Effects of an alphasatellite on life cycle of the nanovirus Faba bean necrotic yellows virus

2021 ◽  
Author(s):  
Mahsa Mansourpour ◽  
Romain Gallet ◽  
Alireza Abbasi ◽  
Stephane Blanc ◽  
Akbar Dizadji ◽  
...  
Keyword(s):  
Host Plant ◽  
Faba Bean ◽  
Acyrthosiphon Pisum ◽  
Subterranean Clover ◽  
Plant Viruses ◽  
Single Stranded Dna ◽  
Virus Load ◽  
Aphid Vector ◽  
The Impact ◽  
Viral Accumulation

Nanoviruses are plant viruses with a multipartite single-stranded DNA (ssDNA) genome. Alphasatellites are commonly associated with nanovirus infections, but their putative impact on their helper viruses is unknown. In this study, we investigated the role of subterranean clover stunt alphasatellite 1 (hereafter named SCSA 1) on various important traits of faba bean necrotic yellows virus (FBNYV) in its host plant Vicia faba and aphid vector Acyrthosiphon pisum , including disease symptoms, viral accumulation and transmission. The results indicate that SCSA 1 does not affect the symptom severity nor the overall FBNYV accumulation in V. faba, but changes the relative amounts of its different genomic segments. Moreover, the association of SCSA 1 with FBNYV increases the rate of plant-to-plant transmission by a process seemingly unrelated to simple increase of the viral accumulation in the vector. These results represent the first study on the impact of an alphasatellite on the biology of its helper nanovirus. They suggest that SCSA 1 may benefit FBNYV, but the genericity of this conclusion is discussed and questioned. Importance Alphasatellites are circular single stranded DNA molecules frequently found in association with natural isolates of nanoviruses and some geminiviruse, the two ssDNA plant infecting virus families. While the implications of alphasatellite presence in geminivirus infections are relatively well documented, comparable studies on alphasatellites associated with nanoviruses are not available. Here we confirm that subterranean clover stunt alphasatellite 1 affects different traits of its helper nanovirus, faba bean necrotic yellows virus, both in the host plant and aphid vector. We show that the frequencies of the virus segments change in the presence of alphasatellite, in both plant and vector. We also confirm that while within-plant virus load and symptom are not affected by alphasatellite, the presence of alphasatellite decreases within-aphid virus load, but significantly increases virus transmission rate, so may confer a possible evolutionary advantage for the helper virus.

scholarly journals Circulative Nonpropagative Aphid Transmission of Nanoviruses: an Oversimplified View

2015 ◽  
Vol 89 (19) ◽  
pp. 9719-9726 ◽  
Author(s):  
Anne Sicard ◽  
Jean-Louis Zeddam ◽  
Michel Yvon ◽  
Yannis Michalakis ◽  
Serafin Gutiérrez ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Faba Bean ◽  
Plant Viruses ◽  
The Body ◽  
Virus Species ◽  
Content Type ◽  
Aphid Vector ◽  
Arthropod Vectors ◽  
The Family ◽  
Aphid Vectors

