Abstract
Endornaviruses include viruses that infect fungi, oomycetes, and plants. The genome of plant endornaviruses consists of linear ssRNA ranging in size from approximately 13-18 kb and lacking capsid protein and cell-to-cell movement capability. Although, plant endornaviruses have not been shown to cause detectable changes in the plant phenotype, they have been associated with alterations of the host physiology. Except for the association of cytoplasmic vesicles with infections by Vicia faba endornavirus, effects on the plant cell ultrastructure caused by endornaviruses have not been reported. Bell pepper endornavirus (BPEV) has been identified in several pepper (Capsicum spp.) species. We conducted ultrastructural analyses of cells from two near-isogenic lines of the bell pepper (C. annuum) cv. Marengo, one infected with BPEV and the other BPEV-free, and found cellular alterations associated with BPEV-infections. Some cells of plants infected with BPEV exhibited alterations of organelles and other cell components. Affected cells were located mainly in the mesophyll and phloem tissues. Altered organelles included mitochondrion, chloroplast, and nucleus. The mitochondria from BPEV-infected plants exhibited low number of cristae and electron-lucent regions. Chloroplasts contained plastoglobules and small vesicles in the surrounding cytoplasm. Translucent regions in thylakoids were observed, as well as hypertrophy of the chloroplast structure. Many membranous vesicles were observed in the stroma along the envelope. The nuclei revealed a dilation of the nuclear envelope with vesicles and perinuclear areas. The organelle changes were accompanied by membranous structure rearrangements, such as paramural bodies and multivesicular bodies. These alterations were not observed in cells from plants of the BPEV-free line. Overall, the observed ultrastructural cell alterations associated with BPEV are similar to those caused by plant viruses and viroids and suggest some degree of parasitic interaction between BPEV and the plant host.
Introduction
Peppers (Capsicum species in the family Solanaceae) are native plants from the Americas and are cultivated worldwide as food crops (; ). Although there are five domesticated Capsicum species (C. annuum, C. baccatum, C. chinense, C. frutescens, and C. pubescens), C. annuum is the most commonly cultivated (; ; ). Several C. annuum horticultural types have been identified, including bell, cayenne, jalapeño, ancho, serrano, poblano, and others ().
Based on host symptom expression, plant viruses can be divided into two categories: acute and persistent (). Acute viruses are transmitted horizontally and, in some cases, vertically. Their genome encodes for a cell-to-cell movement protein (MP), which in combination with other proteins gives them the ability to spread from the point of initial infection (). In contrast, persistent viruses do not cause morphological symptoms; they lack MP and are transmitted only vertically via gametes (; ). Persistent plant viruses include members of the families Amalgaviridae, Chrysoviridae, Endornaviridae, Nardaviridae, Partitiviridae, and Totiviridae (; ; ; ). Persistent viruses have been reported to infect economically important crops such as alfalfa, avocado, corn, sugar beet, common bean, rice, pepper, melon, radish, and tomato (; ; ; ; Villanueva et al., 2012; ; ; ). However, due to the lack of symptom induction and the lack of transmission by conventional methods, persistent viruses have been poorly studied. Interactions of persistent viruses with the host, acute viruses, and other biotic and abiotic agents have not been investigated.
Viruses in the family Endornaviridae infect fungi, oomycetes, and plants (; ). The genome of plant endornaviruses consist of linear positive sense ssRNA ranging in size from approximately 13–18 k and lacking capsid protein (CP) and MP (; ; ). Indirect evidence suggests they are present in all tissues of the infected plant (). Like other persistent plant viruses, they have not been shown to cause visible phenotypic changes in the host (; ; ). Nevertheless, plant endornaviruses have been associated with alterations of the host physiology such as seed germination, cytoplasmic male sterility, and chlorophyll content (; ; ).
Bell pepper endornavirus (BPEV) has been identified in many C. annum cultivars but particularly in the bell pepper horticultural type (Valverde et al., 1990; ; ). Moreover, a closely related virus, Capsicum frutescens endornaviurus 1 (CFEV 1), has been reported infecting several domesticated Capsicum species (). Safari and Roossinck showed that BPEV occur only in C. annuum. In contrast, CFEV 1 was detected in C. frutescens, C. chinense, and C. baccatum. These results suggest that endornaviruses of Capsicum are not species-specific.
In a comparative study using near-isogenic lines (NILs) of bell pepper cv. Marengo, one BPEV-infected and the other BPEV-free, determined that BPEV was not associated with changes in the host phenotype. However, the plant height, number of fruits, and total fruit weight was higher in plants of the BPEV-free line than in plants of the BPEV-infected line. However, in most experiments, the differences were not statistically significant. concluded that BPEV appears to have a weak parasitic relationship with the host.
