Potato Virus Y (potato + virus_y)

Distribution by Scientific Domains

Selected Abstracts

Production of monoclonal antibodies against synthetic peptides of the N-terminal region of Potato virus Y coat protein and their use in PVY strain differentiation

H. Ounouna
Antibodies were prepared against two synthetic peptides, P19 and P11, derived from the coat protein N-terminal region of two pepper isolates of Potato virus Y from Tunisia (PVY-P21 and PVY-P2, respectively). The peptides were selected by comparing the predicted amino acid sequences of three pepper and four potato PVY isolates on the basis of their polymorphism and hydrophilicity. Sera with high titres were only obtained against P19. Three MAbs, raised in response to P19, reacted with the homologous virus (PVY-P21) in TAS-ELISA. When tested against a broad range of PVY isolates and related viruses, MAb 3C5 proved to be PVY species specific, whereas MAbs 8A4 and 1D6 reacted specifically with standard isolates of PVYO, PVYC and PVYN -W strains, but not with other PVY isolates. Consequently, epitope(s) recognized by 8A4 and 1D6 MAbs may be specific to a PVY group comprising all serologically PVYnon,N isolates. Surprisingly, and unlike isolate PVY-P21, many Tunisian field pepper isolates did not carry this epitope(s), thus revealing serological heterogeneity within the PVY pepper group. As PVY is one of the most economically important plant pathogens in a range of crops, including pepper, these MAbs will provide a useful tool for practical diagnosis and strain identification of PVY. [source]

Biological and sequence comparisons of Potato virus Y isolates associated with potato tuber necrotic ringspot disease

N. Boonham
The biological and molecular relationships between a large number of Potato virus Y (PVY) isolates were examined, concentrating mainly on isolates associated with potato tuber necrotic ringspot disease (PTNRD). Following detailed analysis of the coat-protein gene, four main groups were identified which broadly corresponded to the phenotype of the different isolates. The groups comprised the ordinary strain (PVYO), the necrotic strain (PVYN), the C strain (PVYC) and a group of recombinant (between ordinary and necrotic) isolates. In the latter group, all members were associated with PTNRD. However, four nonrecombinant isolates were also identified which were associated with PTNRD or tuber necrosis. Three were from tubers showing PTNRD symptoms in the field, while the fourth originated from symptomless tubers, but could cause necrotic rings on tubers under glasshouse conditions. The results show that although coat-protein recombination is always found associated with the PTNRD phenotype, some nonrecombinant isolates have very similar biological properties. [source]

Determination of aphid transmission efficiencies for N, NTN and Wilga strains of Potato virus Y

M. Verbeek
Potato virus Y (PVY, genus Potyvirus, family Potyviridae) causes high economic losses worldwide, especially in the production of seed potatoes (Solanum tuberosum). PVY control systems rely on measuring virus pressure and vector pressure in the field. Calculation of the vector pressure is based on the relative efficiency factors (REFs) of aphid species. These REFs express the transmission efficiency of aphid species in relation to the transmission efficiency of Myzus persicae, the most efficient vector of PVY. In this paper, we report on the determination of aphids' relative transmission efficiency factors (REFs) for isolates of the PVY strains PVYN, PVYNTN and PVYN-Wi. Biotype Mp2 of M. persicae was tested for its transmission efficiency for six PVY isolates (one PVYN, three PVYNTN and two PVYN-Wi isolates) and showed comparable average transmission efficiencies for all isolates. The transmission rate of this biotype for the six PVY isolates was set to 1 and Mp2 was used as an internal control in transmission experiments to determine the REFs of three other biotypes of M. persicae and 16 other aphid species (three biotypes per species when available) for the six PVY isolates. Comparing the calculated REFs for PVYN with the REFs reported in the previous century for PVYN, we observe overall comparable REFs, except for Aphis fabae, Aphis spp., Hyperomyzus lactucae, Macrosiphum euphorbiae and Rhopalosiphum padi, which have a lower REF in our experiments, and Aphis frangulae and Phorodon humuli, which have now a higher REF. Comparing the new REFs found for the PVYNTN strains with the new REFs for PVYN, we observe that they are overall comparable, except for A. frangulae (0.17 compared with 0.53) and Schizaphis graminum (0.05 compared with 0.00). Comparing the REFs calculated for PVYN-Wi with those calculated for PVYN, we can observe six aphid species with higher REFs (Acyrthosiphon pisum, A. fabae, Aphis nasturtii, Aphis spp., P. humuli and R. padi). Only the species A. frangulae shows a lower REF for PVYN-Wi compared with the transmission efficiency of PVYN. Three aphid species (Aulacorthum solani, Myzus ascalonicus and S. graminum) for which no REF was determined earlier were found to be capable to transmit PVY and their REFs were determined. [source]

