Passion Fruit Woodiness Virus Research Articles

Sri Lankan passion fruit mottle virus, a potyvirus infecting golden passion fruit in Sri Lanka

SummaryA sap‐transmissible virus, provisionally named Sri Lankan passion fruit mottle virus (SLPFMV), was isolated from Passiflora edulis f. flavicarpa and shown to induce leaf mottling and distortion in that host. The virus infected 23 species in five plant families with systemic infection being common in the Passifloraceae. Chenopodium amaranticolor was a good local lesion host and Passiflora foetida was a useful systemic host for purification. In P. foetida extracts, SLPFMV lost infectivity after 10 min between 70–75°C, 6–7 days at 20–23°C and at dilutions of 10‐‐5 ‐W‐6. The virus had flexuous, filamentous particles with a normal length of c. 841 nm. Two polypeptides of mol. wt c. 33 200 and 28 700 were detected in purified virus preparations, and a major species of double‐stranded RNA (mol. wt 7.0 × 106), was detected in infected plants. Pinwheels, tubular and laminated inclusions were found in ultrathin sections of infected P. edulis f. plavicurpa and cylindrical inclusions were observed in epidermal strips.SLPFMV was transmitted by the aphids Myzus persicae, Aphis spiraecola, A. gossypü and A. cruccivora after brief acquisition feeds. SLPFMV reacted with antisera to several potyviruses including passion fruit woodiness virus, passion fruit ringspot virus, potato virus Y and watermelon mosaic virus 2 and thus, apparently, is a member of the potyvirus group.

Characterization and Comparison of Passionfruit Mottle Virus, a Newly Recognized Potyvirus, with Passionfruit Woodiness Virus

A virus, designated passionfruit mottle virus (PaMV), was isolated from plants of passionfruit cultivar Taunung No. 1, which showed mild mottling. Unlike the previously described passionfruit woodiness virus (PWV), PaMV does not induce severe foliage mosaic and woody, misshapen fruits. It was identified as a potyvirus on the basis of particle morphology, aphid transmissibility, and the ability to induce cytoplasmic cylindrical inclusions (CI) in infected cells. Of 25 plant species inoculated, 11 (Nicotiana benthamiana, four passiflora species, and six leguminous species) developed differential reactions (...)

Nomenclature and relationships of some Brazilian leguminous potyviruses related to bean common mosaic and/or passionfruit woodiness viruses.

The main Brazilian literature of the last 10 years on potyviruses of leguminous plants related to bean common mosaic virus (BCMV) and/or to passionfruit woodiness virus (PWV) is discussed and summarized. The viruses dealt with are canavalia acronecrosis, mosaico de canavalia, cassia yellow spot, cowpea green vein-banding, cowpea rugose mosaic and cowpea severe mottle. The viruses have similar biological properties, such as a host range restricted mainly to the Leguminosae, aphid transmission, seed transmission in leguminous plants, and various degrees of serological relationships with BCMV and PWV.

Coat protein of potyviruses 7. Amino acid sequence of peanut stripe virus

The amino acid sequence of the 287-residue coat protein of peanut stripe virus (PStV) was determined from the sequences of overlapping peptide fragments. Results indicated that the amino terminus was blocked by an acetyl group, as has previously been found for the coat protein of Johnsongrass mosaic potyvirus. Comparison of the PStV sequence with coat proteins of 20 distinct potyviruses gave sequence identities of 47-57%, except for zucchini yellow mosaic virus (ZYMV), passionfruit woodiness virus (PWV), and the related strains watermelon mosaic virus 2 (WMV 2) and soybean mosaic virus-N, which showed sequence identities of 70-76%. Several amino acid residues which were common to the core sequences of these coat proteins were at positions previously found to be invariant among potyvirus coat proteins. The degree of these similarities suggests that although PStV, WMV 2, ZYMV, and PWV are distinct potyviruses, they share a common ancestor in their evolutionary development.

Sequential appearance of capsid protein and cylindrical inclusion protein in root-tip cells following infection with passion fruit woodiness virus

Early events in passion fruit woodiness virus (PWV) infection of root-tip cells of tobacco ( Nicotiana benthamiana) were examined by immunoelectron microscopy with antisera prepared specifically against the capsid protein (CP) and cylindrical inclusion protein (CIP) of the virus. Capsid protein was first detected on the cytoplasmic virus-specific vesicles coincident with first appearance of virions, but virions were not visible at every location that was stained. Early configurations of cylindrical inclusions (CI) were first observed on the surface of endoplasmic reticulum. At a later stage when aggregates of PWV were present, PWV virions were intimately associated with CIs either within the cytoplasm or attached perpendicularly to the cell wall. Most PWV aggregates were bound to cytoplasmic membranous structures in cells at a late stage of infection. Antiserum against CP partially reacted with CIs at advanced stages of infection. On the other hand, antiserum against CIP reacted only with CIs, but not with PWV virions. Both CP and CIP could also be detected in the plasmodesmata of infected cells.