Except for the association of cytoplasmic vesicles in Vicia faba with infections by Vicia faba endornavirus (VfEV) (), studies on the effects on the plant cell ultrastructure by endornaviruses have not been reported. One factor contributing to the lack of studies is that plant endornaviruses are not transmitted by conventional virus-inoculation methods; therefore, results from comparative studies using different plant genotypes are not reliable. The availability of BPEV-infected and BPEV-free near-isogenic lines provided us with material to conduct a comparative study to determine if ultrastructural changes in bell pepper are associated with BPEV infections. In this investigation, we conducted an ultrastructural analysis of leaf tissues of two near-isogenic lines of the bell pepper cultivar Marengo, one infected with BPEV and the other BPEV-free, and report the association of ultrastructural cytopathology with BPEV infections.
Materials and Methods
Plant Material
Seeds from two NILs of C. annuum cv. Marengo, one infected with BPEV and the other BPEV-free, developed in previous investigations () were planted and grown in a phytotron growth chamber at 20°C and 16 h light with an intensity of 400 μmol m-2 s-1 PAR (photosynthetically active radiation). The plant phenotype of both lines was visually examined (daily) throughout their life cycle. The presence or absence of BPEV in experimental plants was tested by analysis of viral replicative form dsRNA by gel electrophoresis and reverse transcription PCR (RT-PCR) as described in previous investigations (; ). Furthermore, plants were tested for the presence of pepper mild mottle virus by RT-PCR (). Total RNA extracted from healthy tobacco (Nicotiana tabaccum) plants with the Spectrum Plant Total RNA Kit (Sigma-Aldrich, St. Louis, MO) was used as negative control in RT-PCR reactions.
Tissue Preparation for Light Microscopy and Transmission Electron Microscopy (TEM) Examinations
Leaves from two-month-old plants of both NILs at similar developmental stage were selected for transmission electron microscope examinations. Thirty-five sections (2 mm2) were excised from each NIL and fixed as reported previously (, ). Briefly, tissues were initially fixed as described by and in 2% (w/v) osmium tetroxide solution in 0.05 M cacodylate buffer for 2 h at 4°C. Samples were dehydrated in ethanol series and embedded in Epoxy resin (Epon812, Sigma) with polymerization for 24 h at 60°C. For the examination of the anatomy, glass slides with macro-sections were stained with crystal violet solution () and examined with a AX70 PROVIS light microscope with an Olympus UP90 High Definition camera (Olympus, Warsaw, Poland) using Olympus Cell Sense Standard Software (Olympus, Center Valley, PA, United States, version 1.18). Ultrathin sections (70–80 nm) were obtained using an UCT ultramicrotome (Leica Microsystems) and collected on formvar-coated copper grids. Grids were stained with 1.2% uranyl acetate and 2.5% lead citrate. Analyses of ultrathin sections from leaves of both NILs were performed using a transmission electron microscope (268D Morgagni TEM (FEI) at 80 kV) as previously described (, ). Images were captured with a Morada digital camera (Olympus SIS). All foliar sections were examined without knowledge of whether they were BPEV-infected or BPEV-free.
Results
Gel electrophoresis and RT-PCR testing of plants of the two lines used for the ultrastructural analysis confirmed the presence of BPEV in BPEV-infected plants and absence of BPEV in BPEV-free plants (Supplementary Figures S1A,B). Moreover, pepper mild mottle virus was not detected in any of the experimental plants.
Morphology and Anatomy of Near-Isogenic Lines (NILs)
As reported in previous investigations (; ), we did not observe phenotypical differences between the BPEV-infected and the BPEV-free bell pepper NILs (Figures 1A,B). Moreover, light microscopy examinations of cross sections of foliar tissues from both lines did not show visible differences on their anatomy (Figures 1C,D).
FIGURE 1
Cellular Ultrastructural Changes Associated With Bell Pepper Endornavirus Infection
Electron microscopy examinations of foliar tissues of the two lines did not yield any evidence of virus-like particles or viral inclusion bodies.
Ultrastructural alterations of cell organelles and other components were observed in bell pepper tissues infected with BPEV. Some or all of these alterations were consistently observed in some cells of all 35 analyzed leaf sections. The altered cells were located mainly in the mesophyll and phloem tissues.
