Passion Fruit Woodiness Disease Research Articles

The Generation of Attenuated Mutants of East Asian Passiflora Virus via Deletion and Mutation in the N-Terminal Region of the HC-Pro Gene for Control through Cross-Protection.

East Asian Passiflora virus (EAPV) causes passionfruit woodiness disease, a major threat limiting passionfruit production in eastern Asia, including Taiwan and Vietnam. In this study, an infectious cDNA clone of a Taiwanese severe isolate EAPV-TW was tagged with a green fluorescent protein (GFP) reporter to monitor the virus in plants. Nicotiana benthamiana and yellow passionfruit plants inoculated with the construct showed typical symptoms of EAPV-TW. Based on our previous studies on pathogenicity determinants of potyviral HC-Pros, a deletion of six amino acids (d6) alone and its association with a point mutation (F8I, simplified as I8) were conducted in the N-terminal region of the HC-Pro gene of EAPV-TW to generate mutants of EAPV-d6 and EAPV-d6I8, respectively. The mutant EAPV-d6I8 caused infection without conspicuous symptoms in N. benthamiana and yellow passionfruit plants, while EAPV-d6 still induced slight leaf mottling. EAPV-d6I8 was stable after six passages under greenhouse conditions and displayed a zigzag pattern of virus accumulation, typical of a beneficial protective virus. The cross-protection effectiveness of EAPV-d6I8 was evaluated in both N. benthamiana and yellow passionfruit plants under greenhouse conditions. EAPV-d6I8 conferred complete cross-protection (100%) against the wild-type EAPV-TW-GFP in both N. benthamiana and yellow passionfruit plants, as verified by no severe symptoms, no fluorescent signals, and PCR-negative status for GFP. Furthermore, EAPV-d6I8 also provided complete protection against Vietnam's severe strain EAPV-GL1 in yellow passionfruit plants. Our results indicate that the attenuated mutant EAPV-d6I8 has great potential to control EAPV in Taiwan and Vietnam via cross-protection.

TaqMan real-time RT-PCR for detection of cowpea aphid-borne mosaic virus and epidemiological aspects of passion fruit woodiness disease

TaqMan real-time RT-PCR for detection of cowpea aphid-borne mosaic virus and epidemiological aspects of passion fruit woodiness disease

Occurrence of passion fruit woodiness disease in the coastal lowlands of Kenya and screening of passion fruit genotypes for resistance to passion fruit woodiness disease

BackgroundPassion fruit (Passiflora edulis [Sims]) is an important economic fruit crop in Kenya, grown for domestic, regional and international markets. However, passion fruit production is constrained by both biotic and abiotic stresses. Passion fruit woodiness disease (PWD) complex is the most injurious viral disease responsible for yield losses of up to 100%. In East Africa, it is caused by potyviruses. The most effective way to manage PWD is by using resistant cultivars. The objectives of this study were to determine the occurrence of passion fruit woodiness disease in selected counties at the Coastal lowlands of Kenya and screen farmer preferred passion fruit genotypes for resistance to PWD.ResultsIn the present study, it was established that all surveyed farms in Kwale and Kilifi counties displayed passion fruit woodiness virus disease symptoms. The highest disease incidence of 59.16% and 51.43% was observed at Kilifi and Kwale counties, respectively. A significant difference (p < 0.05) in symptom severity was observed within the tested genotypes with purple and banana passion fruits having the highest and lowest AUDPC values, respectively, both under greenhouse and field conditions. ACP ELISA assays using universal potyvirus antiserum (Agdia Inc., Elkhat, IN) confirmed that the observed characteristic symptoms of woodiness disease were as a result of potyvirus infection.ConclusionsThe findings herein indicate that PWD is widespread in both Kilifi and Kwale counties with low to moderate disease incidence and severity. The observed prevalence, incidence and severity levels of PWD in Kwale and Kilifi counties could be aggravated by poor management practices such as non-sterilization of pruning tools, intercropping with target crops and crop rotation with the same target crops. Response of passion fruit genotypes to woodiness viruses was genotype dependent. There is need to sensitize farmers on the cause and spread of PWD and management strategies in order to increase production and enhance the quality of fruits.

