Transcriptome analysis of two near-isogenic lines of bell pepper (Capsicum annuum) infected with bell pepper endornavirus and pepper mild mottle virus.
Transcriptome analysis of two near-isogenic lines of bell pepper (<i>Capsicum annuum</i>) infected with bell pepper endornavirus and pepper mild mottle virus.
Project description: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.
Project description:Capsicum annuum is one of the main vegetable crops for the local market and exportation in Egypt. In this concern, pepper mild mottle virus (PMMoV) infection caused a significant decrease in Capsicum sp. leading to large economic losses. An isolate of PMMoV was obtained from naturally infected pepper plants, exhibiting different patterns of mottling, leaf distortion, yellowing, and stunting of leaves. The virus was identified. The molecular detection of PMMoV was done using RT-PCR with specific primers designed for coat protein genes. An RT-PCR product (474) bp of the coat protein gene of (PMMoV) was cloned. The target of the investigation was the effect of spring and autumn ethanol extracts of Populus nigra leaves on C. annuum seedling growth and infected C. annuum with (PMMoV) under greenhouse conditions. The experimental data showed that treated spring leaf extract of P. nigra enhanced infected C. annuum seedling growth parameters and fruit quality compared to uninfected seedlings. P. nigra spring leaf extract containing some allo-chemicals had a negative effect on uninfected seedlings. P. nigra autumn leaf extract significantly improved the growth and fruit quality of infected C. annuum seedlings compared to the control.
Project description:Peppers (Capsicum annuum L.) are the most widespread and cultivated species of Solanaceae in subtropical and temperate countries. These vegetables are economically attractive worldwide. Although whole-genome sequences of peppers and genome-editing tools are currently available, the precision editing of peppers is still in its infancy because of the lack of a stable pepper transformation method. Here, we employed three Agrobacterium tumefaciens strains-AGL1, EHA101, and GV3101-to investigate which Agrobacterium strain could be used for pepper transformation. Hot pepper CM334 and bell pepper Dempsey were chosen in this study. Agrobacterium tumefaciens GV3101 induced the highest number of calli in cv. Dempsey. All three strains generated similar numbers of calli for cv. CM334. We optimized a suitable concentration of phosphinothricin (PPT) to select a CRISPR/Cas9 binary vector (pBAtC) for both pepper types. Finally, we screened transformed calli for PPT resistance (1 and 5 mg/L PPT for cv. CM334 and Dempsey, respectively). These selected calli showed different indel frequencies from the non-transformed calli. However, the primary indel pattern was consistent with a 1-bp deletion at the target locus of the C. annuumMLO gene (CaMLO2). These results demonstrate the different sensitivity between cv. CM334 and Dempsey to A. tumefaciens-mediated callus induction, and a differential selection pressure of PPT via pBAtC binary vector.
Project description:The complete genome sequences of pepper mild mottle virus (PMMoV)-P2 and -P3 were determined by the Sanger sequencing method. Although PMMoV-P2 and PMMoV-P3 have different pathogenicity in some pepper cultivars, the complete genome sequences of PMMoV-P2 and -P3 are composed of 6,356 nucleotides (nt). In this study, we report the complete genome sequences and genome organization of PMMoV-P2 and -P3 isolates from pepper species in South Korea.
Project description:Ribosomal RNA-depleted total RNAs from a sweet pepper plant (Capsicum annuum, labelled as N65) grown in western Slovakia and showing severe virus-like symptoms (chlorosis, mottling and deformation of leaf lamina) were subjected to high-throughput sequencing (HTS) on an Illumina MiSeq platform. The de novo assembly of ca. 5.5 million reads, followed by mapping to the reference sequences, revealed the coinfection of pepper by several viruses; i.e., cucumber mosaic virus (CMV), watermelon mosaic virus (WMV), pepper cryptic virus 2 (PCV2) and bell pepper endornavirus (BPEV). A complete polyprotein-coding genomic sequence (14.6 kb) of BPEV isolate N65 was determined. A comparison of BPEV-N65 sequences with BPEV genomes available in GenBank showed 86.1% to 98.6% identity at the nucleotide level. The close phylogenetic relationship with isolates from India and China resulted in their distinct grouping compared to the other BPEV isolates. Further analysis has revealed the presence of BPEV in sweet or chili peppers obtained from various sources and locations in Slovakia (plants grown in gardens, greenhouse or retail shop). Additionally, the partial sequencing of two genomic portions from 15 BPEV isolates revealed that the Slovak isolates segregated into two molecular clusters, indicating a genetically distinct population (mean inter-group nucleotide divergence reaching 12.7% and 14.5%, respectively, based on the genomic region targeted). Due to the mix infections of BPEV-positive peppers by potato virus Y (PVY) and/or CMV, the potential role of individual viruses in the observed symptomatology could not be determined. This is the first evidence and characterization of BPEV from the central European region.