One type of alteration consisted of necrosis of palisade mesophyll cells, which contained electron-dense cytoplasm (Figure 2A). Necrosis of some phloem elements was also observed (Figure 2B). The necrosis of the phloem cells was associated with collapsing of the sieve tubes and cell wall invaginations (Figure 2C). The altered ultrastructure of the sieve tubes was associated with abnormal companion cells. When compared with similar cells of the BPEV-free line (Figure 3), cells of the BPEV-infected line showed a decreased number of mitochondria and contained some mitochondria without crista (Figure 2D). In addition, these cells exhibited electron-dense regions along the cell wall, whereas, sieve tubes were filled with callose-like material (Figure 2D). Further analyses of phloem tissue cells revealed alterations of the cell wall. The spectrum of cell wall changes ranged from loss of cell wall structure, often near plasmodesmata (Figure 4A) to irregular cell wall invaginations associated with membranous paramural bodies (Figures 4B–E). Paramural bodies were observed associated with the cell wall of some phloem parenchyma, epidermis, and mesophyll cells. These paramular bodies were often located near the tonoplast of vacuoles, suggesting movement from the apoplast to the vacuoles. Membrane bound structures associated with the symplast region, such as multivesicular bodies were commonly observed in some cells from tissues of the BPEV-infected line. These multivesicular bodies varied in shape and occurred in the cytoplasm and vacuoles of mesophyll, phloem, and sometimes xylem parenchyma cells (Figures 5A–D). Numerous granular structures were frequently present inside the multivesicular bodies.
FIGURE 2
FIGURE 3
FIGURE 4
FIGURE 5
Further analysis of cells from the BPEV-infected line revealed ultrastructural changes in some cell organelles. The mitochondria exhibited a variety of structural alterations, which included a decrease number of crista and electron-lucent regions (Figures 6A,B). Mitochondria with electron-lucent areas formed an expanded exosome like vesicles (Figures 6C,D). None of these changes were observed in mitochondria of cells of the BPEV-free line (Figure 6E).
FIGURE 6
When compared with chloroplast from cells of the BPEV-free line (Figure 7A), alterations of the chloroplast structure was observed in cells of the BPEV-infected line. The structure of the chloroplast thylakoids was altered (Figure 7B). Changes of the normal chloroplast shape and presence of small vesicles inside stroma were observed in some BPEV-infected cells (Figure 7C). Plastoglobules and small vesicles were often observed outside the chloroplast envelope (Figures 7C,D). Hypertrophy of the chloroplast structure included translucent regions in thylakoids and the presence of numerous membranous vesicles in stroma along envelope (Figures 7E,F).
FIGURE 7
Some phloem parenchyma cells from the BPEV-infected line contained nuclei with dilation of the nuclear envelope and vesicles and perinuclear areas (Figure 8A). Whereas, in the mesophyll cells, lobed nucleus with translucent regions containing small vesicles were often observed (Figures 8B,C), including strong chromatin condensation (Figure 8D). None of the changes in cell organelles and other cell components described above were observed in cells of BPEV-free line (Figure 8E).
FIGURE 8
The alterations described above were not observed in all cells of the BPEV-infected line. Many cells of the BPEV-infected line contained unaltered organelles and other cell components which were undistinguishable from the organelles and cell components of the BPEV-free line.
Discussion
Previous studies have reported that plants infected with endornaviruses are symptomless (; ; ). The genomes of these viruses do not code for a CP, and therefore, it is not surprising that virions have not been reported in endornavirus-infected cells (Valverde et al., 1990; Zabalgogeazcoa and Gildow, 1992; ). Limited studies on the cellular location of the RNA of plant endornaviruses suggest that they are concentrated in the cytoplasm (; Valverde et al., 1990; ; ). The replicative form of the genomic RNA (dsRNA) of VfEV-infected V. faba has been found to be associated with cytoplasmic vesicles and viral dsRNA isolated from purified vescicles (). As mentioned earlier in this paper, at the present time, other than the vesicles in VfEV-infected cells, no cytopathic effects have been reported as associated with endornaviruses, and there is no information on the effect of endornaviruses to cell organelles or other cell components.