Generation of Attenuated Passiflora Mottle Virus Through Modification of the Helper Component Protease for Cross Protection.

Passiflora mottle virus (PaMoV), an aphid-borne potyvirus, is the primary causal virus of devastating passionfruit woodiness disease in Vietnam. Here we generated a nonpathogenic, attenuated PaMoV strain for disease control by cross protection. A full-length genomic cDNA of PaMoV strain DN4 from Vietnam was constructed to generate an infectious clone. The green fluorescent protein was tagged at the N-terminal region of the coat protein gene to monitor in planta the severe PaMoV-DN4. Two amino acids within the conserved motifs of helper component protease (HC-Pro) of PaMoV-DN4 were mutated individually or in combination as K53E or/and R181I. Mutants PaMoV-E53 and PaMoV-I181 induced local lesions in Chenopodium quinoa plants, while PaMoV-E53I181 caused infection without apparent symptoms. In passionfruit (Passiflora edulis) plants, PaMoV-E53 elicited severe leaf mosaic and PaMoV-I181 induced leaf mottling, while PaMoV-E53I181 caused transient mottling followed by symptomless recovery. PaMoV-E53I181 was stable after six serial passages in yellow passionfruit (Passiflora edulis f. flavicarpa) plants. Its temporal accumulation levels were lower than those of the wild type, with a zigzag accumulation pattern, typical of a beneficial protective virus. An RNA silencing suppression (RSS) assay revealed that all three mutated HC-Pros are defective in RSS. Triplicated cross-protection experiments with a total of 45 plants showed that the attenuated mutant PaMoV-E53I181 provided a high protection rate (91%) against the homologous wild-type virus in passionfruit plants. This work revealed that PaMoV-E53I181 can be used as a protective virus to control PaMoV by cross protection.

Passion fruit woodiness virus (passionfruit woodiness disease)

Passion fruit woodiness virus (passionfruit woodiness disease)

Metabolomic and Histological Response of Passiflora cincinnata Infected with Cowpea aphid-borne mosaic virus (CABMV) Reveals Changes in Asymptomatic and Symptomatic Phases

Passion fruit woodiness disease, caused by the Cowpea aphid-borne mosaic virus (CABMV), is one of the leading phytosanitary challenges of passion fruit production. Passiflora cincinnata has been recognized for its potential in genetic improvement due to its highest resistance to CABMV and other phytopathogens. Metabolomic and histological alterations of P. cincinnata infected with CABMV were evaluated and searched for differential responses during the asymptomatic or symptomatic infection phases to correlate them with the mechanisms of metabolic defense. The metabolites of infected plants were analyzed by liquid chromatography-mass spectrometry. Based on the metabolomic profile, the times of infection were grouped into early or late infection phases. The metabolites related to CABMV infection were classified as alkaloids, saponins, phospholipids and acids. This study can assist agricultural institutions or farms in the early diagnosis and correct management of CABMV infection and contribute to the genetic improvement of the Passiflora genus against this disease.

A fungal glycoprotein mitigates passion fruit woodiness disease caused by Cowpea aphid-borne mosaic virus (CABMV) in Passiflora edulis

A fungal glycoprotein mitigates passion fruit woodiness disease caused by Cowpea aphid-borne mosaic virus (CABMV) in Passiflora edulis

Characterization and Detection of Passiflora Mottle Virus and Two Other Potyviruses Causing Passionfruit Woodiness Disease in Vietnam.

