scholarly journals Endemic Atlantic Forest species of Caryophyllales as inhibitors of viral infection in zucchini

2021 ◽  
Vol 39 (2) ◽  
pp. 146-154
Author(s):  
Marcos Vinicius M Pereira ◽  
Maria Amélia V Alexandre ◽  
Alexandre Levi R Chaves ◽  
Ana Cláudia O de Souza ◽  
Luís Carlos Bernacci ◽  
...  

ABSTRACT In Brazil, zucchini (Cucurbita pepo) is a socioeconomically important vegetable affected by damage caused primarily by zucchini yellow mosaic virus (ZYMV). Although the occurrence of cucumber mosaic virus (CMV) is less frequent, in C. pepo ‘Caserta’ plants it can cause symptoms such as mottle, mosaic, leaf and fruit distortion, as well as reduced plant development. To minimize the damage, the most widely used management technique is the preventive, albeit inefficient, application of insecticides, aimed at controlling aphids, the vectors of this virus. Thus, the search for more effective and less environmentally harmful control methods has been the target of investigations. The purpose of the present study was to assess the action of the extracts of four native Caryophyllales species, as inhibitors of infection by CMV and ZYMV in C. pepo, in addition to evaluating the possible induced resistance in this species. Fresh leaf extracts (LEs) of Guapira opposita, Pisonia ambigua (Nyctaginaceae), Gallesia integrifolia and Seguieria langsdorffii (Phytolaccaceae), previously assessed in the tobacco mosaic virus / Nicotiana glutinosa pathosystem, were submitted to progressive dilutions sprayed on cotyledonary C. pepo leaves 30 min before inoculation with CMV and ZYMV. Leaf extracts of G. integrifolia did not induce inhibition in any of the pathosystems assessed. Guapira opposita LEs inhibited the infection of plants inoculated with ZYMV below 50% but inhibited CMV infection by 70% at a concentration of 1:40. Given that leaf extracts of P. ambigua and S. langsdorffii induced high percentage inhibition, evident in the number of asymptomatic plants and confirmed by serological tests, these species were selected to assess induced resistance in pre-treatment experiments. The LEs were efficient in inhibiting ZYMV and CMV infection in C. pepo when applied up to 48 h before inoculation. The LEs of S. langsdorffii and G. opposita, also tested for this system, were efficient when applied up to 72 h before CMV inoculation. The LEs can be prepared from dry leaves and maintained at -20°C for at least three years, conserving their inhibitory activity. These results expand the possibilities for producers and consumers alike in the sustainable management of the main zucchini viruses, without damaging the environment.

Plant Disease ◽  
1998 ◽  
Vol 82 (5) ◽  
pp. 475-478 ◽  
Author(s):  
A. A. Zouba ◽  
M. V. Lopez ◽  
H. Anger

A severe yellow and leaf curl disease affecting field squash was found in the Batinah region of the Sultanate of Oman. The symptoms appear as small yellow spots, diffuse veinal yellowing, and leaf curling of young leaves. The inciting virus was easily transmitted by mechanical inoculation and by the whitefly Bemisia tabaci in a semi-persistent manner. The host range of the virus was restricted to two cucurbit species. Leaf dip preparations contained few flexuous particles about 700 to 750 nm long. Pinwheel-like inclusion bodies were observed in thin sections of diseased squash tissues. Serological tests by enzyme-linked immunosorbent assay showed that the virus is serologically related to watermelon mosaic virus-2, but not to zucchini yellow mosaic virus or papaya ring spot virus (watermelon strain). In view of these properties, this virus is considered to be a newly described virus and is tentatively named squash yellow leaf curl virus.


Author(s):  
Igor Forigo Beloti ◽  
Gabriel Mascarenhas Maciel ◽  
Igor Matheus Alves ◽  
Lucas Medeiros Pereira ◽  
Ernane Miranda Lemes

Zucchini (Cucurbita pepo L.) is a horticultural plant species of great socioeconomic value in tropical countries such as Colombia and Brazil. The production of zucchini is qualitatively and quantitatively affected by many diseases, especially viruses belonging to the Potyvirus (Zucchini yellow mosaic virus - ZYMV) and Comovirus (Squash mosaic virus - SqMV) groups. The primary strategy to reduce the spread of potentially damaging plant viruses is the development of genotypes with genetic tolerance; however, there are not many zucchini genotypes with multiple tolerance. Therefore, this study evaluated 66 zucchini genotypes to find sources of tolerance to the ZYMV and SqMV viruses. This experiment was conducted in a completely randomized design using genotypes from the germplasm bank of the Federal University of Uberlândia, including the genotypes: Emanuela (common commercial genotype) ‘Tronco Caserta’ (susceptible genotype) and PX 13067051 (resistant genotype). Leaf extracts containing viral particles were used as inoculant, and the distribution of grades of tolerance was recorded at the seedling stage. The lineages UFU-C×UFU-A#18#3;1, UFU-C×UFU-F#19#11;3, UFU-F#4#9;1, and UFU-D×UFU-F#7#21;1 and the Emanuela cultivar are alternatives for the production of new zucchini genotypes or hybrids with tolerance to the viruses ZYMV and SqMV. More severe symptoms were observed, as well as a larger number of susceptible genotypes for the ZYMV virus, indicating that this virus has great potential for causing damage and losses to zucchini crops.