The formation of cytoplasmic vesicles is one of the most common cellular responses to infection of plants by viruses (). In this investigation, we observed cytoplasmic vesicles and multivesicular bodies in BPEV-infected cells which were similar to those reported in plants infected with acute viruses. In plant cells, single-stranded positive-sense RNA viruses generate cytoplasmic membranous vesicles, where viral replication takes place (Wei and Wang, 2008). These vesicles contain viral ssRNA, replicative dsRNA, and proteins involved in virus replication (; ; ). Vesicles can be developed from membranes of various cell organelles such as chloroplasts, mitochondria, peroxisomes, endoplasmic reticulum, or tonoplast (; ; ; ). Multivesicular bodies have been reported in cells infected with tomato bunchy top virus (). Cytoplasmic vesicles apparently formed by invaginations of the plasma membrane have been reported in tomato plants infected with potato spindle tuber viroid. Membrane-bound vesicles (50-90 nm in diameter) have been observed in fungi infected with hypoviruses (; ). Moreover, the presence of a large number multivesicular bodies has been associated with viral genome replication (; ). Multivesicular bodies have also been associated with cell wall-associated defense response in barley leaves infected with the pathogen that causes powdery mildew (, ). Cytoplasmic vesicles and multivesicular bodies generated in BPEV-infected cells suggest involvement of these structures in the virus replication as reported for brome mosaic virus (). Paramural bodies observed in cells infected with BPEV are similar to paramular bodies observed in the potato virus Y (PVY)-resistant potato cultivar Sárpo Mira when infected with PVY (). Paramural bodies and membrane alterations have also been reported in cells infected with potato spindle tuber viroid ().
Plant viruses have been shown to target photosynthesis and negatively affect the chloroplast function, including host chlorophyll content (Zhao et al., 2016). Morphological changes of the chloroplast have been reported to be associated with plant virus or viroid infections (; ). It has been shown that the chloroplasts of potato spindle tuber viroid-infected cells exhibit reduced grana and loosely arranged thylakoids (). reported that barley stripe mosaic virus caused alterations of the wheat chloroplast membranes, characterized by the clustering of outer membrane-invaginated spherules in inner membrane-derived packets. They also observed diverse morphologies of cytoplasmic invaginations with spherules at the periphery and different sized openings connecting the cytoplasmic invaginations with the cytoplasm (). We observed similar changes of the chloroplast and cytoplasm in cells of the BPEV-infected line. In a comparative study of endornavirus-infected and endornavirus-free common bean (Phaseolus vulgaris), reported statistically significantly lower chlorophyll content of the endornavirus-infected line. Although in the case of bell pepper and BPEV, did not find statistically significant differences on the amount of chlorophyll content between infected and healthy lines.
The mitochondria in BPEV-infected cells exhibited a variety of structural alterations which included electron-lucent areas and expanded exosome like vesicles. In turnip, infections by turnip mosaic virus causes vesicularization of the outer mitochondrial membranes (; ; ). Electron microscopic observations of thin sections of cells from tissues infected with cucumber green mottle mosaic virus revealed the formation of small vesicles in the mitochondria (). reported that melon necrotic spot virus replication occurs in association with altered mitochondria. Cytoplasmic vesicles that develop from modified mitochondria have been shown to be associated with infections by tombusviruses (). reported smaller and fewer mitochondria in the fungus Chalara elegans infected with a mitovirus. Mitoviruses are small RNA viruses that infect plants and fungi and replicate in the mitochondria ().
Many of the cellular alterations reported in this investigation resemble effects caused by biotic and abiotic stresses in plants. Although infected bell pepper plants containing the described cell alterations did not appear diseased, these alterations should negatively affect the normal plant physiology. In spite of the presence of clusters of necrotic cells, we did not observe tissue necrosis. It is possible that the number of necrotic cells was below the threshold to cause visible necrosis. The observed cellular alterations may explain the lower seed germination, plant height, number of fruits, and total fruit weight of BPEV-infected plants than plants of the BPEV-free line reported by .
While conducting investigations on the coevolution of Capsicum endornaviruses and the host, generated data to support the idea that the ancestor of CFEV 1, may have evolved as BPEV in C. annuum. In the United States, BPEV has been detected in all tested bell pepper (C. annuum) cultivars (; ). This suggests that bell pepper breeders have selected only BPEV-infected lines to develop commercial cultivars and therefore BPEV may provide an unknown beneficial effect to the plant. Similarly, most melon cultivars tested for Cucumis melo endornavirus have been found infected (). Nevertheless, it is possible that the beneficial effects may be effective only under certain environmental conditions. Common bean (Phaseolus vulgaris) cultivars of Mesoamerican origin have been reported to be double-infected by two endornaviruses, Phaseolus vulgaris endornavirus 1 (PvEV1) and Phaseolus vulgaris endornavirus 2 (PvEV2), whereas most genotypes of Andean origin were endornavirus-free (; ). This differential occurrence according to the crop origin suggests that like BPEV, PvEV1 and PvEV2 may provide unidentified beneficial effects to common bean grown in Mesoamerica but not to that grown in the Andean region. A differential infection pattern has also been reported for Oryza sativa endornavirus in Indica and Japonica rice ().