Antiphytoviral activity of bruceine-D from Brucea javanica seeds

Jian-Guo Shen
Abstract BACKGROUND:Brucea javanica (L.) Merr. is widely distributed throughout the southern parts of China and has been used in traditional medicine to treat a variety of diseases. The objective of the present study was to identify the active antiphytoviral compound in the seeds of B. javanica and evaluate the inhibitory activity of the compound against plant virus. RESULTS: Bioassay-guided fractionation of the most active extract from the seeds led to the isolation of an antiphytoviral compound which was identified as bruceine-D by conventional spectroscopy methods. The compound exhibited significant inhibitory activity against the infection and replication of tobacco mosaic virus (TMV), with IC50 values of 13.98 and 7.13 mg L,1 respectively. The compound also showed a strong inhibitory effect on the infectivity of potato virus Y (PVY) and cucumber mosaic virus (CMV). Furthermore, the compound could effectively inhibit systemic TMV infection in the host tobacco plant under glasshouse conditions. CONCLUSION: The results suggested that bruceine-D from Brucea javanica may have the potential to be used as a natural viricide, or a lead compound for new viricides. Copyright 2007 Society of Chemical Industry [source]

Hydroxyproline-rich glycoprotein accumulation in tobacco leaves protected against Erysiphe cichoracearum by potato virus Y infection

V. Raggi
Tobacco cv. Havana 425 acquired resistance to a compatible isolate of Erysiphe cichoracearum after infection by a strain of potato virus Y (PVYN) that causes veinal necrosis; another common strain (PVYO) that does not cause necrosis gave less protection. Hydroxyproline-rich glycoproteins (HRGPs), believed to be involved in resistance, were determined by analysing hydroxyproline (Hyp) in purified cell walls. Hyp content increased significantly in PVYN -protected leaves, compared with untreated controls, 2,4 days after necrotic lesion symptoms developed. No further increase in Hyp was noted in PVYN -protected leaves after E. cichoracearum challenge. Hyp increases were significantly higher in protected leaves of plants showing symptoms on day 7 than on day 10. Infection with the PVYO strain caused significant decrease in Hyp content, compared with uninoculated controls. Inoculation of virus-free plants with E. cichoracearum induced moderate and transitory Hyp increases on day 2 or 3, followed by a quick decrease associated with a weak response by the compatible host. It is suggested that HRGP accumulation induced by PVYN (but not by PVYO) causes changes in the host cell wall that result in resistance to E. cichoracearum. [source]

Cryotherapy of shoot tips: a technique for pathogen eradication to produce healthy planting materials and prepare healthy plant genetic resources for cryopreservation

Q.C. Wang
Abstract Cryotherapy of shoot tips is a new method for pathogen eradication based on cryopreservation techniques. Cryopreservation refers to the storage of biological samples at ultra-low temperature, usually that of liquid nitrogen (,196C), and is considered as an ideal means for long-term storage of plant germplasm. In cryotherapy, plant pathogens such as viruses, phytoplasmas and bacteria are eradicated from shoot tips by exposing them briefly to liquid nitrogen. Uneven distribution of viruses and obligate vasculature-limited microbes in shoot tips allows elimination of the infected cells by injuring them with the cryo-treatment and regeneration of healthy shoots from the surviving pathogen-free meristematic cells. Thermotherapy followed by cryotherapy of shoot tips can be used to enhance virus eradication. Cryotherapy of shoot tips is easy to implement. It allows treatment of large numbers of samples and results in a high frequency of pathogen-free regenerants. Difficulties related to excision and regeneration of small meristems are largely circumvented. To date, severe pathogens in banana (Musa spp.), Citrus spp., grapevine (Vitis vinifera), Prunus spp., raspberry (Rubus idaeus), potato (Solanum tuberosum) and sweet potato (Ipomoea batatas) have been eradicated using cryotherapy. These pathogens include nine viruses (banana streak virus, cucumber mosaic virus, grapevine virus A, plum pox virus, potato leaf roll virus, potato virus Y, raspberry bushy dwarf virus, sweet potato feathery mottle virus and sweet potato chlorotic stunt virus), sweet potato little leaf phytoplasma and Huanglongbing bacterium causing ,citrus greening'. Cryopreservation protocols have been developed for a wide variety of plant species, including agricultural and horticultural crops and ornamental plants, and can be used as such or adjusted for the purpose of cryotherapy. [source]