Passionfruit plantings in Vietnam increased to 10,000 ha in 2019. However, outbreaks of passionfruit woodiness disease (PWD) have become a serious threat to production. In this study, five virus isolates (DN1, DN4, NA1, GL1, and GL2) were collected from different areas of Vietnam. Their causal roles in PWD were verified by back-inoculation to passionfruit. Analyses of coat protein (CP) and genomic sequences revealed that the GL1 isolate is closely related to East Asia Passiflora virus (EAPV) AO strain of Japan (polyprotein nt and aa identities of 98.1 and 98.2%, respectively), and the GL2 isolate is related to Telosma mosaic virus (TelMV) isolate PasFru, China (polyprotein nt and aa identities of 87.1 and 90.9%, respectively). CP comparison, host range, and cytological characterization indicated that DN1, DN4, and NA1 are potyviruses but are different from EAPV and TelMV. Phylogenic analyses of their CP and genome sequences indicated that these three isolates and the passionfruit severe mottle-associated virus Fujian isolate of China belong to a distinct clade, which does not meet the threshold (76% nt identity of polyprotein) to be regarded as any of potyviral species. Thus, a new species name, Passiflora mottle virus, (PaMoV), has been proposed by the International Committee on Taxonomy of Viruses. A rabbit antiserum was produced against the CP of DN1, and it can distinguish PaMoV from TelMV and EAPV in western blotting and enzyme-linked immunosorbent assay (ELISA) without cross-reactions. Field surveys of 240 samples by ELISA and reverse transcription PCR found that PWD in Vietnam is caused mainly by PaMoV, followed by EAPV, mixed infection of PaMoV and EAPV, and rare cases of TelMV.

Responses of Passiflora spp. to cowpea aphid-borne mosaic virus reveal infection in asymptomatic plants and new species with probable immunity.

Passion fruit woodiness disease (PWD), caused by cowpea aphid-borne mosaic virus (CABMV), produces socioeconomic problems in Brazil. The objectives of this study were to i) evaluate the temporal progression of PWD, ii) identify Passiflora genotypes with resistance to CABMV, and iii) detect virus infection in asymptomatic plants by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in cases where standard RT-PCR detection failed. The experiment was conducted in a greenhouse using 128 genotypes belonging to 12 species and three hybrids (inter- and intraspecific) of Passiflora, evaluated at five time points after inoculation. Progression rates and disease severity were lower in P. cincinnata, P. gibertii, P. miersii, and P. mucronata than in P. edulis, P. alata, Passiflora sp., and hybrids. Of the genotypes tested, 20.31% were resistant, especially the accessions of P. suberosa, P. malacophylla, P. setacea, P. pohlii, and P. bahiensis, which remained asymptomatic throughout the experiment. The absence of symptoms does not imply immunity of plants to the virus, since RT-qPCR analysis confirmed infection by the virus in asymptomatic plants of P. cincinnata, P. gibertii, P. miersii, P. mucronata, P. setacea, P. malacophylla, and P. suberosa. Even after four inoculations, the virus was not detected by RT-qPCR in the upper leaves in plants of the species P. pohlii and P. bahiensis, indicating that these species are probably immune to CABMV.

Occurrence of the Cowpea aphid-borne mosaic virus in Jataí, Brazil

The objective was to characterize the introduction of the passion fruit woodiness disease in plants and fruits of passion fruit in Jatai - GO. Plants of passion fruit showed the symptoms of the virus at the end of the first year in the field. Infection was confirmed by serological analysis using the PTA ELISA indirect test. This report will contribute to the information already known about this disease, and will serve as a basis for passion fruit producers to identify symptoms in plants affected with the virus.

How segregating populations of passion fruit react to CABMV infection?