Only limited studies on the association of endornaviruses with changes in the host biology have been conducted (; ; ). Endornaviruses of common bean and bell pepper have been associated with statistically significant variations in seed germination rates (; ). There is evidence that suggests that endornaviruses activate the plant host gene silencing system and therefore play an active role in the physiology of the infected plant (; ). The lack of symptom induction suggests that endornaviruses are able to evade the silencing mechanism of the host, possibly by using a unique suppressor of silencing or other unknown mechanism. has suggested that the host regulates endornavirus copy number and propagation and that unknown host factors, which could be proteins involved in RNA silencing, control virus replication. Nevertheless, in the case of bell pepper, alterations of the ultrastructure of some host cells were associated with BPEV infections without causing visible external symptoms. Although not yet experimentally confirmed, it is assumed that endornaviruses are present in all cells of an infected plant; we do not have an explanation for the presence of cells with altered and non-altered organelles and other cell components in BPEV-infected plants. It is possible that alterations occur only in cells lacking host control on endornavirus replication.
Statements
Data availability statement
All datasets generated for this study are included in the article/Supplementary Material.
Author contributions
KO-K and EK conducted the light and electron microscopy experiments, data analyses, and participated in writing the manuscript. CE conducted dsRNA extractions and RT-PCR testing. RV developed bell pepper near-isogenic lines and participated in writing the manuscript.
Funding
This investigation was partly financed by the Statutory research fund of the Institute of Biology, Department of Botany (Warsaw University of Life Sciences-SGGW). Partial support for this investigation was also provided by the National Institute of Food and Agriculture, USDA, United States.
Acknowledgments
We would like to express sincere thanks to EZ for her excellent ultramicrotome work and to M. J. Roossinck, Penn State University, United States for kindly providing the original endornavirus-free line of Marengo bell used to develop the near-isogenic lines used in this study. We also thank A. Hebert, Middleton Library, Louisiana State University, for editing the manuscript.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Supplementary material
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpls.2020.00491/full#supplementary-material
References
1
AkinyemiI. A.WangF.ChangZ. X.WuK. (2018). Genome characterization of the newly identified maize-associated totivirus Anhui.Arch. Virol.163:2929. 10.1007/s00705-018-3929-0
2
AnQ.HückelhovenR.KogelK. H.van BelA. J. E. (2006a). Multivesicular bodies participate in a cell wall-associated defence response in barley leaves attacked by the pathogenic powdery mildew fungus.Cell. Microbiol.81009–1019. 10.1111/j.1462-5822.2006.00683.x
3
AnQ.EhlersK.KogelK. H.van BelA. J. E.HückelhovenR. (2006b). Multivesicular compartments proliferate in susceptible and resistant MLA12-barley leaves in response to infection by the biotrophic powdery mildew fungus.New Phytol.172563–576. 10.1111/j.1469-8137.2006.01844.x
4
BamunusingheD.SeoJ. K.RaoA. L. (2011). Subcellular localization and rearrangement of endoplasmic reticulum by Brome mosaic virus capsid protein.J. Virol.852953–2963. 10.1128/JVI.02020-10
5
BlakeJ. A.KitW.LeeK. W.MorrisT. J.EltonT. E. (2007). Effects of turnip crinkle virus infection on the structure and function of mitochondria and expression of stress proteins in turnips.Physiol. Plant.129698–706. 10.1111/j.1399-3054.2006.00852.x
6
BoccardoG.LisaV.LuisoniE.MilneR. G. (1987). Cryptic plant viruses.Adv. Virus Res.32171–214. 10.1016/s0065-3527(08)60477-7
7
BoslandP. W.BaileyA. L.Iglesias-OlivasJ. (1996). Capsicum Pepper Varieties and Classification.New Mexico: State University Cooperative Extension Service.
8
CabanillasD. G.JiangJ.MovahedN.GermainH.YamajiY.ZhengH.et al (2018). Turnip mosaic virus uses the SNARE protein VTI11 in an unconventional route for replication vesicle trafficking.Plant Cell302594–2615. 10.1105/tpc.18.00281
9
CottonS.GrangeonR.ThiviergeK.MathieuI.IdeC.WeiT.et al (2009). Turnip mosaic virus RNA replication complex vesicles are mobile, align with microfilaments, and are each derived from a single viral genome.J. Virol.8310460–10471. 10.1128/jvi.00819-09
10
DeWittD.BoslandP. D. (1996). Peppers of the World: An Identification Guide.Berkeley, CA: Ten Speed Press.