Project description:The family Endornaviridae infects diverse hosts, including plants, fungi, and oomycetes. Here we report for the first time the assembly of bell pepper endornavirus by next-generation sequencing of viral small RNA. Such a population of small RNA indicates the activation of the viral immunity silencing machinery by this cryptic virus, which probably encodes a novel silencing suppressor.
Project description:Fruits are the dominant sinks for assimilates. At optimal conditions, assimilates supply can meet the demand of fruits and those of the vegetative organs; however, extreme circumstances such as strong sink strength or an environmental stress may disturb this fine balance. While most studies focus on aboveground parameters, information regarding root growth dynamics under variable sink strength are scarce. The objective of this study was to evaluate the effect of sink strength (represented by fruit load) and salinity on bell-pepper root development. Three levels of fruit load were combined with two salinity levels in plants grown in an aeroponic system. Root growth was determined both by root capacitance and destructive measurements. Salinity and sink strength significantly affected root, shoot and fruit growth dynamics. Root growth was less affected by fruit load. Salinity stress was negatively associated with shoot growth, but after an acclimation period, salinity enhanced root development. Additionally, this study shows for the first time that root capacitance is a valid approach for non-destructive measurement of root development in aeroponic systems. The good correlation measured by us (r2 0.86) opens new opportunities for continuous root growth monitoring in aeroponic systems in the future.
Project description:Phosphorus (P) is an important nutritional element needed by plants. Roots obtain P as inorganic phosphate (Pi), mostly in H2PO-4 form. It is vital for plants to have a sufficient supply of Pi since it participates in important processes like photosynthesis, energy transfer, and protein activation, among others. The physicochemical properties and the organic material usually make Pi bioavailability in soil low, causing crops and undomesticated plants to experience variations in accessibility or even a persistent phosphate limitation. In this study, transcriptome data from pepper roots under low-Pi stress was analyzed in order to identify Pi starvation-responsive genes and their relationship with metabolic pathways and functions. Transcriptome data were obtained from pepper roots with Pi deficiency by RNASeq and analyzed with bioinformatic tools. A total of 97 differentially expressed genes (DEGs) were identified; Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed that metabolic pathways, such as porphyrin and chlorophyll metabolism, were down-regulated, and galactose and fatty acid metabolism were up-regulated. The results indicate that bell pepper follows diverse processes related to low Pi tolerance regulation, such as the remobilization of internal Pi, alternative metabolic pathways to generate energy, and regulators of root development.
Project description:BackgroundExpansins (EXPs) facilitate non-enzymatic cell wall loosening during several phases of plant growth and development including fruit growth, internode expansion, pollen tube growth, leaf and root development, and during abiotic stress responses. In this study, the spatial and temporal expression patterns of C. annuum α- EXPANSIN (CaEXPA) genes were characterized. Additionally, fruit-specific CaEXPA expression was correlated with the rate of cell expansion during bell pepper fruit development.ResultsSpatial expression patterns revealed that CaEXPA13 was up-regulated in vegetative tissues and flowers, with the most abundant expression in mature leaves. Expression of CaEXPA4 was associated with stems and roots. CaEXPA3 was expressed abundantly in flower at anthesis suggesting a role for CaEXPA3 in flower development. Temporal expression analysis revealed that 9 out of the 21 genes were highly expressed during fruit development. Of these, expression of six genes, CaEXPA5, CaEXPA7, CaEXPA12, CaEXPA14 CaEXPA17 and CaEXPA19 were abundant 7 to 21 days after anthesis (DAA), whereas CaEXPA6 was strongly expressed between 14 and 28 DAA. Further, this study revealed that fruit growth and cell expansion occur throughout bell pepper development until ripening, with highest rates of fruit growth and cell expansion occurring between 7 and 14 DAA. The expression of CaEXPA14 and CaEXPA19 positively correlated with the rate of cell expansion, suggesting their role in post-mitotic cell expansion-mediated growth of the bell pepper fruit. In this study, a ripening specific EXP transcript, CaEXPA9 was identified, suggesting its role in cell wall disassembly during ripening.ConclusionsThis is the first genome-wide study of CaEXPA expression during fruit growth and development. Identification of fruit-specific EXPAs suggest their importance in facilitating cell expansion during growth and cell wall loosening during ripening in bell pepper. These EXPA genes could be important targets for future manipulation of fruit size and ripening characteristics.
Project description:Bell pepper endornavirus (BPEV) is a double-stranded RNA virus infecting economically important crops, such as peppers. Next-generation sequencing of small RNAs extracted from the leaves of a pepper plant showing mild viral symptoms, along with subsequent analysis, identified BPEV. The complete genome of this isolate was cloned and sequenced.