ABSTRACTPlant virus species of the familyNanoviridaehave segmented genomes with the highest known number of segments encapsidated individually. They thus likely represent the most extreme case of the so-called multipartite, or multicomponent, viruses. All species of the family are believed to be transmitted in a circulative nonpropagative manner by aphid vectors, meaning that the virus simply crosses cellular barriers within the aphid body, from the gut to the salivary glands, without replicating or even expressing any of its genes. However, this assumption is largely based on analogy with the transmission of other plant viruses, such as geminiviruses or luteoviruses, and the details of the molecular and cellular interactions between aphids and nanoviruses are poorly investigated. When comparing the relative frequencies of the eight genome segments in populations of the speciesFaba bean necrotic stunt virus(FBNSV) (genusNanovirus) within host plants and within aphid vectors fed on these plants, we unexpectedly found evidence of reproducible changes in the frequencies of some specific segments. We further show that these changes occur within the gut during early stages of the virus cycle in the aphid and not later, when the virus is translocated into the salivary glands. This peculiar observation, which was similarly confirmed in three aphid vector species,Acyrthosiphon pisum,Aphis craccivora, andMyzus persicae, calls for revisiting of the mechanisms of nanovirus transmission. It reveals an unexpected intimate interaction that may not fit the canonical circulative nonpropagative transmission.IMPORTANCEA specific mode of interaction between viruses and arthropod vectors has been extensively described in plant viruses in the three familiesLuteoviridae,Geminiviridae, andNanoviridae, but never in arboviruses of animals. This so-called circulative nonpropagative transmission contrasts with the classical biological transmission of animal arboviruses in that the corresponding viruses are thought to cross the vector cellular barriers, from the gut lumen to the hemolymph and to the salivary glands, without expressing any of their genes and without replicating. By monitoring the genetic composition of viral populations during the life cycle ofFaba bean necrotic stunt virus(FBNSV) (genusNanovirus), we demonstrate reproducible genetic changes during the transit of the virus within the body of the aphid vector. These changes do not fit the view that viruses simply traverse the bodies of their arthropod vectors and suggest more intimate interactions, calling into question the current understanding of circulative nonpropagative transmission.

scholarly journals A Single Rep Protein Initiates Replication of Multiple Genome Components of Faba Bean Necrotic Yellows Virus, a Single-Stranded DNA Virus of Plants

1999 ◽  
Vol 73 (12) ◽  
pp. 10173-10182 ◽  
Author(s):  
Tatiana Timchenko ◽  
Françoise de Kouchkovsky ◽  
Lina Katul ◽  
Chantal David ◽  
Heinrich Josef Vetten ◽  
...  
Keyword(s):  
Faba Bean ◽  
Dna Cleavage ◽  
Plant Viruses ◽  
Site Directed Mutagenesis ◽  
Nucleoside Triphosphate ◽  
Dna Virus ◽  
Single Stranded Dna ◽  
Rep Protein ◽  
Rep Proteins

ABSTRACT Faba bean necrotic yellows virus (FBNYV) belongs to the nanoviruses, plant viruses whose genome consists of multiple circular single-stranded DNA components. Eleven distinct DNAs, 5 of which encode different replication initiator (Rep) proteins, have been identified in two FBNYV isolates. Origin-specific DNA cleavage and nucleotidyl transfer activities were shown for Rep1 and Rep2 proteins in vitro, and their essential tyrosine residues that catalyze these reactions were identified by site-directed mutagenesis. In addition, we showed that Rep1 and Rep2 proteins hydrolyze ATP, and by changing the key lysine residue in the proteins’ nucleoside triphosphate binding sites, demonstrated that this ATPase activity is essential for multiplication of virus DNA in vivo. Each of the five FBNYV Rep proteins initiated replication of the DNA molecule by which it was encoded, but only Rep2 was able to initiate replication of all the six other genome components. Furthermore, of the fiverep components, only the Rep2-encoding DNA was always detected in 55 FBNYV samples from eight countries. These data provide experimental evidence for a master replication protein encoded by a multicomponent single-stranded DNA virus.

scholarly journals A Cross-Metabolomic Approach Shows that Wheat Interferes with Fluorescent Pseudomonas Physiology through Its Root Metabolites

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 84
Author(s):  
Laura Rieusset ◽  
Marjolaine Rey ◽  
Florence Gerin ◽  
Florence Wisniewski-Dyé ◽  
Claire Prigent-Combaret ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Host Plant ◽  
Soil Microorganisms ◽  
Wheat Root ◽  
Bioactive Metabolites ◽  
Root Extracts ◽  
Fluorescent Pseudomonas ◽  
Health And Development ◽  
The Impact ◽  
Metabolomic Approach