11
Di FrancoA.RussoM.MartelliG. P. (1984). Ultrastructure and origin of cytoplasmic multivesicular bodies induced by carnation Italian ringspot virus.J. Gen. Virol.651233–1237. 10.1099/0022-1317-65-7-1233
12
DoljaV. V.KooninE. V. (2018). Metagenomics reshapes the concepts of RNA virus evolution by revealing extensive horizontal virus transfer.Virus Res.24436–52. 10.1016/j.virusres.2017.10.020
13
DulieuP.PeninP.DulieuH.GautheronD. C. (1988). Purification of virus-like particles from Vicia faba and detection by ELISA in crude leaf extracts.Plant Sci.569–14. 10.1016/0168-9452(88)90178-1
14
EscalanteC.ValverdeR. A. (2019). Morphological and physiological characteristics of endornavirus-infected and endornavirus-free near-isogenic lines of bell pepper (Capsicum annuum).Sci. Hort.250104–112.
15
FranckiR. I. B. (1987). “Responses of plant cells to virus infection with special reference to the sites of RNA replication,” in Positive Strand RNA Viruses, edsBrintonM. A.RueckertR. R. (New York, NY: Alan R Liss Inc), 423.
16
FukuharaT. (1999). Double-stranded RNA in rice.J. Plant Pathol.112131–138.
17
FukuharaT. (2019). Endornaviruses: persistent dsRNA viruses with symbiotic properties in diverse eukaryotes.Virus Genes55165–173. 10.1007/s11262-019-01635-5
18
FukuharaT.MoriyamaH.PakJ. Y.HyakutakeH.NitaT. (1993). Enigmatic double-stranded RNA in Japonica rice.Plant Mol. Biol.19931121–1130. 10.1007/bf00023608
19
Gómez-AixC.García-GarcíaM.ArandaM. A.Sánchez-PinaM. A. (2015). Melon necrotic spot virus replication occurs in association with altered mitochondria.Mol. Plant Microbe Interat.28387–397. 10.1094/mpmi-09-14-0274-r
20
GrillL. K.GargerS. J. (1981). Identification and characterization of double-stranded RNA associated with cytoplasmic male sterility in Vicia faba.Proc. Natl. Acad. Sci. U.S.A.787043–7046. 10.1073/pnas.78.11.7043
21
HariV. (1980). Ultrastructure of potato spindle tuber viroid-infected tomato leaf tissue.Phytopathology70385–387.
22
HattaT.FranckiR. I. B. (1980). Cytopathic structures associated with tonoplasts of plant cells Infected with cucumber mosaic and tomato aspermy viruses.J. Gen. Virol.53343–346. 10.1099/0022-1317-53-2-343
23
HattaT.UshiyamaR. (1973). Mitochondrial vesiculation associated with cucumber green mottle mosaic virus-infected plants.J. Gen. Virol.2I9–17. 10.1099/0022-1317-21-1-9
24
JarretR. L.GillaspieA. G.BarkleyN. A.PinnowD. L. (2008). The occurrence and control of pepper mild mottle virus (PMMoV) in the USDA/ARS Capsicum germplasm collection.Seed Technol.3026–36.
25
KarnovskyM. J. (1965). A formaldehyde-glutaraldehyde fixative of high osmolality for use in electron-microscopy.J. Cell Biol.27137–138.
26
KhalifaM. E.PearsonM. N. (2014). Characterisation of a novel hypovirus from Sclerotinia sclerotiorum potentially representing a new genus within the Hypoviridae.Virology464-465441–449. 10.1016/j.virol.2014.07.005
27
KhankhumS.EscalanteC.Rodrigues de SoutoE.ValverdeR. A. (2017). Extraction and electrophoretic analysis of large dsRNAs from desiccated plant tissues infected with plant viruses and biotrophic fungi.Eur. J. Plant. Pathol.147431–441. 10.1007/s10658-016-1014-7
28
KhankhumS.ValverdeR. A. (2018). Physiological traits of endornavirus-infected and endornavirus-free common bean (Phaseolus vulgaris) cv Black Turtle Soup.Arch. Virol.1631051–1056. 10.1007/s00705-018-3702-4
29
KhankhumS.ValverdeR. A.Pastor-CorralesM.OsornoJ. M.SabanadzovicS. (2015). Two endornaviruses show differential infection patterns between gene pools of Phaseolus vulgaris.Arch.Virol.1601131–1137. 10.1007/s00705-015-2335-0
30
LalibertéJ. F.SanfaçonH. (2010). Cellular remodeling during plant virus infection.Annu. Rev. Phytopathol.4869–91. 10.1146/annurev-phyto-073009-114239
31
LalibertéJ. F.ZhengH. (2014). Viral manipulation of plant host membranes.Annu. Rev. Virol.1237–259. 10.1146/annurev-virology-031413-085532
32
LefebvreA.ScallaR.PfeifferP. (1990). The double-stranded RNA associated with the ‘447’ cytoplasmic male sterility in Vicia faba is packaged together with its replicase in cytoplasmic membranous vesicles.Plant Mol. Biol.14477–490. 10.1007/bf00027494
33
LiL.LiuJ.XuA.WangT.ChenJ.ZhuX. (2013). Molecular characterization of a trisegmented chrysovirus isolated from the radish Raphanus sativus.Virus Res.176169–178. 10.1016/j.virusres.2013.06.004
34
LinN.-S.LangenbergW. G. (1984). Chronology of appearance of barley stripe mosaic virus protein in infected wheat cells.J. Ultrastruct. Res.89309–323. 10.1016/s0022-5320(84)80047-7
35
LiuW.XinM.CaoM.QinM.LiuH.ZhaoS.et al (2018). Identification, characterization and full-length sequence analysis of a novel endornavirus in common sunflower (Helianthus annuus).J. Integra. Agric.1760345–60347.
