ◽

Virus Disease ◽

Management Strategies ◽

Ringspot Virus ◽

Transcriptional Gene Silencing ◽

Replicase Gene ◽

Gene Technology ◽

Papaya Ringspot Virus ◽

Transgenic Papaya

Papaya (Carica papaya) is severely damaged by the papaya ringspot virus (PRSV). This review focuses on the development of PRSV resistant transgenic papaya through gene technology. The genetic diversity of PRSV depends upon geographical distribution and the influence of PRSV disease management on a sequence of PRSV isolates. The concept of pathogen-derived resistance has been employed for the development of transgenic papaya, using a coat protein-mediated, RNA-silencing mechanism and replicase gene-mediated transformation for effective PRSV disease management. The development of PRSV-resistant papaya via post-transcriptional gene silencing is a promising technology for PRSV disease management. PRSV-resistant transgenic papaya is environmentally safe and has no harmful effects on human health. Recent studies have revealed that the success of adoption of transgenic papaya depends upon the application, it being a commercially viable product, bio-safety regulatory issues, trade regulations, and the wider social acceptance of the technology. This review discusses the genome and the genetic diversity of PRSV, host range determinants, molecular diagnosis, disease management strategies, the development of transgenic papaya, environmental issues, issues in the adoption of transgenic papaya, and future directions for research.

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The Use of Transgenic Papaya to Control Papaya Ringspot Virus in Hawaii, and the Transfer of this Technology to Other Countries

Handbook of Plant Biotechnology ◽

10.1002/0470869143.kc061 ◽

2004 ◽

Cited By ~ 1

Author(s):

Dennis Gonsalves ◽

Gustavo Fermin

Keyword(s):

Ringspot Virus ◽

Papaya Ringspot Virus ◽

Transgenic Papaya

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

Phytopathology ◽

10.1094/phyto-99-11-1312 ◽

2009 ◽

Vol 99 (11) ◽

pp. 1312-1320 ◽

Cited By ~ 38

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.

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Transgenic Papaya: A Case for Managing Risks of Papaya ringspot virus in Hawaii

Plant Health Progress ◽

10.1094/php-2003-1113-03-rv ◽

2003 ◽

Vol 4 (1) ◽

pp. 17 ◽

Cited By ~ 15

Author(s):

Dennis Gonsalves ◽

Steve Ferreira

Keyword(s):

The State ◽

Ringspot Virus ◽

Papaya Ringspot Virus ◽

Resistant Line ◽

F1 Hybrid ◽

Japanese Market ◽

Transgenic Papaya ◽

Hawaii Island ◽

Growing Region

In May 1992, Papaya ringspot virus (PRSV) was detected in the Puna district of Hawaii Island, the main papaya growing region of the state of Hawaii. By 1994 Hawaii's papaya industry was facing devastating damage from PRSV. Efforts to develop resistant transgenic papaya were started in the mid 1980s and a resistant line was identified in 1991. Two cultivars were developed from this line and were commercialized in 1998. Rainbow, an F1 hybrid from a cross of the transgenic SunUp, and nontransgenic Kapoho are now widely planted and have helped save the papaya industry. In addition, PRSV inocula in Puna were greatly reduced as abandoned infected fields were replanted with transgenic papaya. These conditions have allowed growers to continue the production of nontransgenic Kapoho in Puna to keep the Japanese market supplied, since transgenic papaya is not yet deregulated in that country. Accepted for publication 5 November 2003. Published 13 November 2003.

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

Plant Disease ◽

10.1094/pdis.2004.88.6.594 ◽

2004 ◽

Vol 88 (6) ◽

pp. 594-599 ◽

Cited By ~ 27

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.

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