scholarly journals Development of Mild Strains of Papaya Ringspot Virus-Papaya Strain

1970 ◽  
pp. 94-97
Author(s):  
S Mowlick ◽  
AM Akanda ◽  
AHMA Rahman
Keyword(s):  
Virus Infection ◽  
Key Words ◽  
Uv Radiation ◽  
Sodium Azide ◽  
Nitrous Acid ◽  
Cross Protection ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Inoculation Test ◽  
Challenge Inoculation

An attempt was made with BARI papaya-1 to develop the mild strains of Papaya ringspot virus-papaya strain (PRSV-P) to use in cross protection. Three mutagents (viz. nitrous acid, sodium azide and UV radiation) with different concentrations and exposure time were used in this experiment. Mutagenic treatments of extraction of PRSV-P infected sap with 0.075M nitrous acid, 2% sodium azide, and exposure to UV radiation for 1 and 2 minutes were observed to be the best in the production of effective mild strains of PRSV-P. The mild strains of PRSV-P containing papaya seedlings were faced to challenge inoculation test. It was observed that younger seedling condition delayed the virus infection as compared to older ones. Key words: PRSV-P, mutagenic treatments, cross protection. DOI = 10.3329/jard.v5i1.1464 J Agric Rural Dev 5(1&2), 94-97, June 2007

scholarly journals Effect of mild strain on severity of PRSV-W infection

1970 ◽  
Vol 35 (2) ◽  
pp. 279-285
Author(s):  
MF Rahman ◽  
MA Akanda ◽  
MZA Sarkar
Keyword(s):  
Uv Radiation ◽  
Sodium Azide ◽  
Nitrous Acid ◽  
Cross Protection ◽  
Avirulent Strain ◽  
Mild Strain ◽  
Chenopodium Amaranticolor ◽  
Challenge Inoculation ◽  
Severe Strain ◽  
Time Gap

Studies were conducted to develop mild/avirulent strain of PRSV-W using nitrous acid, sodium azide and UV-radiation for the mutagenic treatments. Among the three mutagens’ sodium azide at 3%, 4%, and 5%, and nitrous acid at 0.1M and 0.125M were proved to be effective in producing mild/avirulent strains of PRSV-W, while UV-radiation was proved to be ineffective. Evaluation on the effectivity of mild/avirulent strains in net house in protecting severe strain of PRSV-W proved that the efficiency of mild/avirulent strain to protect the severe strain of the virus was dependent upon the time gap between the mild strain inoculation and challenge inoculation. The challenge inoculation with the severe strain of PRSV-W after 12 days of mild strain inoculation could confer the cross-protection in about 64% pumpkin plants upto 40 days. The presence of mild/avirulent strains of PRSV-W in the asymptomatic plants challenged with severe strain of PRSV-W was tested by mechanical inoculation of Chenopodium amaranticolor to observe the development of characteristic local lesions of PRSV-W. Keywords: PRSV; cross protection. DOI: 10.3329/bjar.v35i2.5891Bangladesh J. Agril. Res. 35(2) : 279-285, June 2010

Generation of mild recombinants of papaya ringspot virus to minimize the problem of strain-specific cross protection

2021 ◽  
Author(s):  
Thi-Thu-Yen Tran ◽  
Tzu-Tung Lin ◽  
Chung-Ping Chang ◽  
Chun-Hung Chen ◽  
Van-Hoa Nguyen ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Carica Papaya ◽  
Genomic Sequence ◽  
Cross Protection ◽  
Ringspot Virus ◽  
Limiting Factor ◽  
Papaya Ringspot Virus ◽  
Severe Damage ◽  
Mild Strain ◽  
Geographic Regions

Papaya ringspot virus (PRSV) causes severe damage to papaya (Carica papaya L.) and is the primary limiting factor for papaya production worldwide. A nitrous acid-induced mild strain PRSV HA 5-1, derived from Hawaii strain HA, has been applied to control PRSV by cross protection for decades. However, the problem of strain-specific protection hampers its application in Taiwan and other geographic regions outside Hawaii. Here, sequence comparison of the genomic sequence of HA 5-1 with that of HA revealed 69 nucleotide changes, resulting in 31 aa changes in which 16 aa are structurally different. The multiple mutations of HA 5-1 are considered resulting from nitrous-acid induction since 86% of nucleotide changes are transition mutations. The stable HA 5-1 was used as a backbone to generate recombinants carrying individual 3’ fragments of Vietnam severe strain TG5, including NIa, NIb, and CP3’ regions, individually or in combination. Our results indicated that the best heterologous fragment for the recombinant is the region of CP3’, with which symptom attenuation of the recombinant is like that of HA 5-1. This mild recombinant HA51/TG5-CP3’ retained high levels of protection against the homologous HA in papaya plants and significantly increased the protection against the heterologous TG-5. Similarly, HA 5-1 recombinants carrying individual CP3’ fragments from Thailand SMK, Taiwan YK, and Vietnam ST2 severe strains also significantly increase the protection against the corresponding heterologous strains in papaya plants. Thus, our recombinant approach for mild strain generation is a fast and effective way to minimize the problem of strain-specific protection.

Genetic analysis of an attenuated Papaya ringspot virus strain applied for cross-protection

2007 ◽  
Vol 118 (4) ◽  
pp. 333-348 ◽  
Author(s):  
Chu-Hui Chiang ◽  
Chun-Yee Lee ◽  
Ching-Hsien Wang ◽  
Fuh-Jyh Jan ◽  
Shih-Shun Lin ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Virus Strain ◽  
Cross Protection ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus

scholarly journals Control of Papaya Ringspot Virus-Type W in Zucchini Squash by Cross-Protection in Brazil

Plant Disease ◽  
1998 ◽  
Vol 82 (2) ◽  
pp. 171-175 ◽  
Author(s):  
J. A. M. Rezende ◽  
D. A. Pacheco
Keyword(s):  
Virus Type ◽  
Large Scale ◽  
Field Tests ◽  
Mosaic Disease ◽  
Cross Protection ◽  
Ringspot Virus ◽  
Papaya Ringspot Virus ◽  
Effective Protection ◽  
Negative Effect ◽  
Protected Plants

Two mild strains of papaya ringspot virus-type W (PRSV-W) were tested under greenhouse and field conditions to study the potential of cross-protection for control of zucchini squash mosaic. Protected plants of zucchini squash cultivars Caserta and Clarinda were challenged with three severe strains from different geographic regions of the country in tests carried out in the greenhouse. Challenge inoculations were done mechanically 10 and 20 days after the protective inoculation. The mild strains did not have a visible negative effect on the development of the plants and offered effective protection against the severe strains. Field tests of protected Caserta plants were carried out in Piracicaba County, São Paulo. Comparative evaluation based on the symptoms and development of protected and unprotected plants of zucchini squash showed that both mild strains effectively protected the plants against the effects of the severe strain present in the field. Yield of marketable fruits harvested from protected plants was only 10% less than that of the healthy plants in one field trial. Compared with the yield from plants infected with the severe strains, protected plants showed an increase of 511 and 633% in the number and weight of marketable fruits, respectively, in a test in 1994. In a second experiment in 1995, an increase of 327% in the number and 344% in the weight of marketable fruits was recorded. These studies demonstrate the effectiveness of cross-protection for the control of the mosaic disease caused by PRSV-W in zucchini squash and offer growers a method for large-scale application of this technology.

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