36
MartelliG. P.Di FrancoA.RussoM. (1984). The origin of multivesicular bodies in tomato bushy stunt virus-Infected Gomphrena globosa plants.J. Ultrastruct. Res.88275–281. 10.1016/s0022-5320(84)90125-4
37
NewhouseJ. R.MacDonaldW. L.HochH. C. (1990). Virus-like particles in hyphae and conidia of European hypovirulent (dsRNA-containing) strains of Crypho-nectria parasitica.Can. J. Bot.6890–101. 10.1139/b90-013
38
NibertM. L.VongM.KarenK.FugateK. K.DebatH. J. (2018). Evidence for contemporary plant mitoviruses.Virology51814–24. 10.1016/j.virol.2018.02.005
39
OkadaR.KiyotaE.SabanadzovicS.MoriyamaH.FukuharaT.SahaP.et al (2011). Bell pepper endornavirus: molecular and biological properties and occurrence in the genus Capsicum.J. Gen. Virol.922664–2673.
40
OkadaR.YongC. K.ValverdeR. A.SabanadzovicS.AokiN.HotateS.et al (2013). Molecular characterization of two evolutionarily distinct endornaviruses co-infecting common bean (Phaseolus vulgaris).J. Gen. Virol.94220–229. 10.1099/vir.0.044487-0
41
OtulakK.ChoudaM.BujarskiJ.GarbaczewskaG. (2015). The evidence of Tobacco rattle virus impact on host plant organelles ultrastructure.Micron707–20. 10.1016/j.micron.2010.11
42
OtulakK.GarbaczewskaG. (2010). Ultrastructural events during hypersensitive response of potato cv. Rywal infected with necrotic strains of potato virus Y.Acta Physiol. Plant.32635–644.
43
OtulakK.GarbaczewskaG. (2013). The participation of plant cell organelles in compatible and incompatible Potato virus Y-tobacco and-potato plant interaction.Acta Physiol. Plant.3685–99. 10.1007/s11738-013-1389-4
44
Otulak-KoziełK.KoziełE.LockhartB. E. L. (2018). Plant cell wall dynamics in compatible and incompatible potato response to infection caused by potato virus Y (PVYNTN).Int. J. Mol. Sci.19:862. 10.3390/ijms19030862
45
Otulak-KoziełK.KoziełE.ValverdeR. A. (2019). The respiratory burst oxidase homolog D (RbohD) cell and tissue distribution in potato–potato virus Y (PVYNTN) hypersensitive and susceptible reactions.Int. J. Mol. Sci.20:2741. 10.3390/ijms20112741
46
ParkY.ChenX.PunjaZ. K. (2006). Molecular and biological characterization of a mitovirus in Chalara elegans (Thielaviopsis basicola).Phytopathology96468–479. 10.1094/phyto-96-0468
47
PfeifferP. (1998). Nucleotide sequence, genetic organization and expression strategy of the double-stranded RNA associated with the ‘447’ cytoplasmic male sterility in Vicia faba.J. Gen. Virol.792349–2358. 10.1099/0022-1317-79-10-2349
48
PickersgillB. (1997). Genetic resources and breeding of Capsicum spp.Euphytica96129–133.
