Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Gene Technology for Papaya Ringspot Virus Disease Management

Md. Abul Kalam Azad
Department of Agricultural Extension, Khamarbari, Farmgate, Dhaka 1215, Bangladesh

Latifah Amin
Centre for General Studies, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor, Malaysia

Nik Marzuki Sidik
Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor, Malaysia

Abstract/ Executive Summary:

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.

Keywords: Gene Technology, Papaya, Ringspot Virus, Disease Management

Location:

Start Date:

End Date:

Program Area: Pest Management

Commodity: Papaya, Virus

Objectives:

This review paper aims to review recent development of PRSV, genomic, diversity of PRSV, molecular identification, hostrange determinants and vector transmission, biosafety, major challenges, and future research directions.

Methodology:

2. The Genome of the Papaya Ringspot Virus (PRSV) PRSV is of the genus Potyvirus and of the family Potyviridae. The genome of PRSV consists of 800–900 nm long nonenveloped flexuous filamentous particles with an ssRNA genome of about 10,324 nucleotides. The virion contains 94.5% protein and 5.5% nucleic acid by weight. The PRSV genome encodes a single large protein (3,344 amino acids) which is subsequently cleaved into smaller proteins with various functions. The proposed locations of the cleavage sites predict eight to nine proteins consisting of P1 (63K), helper component (HC-Pro, 52K), P3 (46K), cylindrical inclusion protein (C1, 72K), nuclear inclusion protein a (NIa, 48K), nuclear inclusion protein b (NIb, 59K), and coat protein (CP, 35K). The P1 protein is encoded by the Potyvirus genome and autocatalytically cleaves. The P1 protein is the least conserved protein and can move systemically in infected plants. The helper component (HC-Pro) is a multifunctional protein which mediates aphid transmission, symptom expression, long distance movement, genome amplification, and suppression of posttranscriptional gene silencing (PTGS). HCPro is a highly effective suppressor of RNA silencing. It can affect the microRNA-mediated development pathway in plants and help in the establishment of the heterologous virus. The long distance movement and genome replication of HC-Pro depends on PTGS suppression. HC-Pro is responsible for synergism between polyviruses and unrelated viruses that can cause severe symptoms and an accumulation of virus in infected leaves. The C1 protein of PRSV has NTP binding, NTPase, RNA binding, and RNA helicase activity. The NIa has two domains defined as the N-terminal genome-linked protein (VPg) and C-terminal domain. The VPg is required for priming RNA synthesis. Nib is a codependent RNA polymerase that has been shown to have replicase activity. CP is involved in aphid transmission systemic movement and the encapsidation of the viral RNA [28]. The PRSV is divided into two major biotypes or strains based on their host range. The PRSV-W type affects cucurbits but not papaya while the PRSV-P type affects papaya and cucurbits. 3. The Genetic Diversity of PRSV Knowledge of the genetic diversity of PRSV is important for effective evidence-based disease management. The genetic diversity of PRSV was observed in different regions of the world. Sequence diversity among isolates of the virus and their distribution are important for establishing virus origin, development, dispersion, and disease etiology, in the pursuit of effective virus disease management. There is little sequence variation among the CP genes of PRSV isolates from the USA and Australia. On the other hand, there is greater sequence variation amongst the CP genes of PRSV isolates from India and Mexico. The diversity at amino acid and nucleic acid levels was highest among the Asian population of PRSV isolates. The PRSV isolates from India differed from the PRSV isolates from other countries. Bateson et al. reported that the origin of PRSV was South Asia and found a greater diversity in PRSV isolates from India. The differences in PRSV were observed due to differences in the CP gene length.The highest diversity of PRSV nucleotide sequences was found in the CP and HC-Pro genes collected from India [40]. PRSV might have been transported from India to America in the early 18th century and spread in 19th and 20th centuries. Variation in the CP gene sequences of PRSV was observed in different parts of the world.The genetic diversity of PRSV depends on geographical location. For example, the transgenic papaya incorporating CP gene (HA 5-1) isolated from USA showed resistance to PRSV infection by the severe USA isolate (HA) but did not show resistance against infection by the Australian andThai isolates of PRSV.

Source of Information: The Scientific World Journal Volume 2014, Article ID 768038, 11 pages

Article Link (Online Journal): http://dx.doi.org/10.1155/2014/768038

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

PRSV is the major threat for papaya production. Transgenic papaya via gene technology has been used for PRSV disease management. In this review, we find that PRSV-resistant papaya varieties have been developed using CP genes or RNA interference. The genetic diversity of PRSV has been identified throughout the world. The breakdown of PRSV resistance is the major challenge facing transgenic papaya cultivation. Although, the gene flow of PRSV-transgenic papaya is low, research towards minimizing this problem should be conducted. The adoption of PRSV-resistant transgenic papaya is still slow and it depends upon the demand for papaya, biosafety regulations, and social acceptance of the technology. Recent studies indicate that PRSV-resistant transgenic papaya is environmentally safe and has no adverse effects on human health. Posttranscriptional gene silencing (PTGS) technology may be suitable for the development of PRSV-resistant transgenic papaya in future. This review suggests that papaya producing countries should develop PRSVresistant transgenic papaya using their own PRSV isolates through posttranscriptional gene silencing technology.

Knowledge Management: Journal