The passion fruit woodiness disease, caused by the cowpea aphid-borne mosaic virus (CABMV), is the most important disease and represents a limiting factor for culture. Cultivars with resistance levels are being developed from backcrosses associated with a recurrent selection program. Studies showing how segregating populations respond to infection over time and describing resistance are necessary and make it possible to characterize the genotypes and select the most promising ones. Therefore, the present study aimed to describe the pathogenesis; evaluate resistance in the Passiflora sp. × CABMV pathosystem; and select the most resistant individuals for generation advance in the recurrent selection program in passion fruit. Five generations of crossbreeding were used, namely, interspecific hybrid, backcrosses BC1.1 and BC1.2 and parents P. edulis and P. setacea. The plants were inoculated in a greenhouse and evaluated for resistance to CABMV. The area under the disease progress curve (AUDPC) was calculated and variance components and genetic values were estimated for the populations under study. High genetic variability was observed between the individuals, ranging from asymptomatic plants to plants exhibiting the most severe symptoms of the disease. Four phenotypic groups were formed, allowing greater differentiation between the generations and their parents. The presence of CABMV was confirmed in plants of the BC1.1 generation and of P. edulis, with characteristic symptoms of the virus. In asymptomatic plants, 75% of the individuals were considered resistant by PTA-ELISA and RT-PCR. The majority of individuals selected for resistance to CABMV belonged to the BC1.2 generation, which might thus be included in the recurrent selection program.

Unlikely transmission of Cowpea aphid-borne mosaic virus by hand pollination of passionflower

Passion fruit plants are self-incompatible and fruiting is exclusively dependent on cross-pollination, which in nature is performed by carpenter (mamangava) bees, especially Xylocopa spp. (family Apidae). To ensure satisfactory productivity, daily manual pollination is a common practice among passionflower growers. Therefore, we studied whether manual pollination mechanically transmits the cowpea aphid-borne mosaic virus (CABMV), the causal agent of the passion fruit woodiness disease. None of the eight healthy passion fruit plants manually pollinated with pollen from CABMV field-infected plants were infected, as confirmed by PTA-ELISA and RT-PCR. Healthy passion fruit plants mechanically inoculated with extracts of pollen collected from flowers of CABMV field-infected plants were not infected. CABMV was only detected by RT-PCR in groups of three anthers, and in pollen from groups of 20 anthers collected from flowers of infected passion fruit plants. RT-qPCR conducted with different amounts of pollen grains and anthers indicated extremely low virus titers. In addition to low virus titers, transmission failure may be associated with an absence of virus particles outside the pollen grains and/or absence of enough wounding produced on the stigmas by the fingertips. The improbability of CABMV transmission via pollen during manual pollination showed that this widely used cultural practice is a negligible factor in the epidemiology of passion fruit woodiness disease.

Prospecting on Passiflora backcross families: implications for breeding aiming at CABMV resistance

Passion fruit woodiness disease induced by Cowpea aphid-borne mosaic virus (CABMV) is currently the most harmful viral disease affecting passion fruit crops. Given the economic importance of this fruit crop in Brazil, it is essential that passion fruit breeding programs invest in developing resistant and productive cultivars. The goals of this study were to estimate genetic parameters of agronomic and resistance traits via restricted maximum likelihood (REML) and select individuals found to be resistant to CABMV and agronomically superior, in order to provide the basis for further studies on passion fruit breeding, with the aim to develop cultivars resistant to CABMV. The study was conducted in randomized block design, with four replicates. Three full-sib families from the recombination of RC1 parents were evaluated. Based on the severity data, the area below the mean disease progress curve (AUDPCM) was estimated. Five traits relating to fruit yield and quality were also assessed. The components of variance and genetic values were estimated by the REML/best linear unbiased prediction (BLUP) mixed model methodology. A difference in the severity of CABMV symptoms was recorded among the 119 genotypes evaluated. AUDPCM values varied from 750 to 1252.5 for individuals 202 and 161, respectively. Family 1 distinguished itself with the largest number of individuals selected for resistance; for agronomic traits, families 1 and 2 contributed most of the selected genotypes. Genotypes 167, 24, 34, 23 and 202 achieved the lowest AUDPCM values, being selected for most of the agronomic traits; these results indicate the potential of these genotypes to be chosen and recombined for the advancement of generations in breeding programs aimed at developing resistance to CABMV. The strategy of recombining resistant genotypes from RC1 populations appears to be promising for breeding for resistance to CABMV, of which the heritability is complex.