49
RojasM. R.MalianoM. R.de SouzaJ. O.Vasquez-MayorgaM.de MacedoM. A.HamB.-K.et al (2016). “Cell-to-cell movement of plant viruses: a diversity of mechanisms and strategies,” in Current Research Topics in Plant Virology, edsWangA.ZhouX. (Cham: Springer), 10.1007/978-3-319-32919-2_5
50
RoossinckM. J. (2010). Lifestyles of plant viruses.Philos. Trans. R. Soc. Lond. B Biol. Sci.3651899–1905. 10.1098/rstb.2010.0057
51
RoossinckM. J.SabanadzovicS.Ryo OkadaR.ValverdeR. A. (2011). The remarkable evolutionary history of endornaviruses.J. Gen. Virol.922674–2678. 10.1099/vir.0.034702-0
52
SabanadzovicS.WintermantelW. M.ValverdeR. A.McCreightJ. D.Aboughanem-SabanadzovicN. (2016). Cucumis melo endornavirus: genome organization, host range and co-divergence with the host.Virus Res.21449–58. 10.1016/j.virusres.2016.01.001
53
SafariM.RoossinckM. J. (2018). Coevolution of a persistent plant virus and its pepper hosts.Mol. Plant Microb. Interact.31766–776. 10.1094/mpmi-12-17-0312-r
54
SelaN.LuriaN.DombrovskyA. (2012). Genome assembly of bell pepper endornavirus from small RNA.J. Virol.86:7721. 10.1128/jvi.00983-12
55
SmithP. G.VillalonB.VillaP. L. (1987). Horticultural classification of peppers grown in the United States.HortScience2211–13.
56
TakahashiH.FukuharaT.KitazawaH.KormelinkR. (2019). Virus Latency and the impact on plants.Front. Microbiol.10:2764. 10.3389/fmicb.2019.02764
57
UrayamaS.MoriyamaH.AokiN.NakazawaY.OkadaR.KiyotaE.et al (2010). Knock-down of OsDCL2 in rice negatively affects maintenance of the endogenous dsRNA virus, Oryza sativa endornavirus.Plant Cell Physiol.5158–67. 10.1093/pcp/pcp167
58
ValverdeR. A.KhalifaM. E.OkadaR.FukuharaT.SabanadzovicS. (2019). ICTV Virus taxonomy profile: Endornaviridae.J. Gen. Virol.1001204–1205. 10.1099/jgv.0.001277
59
ValverdeR. A.NamethS.AbdallaO.Al-MusaO.DesjardinsP. R.DoddsJ. A. (1990). Indigenous double-stranded RNA from pepper (Capsicum annum).Plant Sci.67195–201. 10.1016/0168-9452(90)90243-h
60
VillanuevaF.SabanadzovicS.ValverdeR. A.Navas-CastilloJ. (2012). Complete genome sequence of a double-stranded RNA virus from avocado.J. Virol.861282–1283. 10.1128/jvi.06572-11
61
WeiT.WangA. (2008). Biogenesis of cytoplasmic membranous vesicles for plant potyvirus replication occurs at the endoplasmic reticulum exit sites in a COPI- and COPII-dependent manner.J. Virol.8212252–12264. 10.1128/jvi.01329-08
62
ZabalgogeazcoaI. A.GildowF. E. (1992). Double-stranded ribonucleic acid in ‘Barsoy’ Barley.Plant Sci.83187–194. 10.1016/0168-9452(92)90078-z
63
ZhaoJ.ZhangX.HongY.LiuY. (2016). Chloroplast in plant–virus interaction.Front. Microbiol.7:1565. 10.3389/fmicb.2019.01565
Summary
Keywords
plant virus, Endornaviridae, electron microscopy, symptomless plants, plant organelle alterations, near isogenic lines, persistent virus
Citation
Otulak-Kozieł K, Kozieł E, Escalante C and Valverde RA (2020) Ultrastructural Analysis of Cells From Bell Pepper (Capsicum annuum) Infected With Bell Pepper Endornavirus. Front. Plant Sci. 11:491. doi: 10.3389/fpls.2020.00491
Received
31 January 2020
Accepted
01 April 2020
Published
28 April 2020
Volume
11 - 2020
Edited by
Miguel A. Martín-Acebes, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Spain
Reviewed by
Marilyn Roossinck, Pennsylvania State University (PSU), United States; Won Kyong Cho, Seoul National University, South Korea
Updates
Copyright
© 2020 Otulak-Kozieł, Kozieł, Escalante and Valverde.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Katarzyna Otulak-Kozieł, katarzyna_otulak@sggw.edu.plEdmund Kozieł, edmund_koziel@sggw.edu.pl
This article was submitted to Virology, a section of the journal Frontiers in Plant Science
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.