Roots contain a wide variety of secondary metabolites. Some of them are exudated in the rhizosphere, where they are able to attract and/or control a large diversity of microbial species. In return, the rhizomicrobiota can promote plant health and development. Some rhizobacteria belonging to the Pseudomonas genus are known to produce a wide diversity of secondary metabolites that can exert a biological activity on the host plant and on other soil microorganisms. Nevertheless, the impact of the host plant on the production of bioactive metabolites by Pseudomonas is still poorly understood. To characterize the impact of plants on the secondary metabolism of Pseudomonas, a cross-metabolomic approach has been developed. Five different fluorescent Pseudomonas strains were thus cultivated in the presence of a low concentration of wheat root extracts recovered from three wheat genotypes. Analysis of our metabolomic workflow revealed that the production of several Pseudomonas secondary metabolites was significantly modulated when bacteria were cultivated with root extracts, including metabolites involved in plant-beneficial properties.

scholarly journals First Report of Apricot vein clearing-associated virus (AVCaV) infecting Prunus domestica revealed by High-Throughput Sequencing in Morocco

Plant Disease ◽  
2020 ◽  
Author(s):  
Rachid Tahzima ◽  
Radouane Qessaoui ◽  
Yoika Foucart ◽  
Sebastian Massart ◽  
Kris De Jonghe
Keyword(s):  
Fruit Trees ◽  
Plant Viruses ◽  
Amino Acid Sequences ◽  
Stone Fruit ◽  
Replicase Gene ◽  
Prunus Domestica ◽  
Prunus Species ◽  
First Report ◽  
Vein Clearing ◽  
The Impact

Plum (Prunus domestica L., Rosaceae) trees, like many stone fruit trees, are known to be infected by numerous plant viruses, predominantly as consequence of their clonal mode of propagation and perennial cultivation (Jelkmann and Eastwell, 2011). Apricot vein clearing-associated virus (AVCaV) is a member of the genus Prunevirus in the family Betaflexiviridae. AVCaV was first reported in Italy infecting apricot (P. armeniaca L.) associated with foliar vein clearing symptoms (Elbeaino et al. 2014). It has also been detected in various Prunus species, like plum, Japanese plum (P. salicina L.), sour cherry (P. cerasus L.), and Japanese apricot (P. mume L.), apricot and peach (P. persica L.) sourced from Asian and European countries (Marais et al. 2015), as well as in the ornamental Myrobolan plum (P. cerasifera L.) in Australia (Kinoti et al. 2017). In 2018, during the vegetative season, a survey was carried out in two different apricot and plum orchards in the southern region of Agdez (Agadir, Morocco) where stone fruit trees are grown. Five branches with leaves were sampled from three apricot and three plum trees of unknown cultivars, all asymptomatic. Total RNA was extracted from 100 mg plant tissue (leaves and cambial scrapping) using RNeasy Plant Mini Kit (QIAGEN, Hilden, Germany) and separate samples (one per species) were used for library preparation (NEBNext Ultra RNA library kit; New England BioLabs, MA, USA), and sequencing (Illumina NextSeq v2, totRNA sequencing) at Admera Health (New Jersey, USA). All generated reads (6,756,881) from the plum sample were quality filtered and submitted to the VirusDetect pipeline (Zheng et al., 2017). The plum cDNA library, a total of 20 viral contigs (68-1928 bp) mapped to several AVCaV accessions in GenBank. A reference mapping (CLC Genomics Workbench 12, Qiagen, Denmark) was conducted against all four available AVCaV full genomes (KM507062-63, KY132099 and HG008921), revealing 100% coverage of the full sequence (8358 nt) with 97-98 % nucleotide (nt) identities (BLASTn). Analysis of the derived sequences allowed to identify the location of the four predicted ORFs i.e. (ORF1: 6066 nt/2,021 aa), (ORF2: 1383 nt/460 aa), (ORF3: 666 nt/221 aa) and (ORF4: 420 nt/139 aa), previously described for the AVCaV genome (Elbeaino et al. 2014). The amino acid sequences of the encoded proteins of AVCaV isolate from Morocco also shared 97-98% identities with the corresponding sequences of complete genome AVCaV isolates in GenBank. To confirm the detection of AVCaV in the three plum samples, specific RT-PCR primers (VC37657s: 5’-CCATAGCCACCCTTTTTCAA-3’ / VC28239a: 5’-GTCGTCAAGGGTCCAGTGAT-3’) (Elbeaino et al. 2014) were used and the expected 330 bp fragment from the replicase gene was amplified in all three samples and subsequently sequenced (MT980794-96). Sanger sequences were 100% identical to corresponding HTS derived sequence. This is the first report of AVCaV infecting plum in Africa. The incidence of AVCaV in Moroccan Prunus species is unknown. Plum trees from the surveyed orchards were also confirmed to be co-infected with little cherry virus 1 (LChV-1) using HTS. Further investigation is required to determine the impact of AVCaV on these asymptomatic plum trees and other stone fruits species.