Field assessment of a second generation backcross (BC1 × Passiflora edulis) of passion fruit for agronomic performance and resistance to CABMV

AbstractThe objective of this work was to characterize and identify among the passion fruit hybrids of the second generation backcross (BC2: BC1 × P. edulis), resistance to passion fruit woodiness disease (CABMV) with desirable agronomic attributes. Ninety‐two progeny of BC2 hybrids were evaluated for severity of the virus in conditions of field, physical and chemical characterization of the fruits and precocity of the plant in relation to the vegetative and reproductive phases. The data were analysed using multivariate statistics and mixed models (REML/BLUP) to estimate genetic parameters. The was conditioned by and , for number of fruits, fruit and peel weight and soluble solids and the effect of for virus severity to CABMV and effect of on the variables fruit length, fruit diameter, peel thickness and pulp weight. For the titratable acidity it had no . The progeny BC2‐A, BC2‐C, BC2‐E, BC2‐F and BC2‐H families can be selected for use in passion fruit breeding programmes by adding high vegetative vigour, early fruit production, resistance to CABMV and also desirable agronomic attributes.

Interaction between Cowpea Aphid-Borne Mosaic Virus Isolates and Its Effect on Passion Fruit Woodiness Disease on Passiflora edulis Sims and Passiflora ligularis Juss

In East Africa, passion fruit woodiness disease is caused by potyviruses, among which are Cowpea Aphid-Borne Mosaic Virus (CABMV) and Uganda Passiflora Virus (UPV). Previous studies suggest that synergistic interaction of viruses causes mild or severe outcomes of the disease. However, mixed infections of these viruses have not been documented. The aim of this study was to determine the effects of the interaction between two CABMV isolates causing passion fruit woodiness disease in Kenya. Healthy plants were mechanically inoculated at six-leaf stage. Four treatments were used: CABMV isolate 1, CABMV isolate 2, mixture of the two isolates, and noninoculated control. The test plants were maintained in a screen house, and data on symptom severity and rate of disease development were recorded. ELISA test was conducted to confirm virus presence and distribution. The results indicate that the CABMV isolates used are systemic. There were various differences in disease progression, which was faster in the sweet passion variety than in the purple variety. However, the latter had a higher disease severity. Coinfected plants expressed severe symptoms compared to the singly infected ones, indicating synergistic interaction between the viral isolates. This implies that coinfection has adverse impact resulting in higher economic losses.

Screening of Sour Passion Fruit for Reaction to Bacterial Spot and Passion Fruit Woodiness Disease

The development of resistant varieties is a promising strategy for bacterial spot disease (Xanthomonas axonopodis pv. passiflorae-Xap) and passion fruit woodiness disease (PWD; Cowpea aphid-borne mosaic virus-CABMV) control in sour passion fruit (Passiflora edulis Sims). This study aimed at evaluating the reaction of 12 sour passion fruit half-sib progenies to both mechanically inoculated Xap and CABMV, under protected cultivation. The bacterial spot and PWD severity degrees observed reveal the existence of variability within progenies. MAR20#2005 and BRS GA1 revealed the lowest bacterial disease severity scores while MAR20#41, MAR20#2005, and Rosa Intenso 1 showed the lowest PWD severity scores. MAR20#41 presented the lowest disease incidence in all evaluations, demonstrating a slow increase in the number of plants with symptoms over time. Also, MAR20#41 stood out as the progeny with the greatest number of plants presenting resistance to PWD at the end of the study. Among the progenies selected, MAR20#2005 was the most promising for presenting the lowest severity scores for both bacterial spot and PWD.

