The Level of Abutilon Mosaic Geminivirus in Leaf Discs and Wound Callus

Song, Jiangping; Jeske, Holger

doi:10.1111/j.1439-0434.1994.tb01444.x

Cited by 8 publications

(3 citation statements)

References 32 publications

(14 reference statements)

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“…For the experiments shown in Figure 1, eluted DNA was digested with 10 μg/ml RNase A or 100 μg/ml proteinase K (Boehringer) for 30 min at 20°C. Southern blotting using alkaline (Chomczynski and Qasba, 1984) or neutral transfer, and subsequent hybridization, were performed as described (Song and Jeske, 1994). Probes were digoxigenin‐labelled (Boehringer kit #158606), gel‐purified fragments either of cloned full‐length AbMV DNA A (Frischmuth et al ., 1990) excised with Pst I, of the AC1 region amplified by PCR from the full‐length DNA A clone, or of the BV1 gene (Wege and Jeske, 1998).…”

Section: Methodsmentioning

confidence: 99%

DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus

2001

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Geminiviruses have spread worldwide and have become increasingly important in crop plants during recent decades. Recombination among geminiviruses was one major source of new variants. Geminiviruses replicate via rolling circles, con®rmed here by electron microscopic visualization and two-dimensional gel analysis of Abutilon mosaic virus (AbMV) DNA. However, only a minority of DNA intermediates are consistent with this model. The majority are compatible with recombination-dependent replication (RDR). During development of naturally infected leaves, viral intermediates compatible with both models appeared simultaneously, whereas agro-infection of leaf discs with AbMV led to an early appearance of RDR forms but no RCR intermediates. Inactivation of viral genes ac2 and ac3 delayed replication, but produced the same DNA types as after wild-type infection, indicating that these genes were not essential for RDR in leaf discs. In conclusion, host factors alone or in combination with the viral AC1 protein are necessary and suf®cient for the production of RDR intermediates. The consequences of an inherent geminiviral recombination activity for the use of pathogen-derived resistance traits are discussed.

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Section: Methodsmentioning

confidence: 99%

DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus

2001

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“…To determine the infection status of individual plants, Southern and tissue blot hybridizations were performed. Total nucleic acids were isolated from single systemically infected leaves, as described previously (51). Tissue blots were made by gently printing fresh cross-sections of leaves or petioles onto dry nylon membranes (Hybond-NX; Amersham) and UV cross-linking the attached nucleic acids (UV cross-linker UV setting, 700 J/cm 2 ; Amersham).…”

Section: Purification Of Nucleimentioning

confidence: 99%

Tête à Tête of Tomato Yellow Leaf Curl Virus and Tomato Yellow Leaf Curl Sardinia Virus in Single Nuclei

Morilla

Krenz

Jeske

et al. 2004

J Virol

105

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Since 1997 two distinct geminivirus species, Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern Spain, and very frequently doubly infected single plants. Tomatoes as well as experimental test plants (e.g., Nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. Viral DNA accumulated to a similar extent in singly and doubly infected plants. In situ tissue hybridization showed TYLCSV and TYLCV DNAs to be confined to the phloem in both hosts, irrespective of whether they were inoculated individually or in combination. The number of infected nuclei in singly or doubly infected plants was determined by in situ hybridization of purified nuclei. The percentage of nuclei containing viral DNA (i.e., 1.4% in tomato or 6% in N. benthamiana) was the same in plants infected with either TYLCSV, TYLCV, or both. In situ hybridization of doubly infected plants, with probes that discriminate between both DNAs, revealed that at least one-fifth of infected nuclei harbored DNAs from both virus species. Such a high number of coinfected nuclei may explain why recombination between different geminivirus DNAs occurs frequently. The impact of these findings for epidemiology and for resistance breeding concerning tomato yellow leaf curl diseases is discussed.

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“…So far, we have not succeeded in extracting nick-free AbMV DNA from plants, even by very rigorous techniques (39). It therefore remains to be determined which nicks existed before the addition of exogenous nucleases in vivo or which had been produced in early steps of purification when endogenous nucleases had attacked the DNA.…”

Section: Discussionmentioning

confidence: 99%

Mapping of Abutilon Mosaic Geminivirus Minichromosomes

Pilartz

Jeske

2003

J Virol

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The single-stranded circular DNA of Abutilon mosaic geminivirions is complemented to double-stranded DNA by host proteins after infecting cells. This double-stranded DNA serves as a template for replication as well as transcription and is assembled into host nucleosomes, yielding circular viral minichromosomes. Their chromatin structure was analyzed by use of isolated nuclei combining nuclease sensitivity assays with ligationmediated PCR, evaluating nucleosomal ladders and topoisomer distributions in one-and two-dimensional gels by blot hybridization. Viral minichromosomes were found to exist in at least two defined structures covered with 11 or 12 nucleosomes, leaving open gaps accessible for interactions with other host factors. Nucleosomefree gaps were colocalized with promoter structures and the origin of replication in both components of genomic DNA (DNA A and DNA B). Nucleosomes were positioned over the entire viral DNA in at least two alternative phases with different periodicities. The distribution of topoisomers of monomeric viral circular double-stranded DNA confirmed the presence of variable chromatin structures revealing maximum frequencies of molecules with either 11, 12, or 13 superhelical turns (corresponding to respective numbers of nucleosomes) at maximal frequency at different stages during leaf development of infected plants. The role of variable chromatin structures for gene regulation of geminiviruses is discussed.Replication and transcription are central processes in all living organisms. In comparison to animals, much less is known about their regulation in plants (38). DNA viruses, such as simian virus 40, have been extremely helpful model systems for understanding regulatory cascades in animals (23). A similar tool for plants was lacking, but geminiviruses are appropriate to fill this gap because they are similar to papovaviruses in several aspects of genetic organization. Geminiviruses differ from papovaviruses in that they are tiny circular singlestranded DNA (ssDNA)-containing viruses with one or two genomic components (34), but replicate via double-stranded DNA (dsDNA) intermediates in nuclei, organize their replicative and transcriptional DNA intermediates in minichromosomes (2, 32), and transcribe their genes bidirectionally. Correspondingly, the genome organization of geminiviruses is very similar to that of papovaviruses (42).Abutilon mosaic virus (AbMV) of the genus Begomovirus (34) possesses a bipartite genome consisting of DNA A and DNA B (see Fig. 4). The DNAs are different from each other, except for a common region of about 200 nucleotides harboring most of the regulatory elements for replication and transcription. As their genome is very small, they rely on host factors, especially a DNA polymerase, for both replication and transcription (reviewed by Hanley-Bowdoin et al. [16]). The common region contains a palindromic sequence forming a hairpin loop, the origin for a rolling-circle type replication, which functions in replication initiation. Recently, we discovered that a...

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The Level of Abutilon Mosaic Geminivirus in Leaf Discs and Wound Callus

Cited by 8 publications

References 32 publications

DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus

DNA forms indicate rolling circle and recombination-dependent replication of Abutilon mosaic virus

Tête à Tête of Tomato Yellow Leaf Curl Virus and Tomato Yellow Leaf Curl Sardinia Virus in Single Nuclei

Mapping of Abutilon Mosaic Geminivirus Minichromosomes

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