scholarly journals First Detection of Faba bean necrotic yellow virus in Spain

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 707-707 ◽  
Author(s):  
M. Babin ◽  
V. Ortíz ◽  
S. Castro ◽  
J. Romero
Keyword(s):  
Faba Bean ◽  
Acyrthosiphon Pisum ◽  
Virus Disease ◽  
Epidemiological Data ◽  
Aphid Transmission ◽  
Enzyme Linked Immunosorbent Assay ◽  
Yellow Virus ◽  
Potential Threat ◽  
Bean Plants ◽  
Faba Beans

Faba bean necrotic yellow virus (FBNYV) was not detected during 1994 to 1996 field surveys of faba beans (Vicia faba L.) in Spain (1). In 1997, however, one sample with symptoms of necrosis, collected in Baleares, was tested using ELISA (enzyme-linked immunosorbent assay) and was positive for both Tomato spotted wilt virus (TSWV) and FBNYV. FBNYV is a single-strand DNA virus that is transmitted by aphids and is the main virus disease of broad bean in North Africa and West Asia (2). During 1997 to 1999, faba bean plants with symptoms of necrosis, yellowing, small leaves, and stunting were collected from several fields in the Murcia Region (Spain) and were analyzed using ELISA. To detect FBNYV, we used monoclonal 2E9 supplied by H. J. Vetten (Institute of Plant Virology, Microbiology and Biosafety, BBA, Braunschweig, Germany). Of 700 samples analyzed, 34 were positive for FBNYV. Of the 34 positive samples, 12 tested positive, using commercial antiserum from Loewe, Inc. (Munich) for mixed infections with TSWV. FBNYV was transmitted to healthy faba bean plants by aphids (Acyrthosiphon pisum) in greenhouse experiments and was confirmed by ELISA. Preliminary epidemiological data showed a gradual increase in the number of plants infected with time in the same field. Aphid transmission of FBNYV to faba beans has established the disease in Spain and is a potential threat to other leguminous crops. This is the first report of a nanovirus in Europe. References: (1) J. Fresno et al. Plant Dis. 81:112, 1997. (2) L. Katul et al. Ann. Appl. Biol. 123:629, 1993.

scholarly journals Drop when the stakes are high: adaptive, flexible use of dropping behaviour by aphids

Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley
Keyword(s):  
Host Plant ◽  
Acyrthosiphon Pisum ◽  
Adalia Bipunctata ◽  
Macrosiphum Euphorbiae ◽  
Herbivorous Insects ◽  
Chrysoperla Carnea ◽  
Pea Aphids ◽  
Potato Aphids ◽  
Antipredator Defence

Abstract For herbivorous insects, dropping from the host plant is a commonly-observed antipredator defence. The use of dropping compared to other behaviours and its timing in relation to contact with a predator was explored in both pea aphids (Acyrthosiphon pisum) and potato aphids (Macrosiphum euphorbiae). Pea aphids dropped more frequently in response to ladybird adults (Adalia bipunctata) than lacewing larvae (Chrysoperla carnea). Potato aphids mainly walked away or backed-up in response to both predator types; but they dropped more frequently relative to other non-walking defences when faced with ladybird adults. Contact with a predator was an important influencer of dropping for both species, and most drops occurred from adjacent to the predator. Dropping appears to be a defence adaptively deployed only when the risk of imminent predation is high; factors that increase dropping likelihood include presence of faster-foraging predators such as adult ladybirds, predator proximity, and contact between aphid and predator.

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