Long‐lasting systematic roguing for effective management of CABMV in passion flower orchards through maintenance of separated plants

In Brazil, passion flower is grown across almost the entire country. The predominant disease of the passion flower crop is passion fruit woodiness, caused by the potyvirus cowpea aphid‐borne mosaic virus (CABMV), and transmitted by aphids in a nonpersistent manner. The disease reduces the useful life of the orchard from 36 months to approximately 18 months. Up to now, there has not been an efficient method for disease management. The aim of this work was to evaluate the efficiency of systematic roguing of diseased plants through weekly inspections, for disease management in the field. The latent and incubation periods of CABMV in passion flower vines were determined in order to optimize roguing efficiency. Passion fruit plants inoculated with CABMV started to act as sources of inoculum from 3 days after inoculation (DAI), and the symptoms were expressed, on average, at 8 DAI. Five field experiments, conducted in the states of São Paulo and Bahia, Brazil, demonstrated that systematic roguing of diseased plants was significantly efficient for managing passion fruit woodiness disease. In order to facilitate identification and subsequent removal of the infected plants, they need to be grown separately. This cultural practice can be recommended for managing passion fruit woodiness disease, provided it is applied on a regional scale by all passion fruit growers. The development of some pilot plantings for the application of roguing in a passion flower‐producing region is recommended to validate the use of this technique for managing passion fruit woodiness disease.

Illumina Sequencing Reveals the First Near-Complete Genome Sequence of Ugandan Passiflora Virus.

Here, we present the first near-complete genome of Ugandan Passiflora virus (UPV) sequenced from a symptomatic sample of KH7 passion fruit (Passiflora edulis Sims) variety. UPV had limited amino acid identity with other potyviruses known to cause passion fruit woodiness disease (PWD). The closest relationship (71.2% amino acid similarity) was with Bean common mosaic necrosis virus.

Yellow passion fruit reaction to Xanthomonas axonopodis pv. passiflorae and to Cowpea aphid-borne mosaic virus

Yellow passion fruit (Passiflora edulis Sims) yield and longevity have been drastically reduced by bacterial spot (Xanthomonas axonopodis pv. passiflorae - Xap) and passion fruit woodiness disease (PWD) (Cowpea aphid-borne mosaic virus - CABMV). This study was aimed at evaluating the reaction of 11 genotypes of yellow passion fruit, based on the reaction of their progenies, to both mechanically inoculated Xap and CABMV, under greenhouse conditions. There was a progressive increase in bacterial spot and PWD severity with time. BRS Gigante Amarelo, MAR20#12, and MAR20#34 were selected as the progenies with lowest bacterial spot severity and disease progress over time. MAR20#2005, EC-L-7, UnB2015-1, and EC-3-0 presented the lowest PWD severity and disease progress over time. These progenies, along with individual plants from other progenies in which disease severity was significantly low until the last evaluation, will be cloned and tested again for Xap and CABMV, including other isolates.

The virus causing passionfruit woodiness disease in Taiwan is reclassified as East Asian passiflora virus

Based on filamentous particles, aphid transmission, and symptoms of distorted, size-reduced, woody fruits, the major potyvirus associated with passionfruit woodiness disease (PWD) in Taiwan has been regarded as Passionfruit woodiness virus (PWV) for decades. In this study, the genomes of four potyvirus isolates, originally collected from orchards with PWD in Taiwan and re-designated as Poty-TW, Poty-0920-6, Poty-dpd and Poty-pt, were sequenced for molecular characterization. Our results revealed that the CP genes of Poty-TW and Poty-0920-6 share nucleotide (nt) identities/amino acid (aa) identities of 97.7/95.9 and 98.5/97.2%, respectively, with that of East Asian passiflora virus (EAPV) isolate AO of Japan, and the CP genes of Poty-dpd and Poty-pt share nt/aa identities of 95.3/96.2 and 94.9/97.6% respectively, with that of EAPV isolate IB of Japan. The genomic sequences of PWD-associate viruses in Taiwan also share high degrees of homology with that of EAPV-AO (TW and 0920-6 isolates > 98%) and EAPV-IB (dpd and pt isolates > 88%). However, the CP genes of four PWD-associated viruses from Taiwan share only 67.6–69.4% nt identities with that of PWV Australia MU isolate, does not satisfy the ICTV criteria (> 76%) to be regarded as a strain of PWV. A field survey with 175 samples from different areas of Taiwan demonstrated that the PWD-associated potyvirus is mainly caused by EAPV. Hence, our results indicate that the major potyvirus causing PWD in Taiwan should be reclassified as EAPV.