Coat protein of Potyviruses

Three strains of passionfruit woodiness virus, Tip Blight (PWV-TB), Severe (PWV-S) and Mild (PWV-M), were compared on the basis of their biological, serological and coat protein structural properties. Each of the strains could be distinguished on the basis of their reactions on selected test plant species but no differences were observed in the serological properties of the three PWV strains. Molecular weight estimates on SDS-PAGE suggest the PWV coat protein contains 275 amino acid residues and sequence data for 269 of these residues is presented. The amino terminal peptide is blocked and has not been sequenced. The coat proteins of PWV-TB and PWV-S, which cause severe symptoms in infected plants, showed only three sequence differences compared to the eleven or twelve sequence changes between their coat proteins and that of the mild strain. The high sequence homology (96-99%) between the three PWV strains is similar to that previously reported for two strains of tobacco etch virus and three strains of sugarcane mosaic virus. Sequence homology between the three strains of PWV and published sequences for the coat proteins of eight distinct potyviruses ranged from 43-71% (average 57%).

The N and C Termini of the Coat Proteins of Potyviruses Are Surface-located and the N Terminus Contains the Major Virus-specific Epitopes

Summary Mild proteolysis by trypsin of particles of six potyviruses (bean yellow mosaic virus, clover yellow vein virus, Johnson grass mosaic virus, passion-fruit woodiness virus, potato virus Y and watermelon mosaic virus II) revealed that the N- and C-terminal regions of their coat protein are exposed on the particles’ surfaces. The enzyme treatment removed the N-terminal region (30 to 67 amino acids long, depending on the virus) and 18 to 20 amino acids from the C terminus of the coat proteins, leaving a fully assembled virus particle composed of coat protein cores consisting of 216 or 218 amino acid residues. These core particles were indistinguishable from untreated native particles in an electron microscope and were still infectious. The core particles lacked the virus-specific surface epitopes that are recognized by the bulk of the polyclonal antibodies raised against the whole virus particles. Epitopes thought to be group-specific were located in the trypsin-resistant core protein region. The implications of these findings are discussed in relation to the similar surface location of the N- and C-terminal regions of the coat protein of other rod-shaped plant viruses and the observed common structural features displayed by isometric plant and animal viruses.

Differentiation of Potyviruses and Their Strains by High Performance Liquid Chromatographic Peptide Profiling of Coat Proteins

Summary Comparison by HPLC of tryptic digests of coat proteins from six biologically and serologically distinct potyviruses, namely bean yellow mosaic virus, Johnson grass mosaic virus, passion-fruit woodiness virus (PWV), potato virus Y (PVY), sugarcane mosaic virus (SCMV) and water-melon mosaic virus II, demonstrated that each potyvirus can be distinguished from the others. HPLC of tryptic peptides from coat proteins of four strains of PVY, two strains of PWV and three strains of SCMV showed that peptide patterns of strains from the same potyvirus were very similar. These findings were supported by amino-terminal amino acid sequence analysis of the peptides. The use of enzymes from different sources and variation in the temperature (35 °C to 40 °C) and time (16 to 20 h) of digestion caused small variations in the profiles but did not change the main features of the peptide patterns of each potyvirus. The results suggest that HPLC profiles of tryptic digests of the coat proteins of potyviruses could be useful criteria for the identification and classification of potyviruses.

Towards a system for the identification and classification of potyviruses: II. Virus particle length, symptomatology, and cytopathology of six distinct viruses

The mean particle lengths of lettuce mosaic virus (LMV), bean common mosaic virus (BCMV), passionfruit woodiness virus (PWV), potato virus Y (PVY), sugarcane mosaic virus (SCMV), and one strain of bean yellow mosaic virus (BYMV) were all shown to be close to 750 nm. However, the length of two other serologically closely related strains of BYMV, variants of pea mosaic virus referred to as PMV and SPMV, had significantly longer particles, about 792 and 842 nm. Each of the distinct viruses had readily distinguishable host ranges. The strains of BYMV could also be distinguished from each other although they had many hosts in common with similar symptoms. Electron microscopy of plant cells infected by the viruses studied showed that the cell inclusions induced by infection were of two readily distinguishable types although some minor virus-specific differences were also observed. The BYMV strains and LMV induced long “relaxed” pinwheel inclusions whereas those induced by BCMV, PWV, PVY, and SCMV were shorter, “tighter,” and curved. The significance of these observations to problems of potyvirus identification and classification is discussed.