2016 ◽  
Vol 53 (01) ◽  
pp. 187-194
Author(s):  
Ummad-ud-Din Umar ◽  
Syed Atif Hasan Naqvi ◽  
Azhar Ali Khan ◽  
Ateeq-ur Rehman ◽  
Rashida Parveen ◽  
...  

2007 ◽  
Vol 87 (3) ◽  
pp. 123-130 ◽  
Author(s):  
Gassan Köklü ◽  
Özgür Yilmaz

Abstract A survey for the detection of cucumber mosaic virus (CMV), papaya ringspot virus-W (PRSV-W), squash mosaic virus (SqMV), melon necrotic spot virus (MNSV), cucumber green mottle mosaic virus (CGMMV), zucchini yellow mosaic virus (ZYMV) and watermelon mosaic virus-2 (WMV-2) was carried out in June and July 2005, covering 17 melon fields and 19 watermelon fields in the Tekirdag, Edirne and Kırklareli provinces of Turkish Thrace. Among all the fields sampled, only one melon field was not virus-infected. In all, 502 melon and watermelon samples were tested for the presence of seven viruses with ELISA tests using polyclonal antisera. Overall, 333 out of 502 samples tested positive for the investigated viruses: 167 out of 235 plant samples in Tekirdag, 103 out of 187 samples in Edirne, and 63 out of 80 samples in Kırklareli were positive. Serological tests showed that six out of the seven tested viruses were present in the Thrace region of Turkey. The following rates of incidence of tested viruses on watermelon were found: ZYMV (45.5%), WMV-2 (34.2%), CMV (19.9%), PRSV-W (2.1%), SqMV (1.8%) and MNSV (0.4%), while the rates of incidence on melon were ZYMV (40.3%), WMV-2 (31.2%), CMV (7.2%), PRSV-W (2.3%), SqMV (0.5%) and MNSV (1.8%). The WMV-2+ZYMV mixed infection type was the most widespread both on melon and on watermelon samples at 16.7% and 11.4%, respectively.


2019 ◽  
pp. 1409-1415
Author(s):  
Gerffeson Thiago Mota de Almeida Silva ◽  
José Albérsio de Araújo Lima ◽  
Graziela da Silva Barbosa ◽  
Ênio Gomes Flôr Souza ◽  
Giordanio Bruno Silva Oliveira ◽  
...  

We used 19 genotypes (plus controls) of watermelon from the collection of Cucurbitaceas germplasm of the Federal Rural University of the Semi-Arid to select watermelon plants resistant to Papaya ringspot virus “type Watermelon” (PRSV-W), Watermelon mosaic virus (WMV), and Zucchini yellow mosaic virus (ZYMV). Twenty individual plants were tested for each genotype/accession. Three controls were also used (3 genotypes). Evaluations were performed under greenhouse in a completely randomized design with five replications. The first inoculation was performed on the seedlings before the appearance of the first definitive leaf. From each accession (genotype) 20 different individual plants were inoculated with the three viruses. The inoculum was prepared by infected leaf tissue. The viral suspension and gauze soaked in extract were wiped on the surface of the leaves. Ten days later, the symptom assessment was performed. Subsequently, the plants were individually tested against the specific viruses using indirect ELISA. ELISA negative plants were submitted to a second inoculation under greenhouse, as described for the first inoculation. Ten days after new inoculation, new symptomatological evaluations and serological tests were performed to confirm the resistance of the plants. Plants that were negative by ELISA were tested by RT-PCR for confirmation of resistance. Resistance to the three viruses was verified individually in several tested genotypes. We found resistance to the three viruses tested, but in different plant individuals, where 16 individual plants were WMV-resistant, 26 PRSV-W resistant and 30 ZYMV-resistant. These plants can be used to develop homozygous lines for resistance to the virus studied.


Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 53
Author(s):  
Vivek Khanal ◽  
Harrington Wells ◽  
Akhtar Ali

Field information about viruses infecting crops is fundamental for understanding the severity of the effects they cause in plants. To determine the status of cucurbit viruses, surveys were conducted for three consecutive years (2016–2018) in different agricultural districts of Oklahoma. A total of 1331 leaf samples from >90 fields were randomly collected from both symptomatic and asymptomatic cucurbit plants across 11 counties. All samples were tested with the dot-immunobinding assay (DIBA) against the antisera of 10 known viruses. Samples infected with papaya ringspot virus (PRSV-W), watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV), and cucurbit aphid-borne-yellows virus (CABYV) were also tested by RT-PCR. Of the 10 viruses, PRSV-W was the most widespread, with an overall prevalence of 59.1%, present in all 11 counties, followed by ZYMV (27.6%), in 10 counties, and WMV (20.7%), in seven counties, while the remaining viruses were present sporadically with low incidence. Approximately 42% of the infected samples were positive, with more than one virus indicating a high proportion of mixed infections. CABYV was detected for the first time in Oklahoma, and the phylogenetic analysis of the first complete genome sequence of a CABYV isolate (BL-4) from the US showed a close relationship with Asian isolates.


2003 ◽  
Vol 93 (12) ◽  
pp. 1478-1484 ◽  
Author(s):  
C. Desbiez ◽  
A. Gal-On ◽  
M. Girard ◽  
C. Wipf-Scheibel ◽  
H. Lecoq

Zucchini yellow mosaic virus (ZYMV, Potyvirus) is a very damaging cucurbit virus worldwide. Interspecific crosses with resistant Cucurbita moschata have led to the release of “resistant” zucchini squash (C. pepo) F1 hybrids. However, although the resistance is almost complete in C. moschata, the commercial C. pepo hybrids are only tolerant. ZYMV evolution toward increased aggressiveness on tolerant hybrids was observed in the field and was obtained experimentally. Sequence comparisons and recombination experiments revealed that a point mutation in the P3 protein of ZYMV was enough to induce tolerance breaking. Competition experiments were performed between quasi-isogenic wild-type, and aggressive variants of ZYMV distinguished by monoclonal antibodies. The aggressive mutants were more fit than wild-type strains in mixed infections of tolerant zucchini, but they presented a drastic fitness loss in mixed infections of susceptible zucchini or melon. Thus, the ability to induce severe symptoms in tolerant zucchini is related to a genetic load in susceptible zucchini, but also on other susceptible hosts. This represents the first quantitative study of the fitness cost associated with tolerance breaking for a plant virus. Thus, although easily broken, the tolerance might prove durable in some conditions if the aggressive variants are counterselected in susceptible crops.


Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1326-1336 ◽  
Author(s):  
Solomon Maina ◽  
Martin J. Barbetti ◽  
Owain R. Edwards ◽  
David Minemba ◽  
Michael W. Areke ◽  
...  

Zucchini yellow mosaic virus (ZYMV) isolates were obtained in Papua New Guinea (PNG) from cucumber (Cucumis sativus) or pumpkin (Cucurbita spp.) plants showing mosaic symptoms growing at Kongop in the Mount Hagen District, Western Highlands Province, or Zage in the Goroka District, Eastern Highlands Province. The samples were blotted onto FTA cards, which were sent to Australia, where they were subjected to high-throughput sequencing. When the coding regions of the nine new ZYMV genomic sequences found were compared with those of 64 other ZYMV sequences from elsewhere, they grouped together, forming new minor phylogroup VII within ZYMV’s major phylogroup A. Genetic connectivity was lacking between ZYMV genomic sequences from PNG and its neighboring countries, Australia and East Timor; the closest match between a PNG and any other genomic sequence was a 92.8% nucleotide identity with a sequence in major phylogroup A’s minor phylogroup VI from Japan. When the RDP5.2 recombination analysis program was used to compare 66 ZYMV sequences, evidence was obtained of 30 firm recombination events involving 41 sequences, and all isolates from PNG were recombinants. There were 21 sequences without recombination events in major phylogroup A, whereas there were only 4 such sequences within major phylogroup B. ZYMV’s P1, Cl, N1a-Pro, P3, CP, and NIb regions contained the highest evidence of recombination breakpoints. Following removal of recombinant sequences, seven minor phylogroups were absent (I, III, IV, V, VI, VII, and VIII), leaving only minor phylogroups II and IX. By contrast, when a phylogenetic tree was constructed using recombinant sequences with their recombinationally derived tracts removed before analysis, five previous minor phylogroups remained unchanged within major phylogroup A (II, III, IV, V, and VII) while four formed two new merged phylogroups (I/VI and VIII/IX). Absence of genetic connectivity between PNG, Australian, and East Timorese ZYMV sequences, and the 92.8% nucleotide identity between a PNG sequence and the closest sequence from elsewhere, suggest that a single introduction may have occurred followed by subsequent evolution to adapt to the PNG environment. The need for enhanced biosecurity measures to protect against potentially damaging virus movements crossing the seas separating neighboring countries in this region of the world is discussed.


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