Towards a system for the identification and classification of potyviruses: I. Serology and amino acid composition of six distinct viruses

Antigenic relationships of six distinct potyviruses were studied by immunodiffusion tests using highly purified sonicated virus preparations and anti-intact virus sera devoid of detectable antibodies to host-plant antigens. Three variants of bean yellow mosaic virus (BYMV) including BYMV sensu stricto and two variants of pea mosaic virus (PMV and SPMV) were shown to be antigenically very similar and also relatively closely related to lettuce mosaic virus (LMV). Distant antigenic relationships were detected between the BYMV variants and bean common mosaic virus (BCMV); between BCMV and passionfruit woodiness virus (PWV); and between PWV and potato virus Y (PVY). No antigenic relationships were detected between any of these viruses and sugarcane mosaic virus (SCMV). Antibodies in anti-viral sera were very poor in recognizing coat proteins dissociated with LiCl from homologous viruses and failed altogether to recognise those dissociated with pyrrolidine. Attempts to prepare antisera in mice against isolated viral coat proteins dissociated with either LiCl or pyrrolidine were unsuccessful due to poor immunogenicity of the preparations. Electrophoretic mobilities of the viral coat proteins relative to marker proteins in the presence of sodium dodecyl sulphate suggest that the protein subunits of all the viruses studied have molecular weights of about 33,000. However, the coat proteins were prone to partial degradation. The amino acid compositions of the antigenically closely related viruses were very similar, but similarities of those distantly related were no greater than those of the apparently unrelated viruses. The problems in the use of serological and amino acid composition data obtainable with currently available techniques for the classification of potyviruses are discussed.

The Distribution and Ultrastructural Effects of Passionfruit Woodiness Virus in Bean Leaves

An electron microscope examination was made of mesophyll cells in the leaves of French bean (Phaseolus vulgaris L.) cv. Cherokee Wax infected with passionfruit woodiness virus (PWV). Virus particles and virus-induced inclusions were found in the mesophyll cells of yellow areas of inoculated leaves, leaves with vein clearing, and yellow areas of leaves with systemic mosaic symptoms, but not in the green areas of inoculated leaves and only occasionally in dark green areas of leaves with systemic mosaic symptoms. Virus-induced inclusions were confined to the cytoplasm and were frequently associated with cell membranes. Chloroplasts in infected cells had an increased tendency to invagination of the limiting membranes, and the invaginated portion frequently contained a mitochondrion. Some effects were recorded on the numbers of starch grains per chloroplast.

Passiflora foetida, a whiespread host of passionfruit woodiness virus in Queensland.

Passiflora foetida, a whiespread host of passionfruit woodiness virus in Queensland.

A virus causing ringspot of Passiflora edulis in the Ivory Coast

SUMMARYA mechanically transmissible virus causing leaf mottling and ringspotting of Passiflora edulis var. flavicarpa in the Ivory Coast is described. Its particles are flexuous rods 810–830 nm long and 15 nm wide. It infects mainly species of Passifloraceae and Leguminosae; Passiflora foetida is a good diagnostic host. Aphis gossypii and Aphis spiraecola transmit the virus after brief acquisition feeds. Seed transmission was not detected. In crude sap of P. edulis, infectivity was lost after 10 min at 65–70 °C, 12–14 days at 24 °C or dilution to 10‐7. A purification method is described, using Triton‐X‐100 as clarifying agent. The virus is serologically related but not identical to passionfruit woodiness virus from Queensland. The virus seems to belong to the potato virus Y group and has the cryptogram */*:*/(6):E/E:S/Ap. It is designated passionfruit ringspot virus.

Two unrelated viruses which cause woodiness of passion fruit (Passiflora edulis Sims)

In Victoria cucumber mosaic virus (CMV) has been shown to be the cause of the woodiness disease of Passifloua edulis. This virus causes a slow decline of infected P. edulis seedlings, and a more rapid decline of vines grafted onto P. caerulea rootstocks. In Queensland a similar disease of passion fruit also occurs. The Queensland disease was shown to be caused by a virus which differed markedly from CMV, This virus, which is designated herein as passion fruit woodiness virus (PWV), has flexuous rod-shaped particles about 670 mµ in length. PWV was shown to be stylet-borne by the aphid Myzus persicae and to be transmitted to Phaseolus vulgaris and Sesbania exaltata by sap inoculation. The physical properties of PWV were determined, and two isolates of the virus were purified and antisera prepared against them.