Biology, Structure, Functions and Possible Origin of Viroids

Sänger, Heinz L.

doi:10.1007/978-3-642-68347-3_12

Cited by 32 publications

(10 citation statements)

References 196 publications

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“…It can be speculated that a possible imbalance in nuclease expression may in turn impair the processes of tissue differentiation. Furthermore, the bifunctional nuclease could participate in apoptotic processes in the later stages of viroid pathogenesis, when veinal necroses appear as a well-known symptom associated with viroid infection (Sä nger, 1982). Although we did not directly prove the function of TBN1 in differentiation of the vascular system of diseased tissue, our light microscopy observations revealed an arrest of vascular bundle establishment in petioles from AS1collapsed plants, as well as some deficiency of the diseased vascular system in xylem tissue.…”

Section: A Possible Role Of Elevated Levels Of Nuclease In Viroid-caumentioning

confidence: 58%

Accumulation of viroid-specific small RNAs and increase in nucleolytic activities linked to viroid-caused pathogenesis

Matoušek

Kozlová

Orctová

et al. 2007

Biological Chemistry

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Strong viroid-caused pathogenesis was achieved in tomato cv. Rutgers by biolistic transfer of severe or lethal potato spindle tuber viroid (PSTVd) strains, while other tomato genotypes (e.g., Moneymaker) were tolerant. With reciprocal hybrids between sensitive and tolerant genotypes, we show that plant depression dominates over tolerance. Biolistic transfer of the most pathogenic PSTVd strain AS1 to Nicotiana benthamiana, which is considered to be a symptomless PSTVd host, led to a strong pathogenesis reaction and stunting, suggesting the presence of specific viroid pathogenesis-promoting target(s) in this plant species. Total levels of small siRNA-like PSTVd-specific RNAs were enhanced in strongly symptomatic tomato and N. benthamiana plants after biolistic infection with AS1 in comparison to the mild QFA strain. This indicates association of elevated levels of viroid-specific small RNA with production of strong symptoms. In symptom-bearing tomato leaves in comparison to controls, an RNase of approximately 18 kDa was induced and the activity of a nuclease of 34 kDa was elevated by a factor of seven in the vascular system. Sequence analysis of the nuclease cDNA designated TBN1 showed high homology with plant apoptotic endonucleases. The vascular-specific pathogenesis action is supported by light microscopic observations demonstrating a certain lack of xylem tissue and an arrest of the establishment of new vascular bundles in collapsed plants.

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Section: A Possible Role Of Elevated Levels Of Nuclease In Viroid-caumentioning

confidence: 58%

Accumulation of viroid-specific small RNAs and increase in nucleolytic activities linked to viroid-caused pathogenesis

Matoušek

Kozlová

Orctová

et al. 2007

Biological Chemistry

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“…Sequence comparisons between the intermediate (Type) and a severe to lethal strain (KF440-1) of PSTVd have previously shown that only four nucleotide changes occur in this region (see Fig. 1) (Sanger, 1982;Schnolzer et al, 1985). To test the "plasticity" of this region, we had previously introduced one of these changes, a single G + C transversion at residue 46 (Hammond and Owens, 1987).…”

Section: Introductionmentioning

confidence: 98%

Analysis of the virulence modulating region of potato spindle tuber viroid (PSTVd) by site-directed mutagenesis

Hammond¹

1992

Virology

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A series of nucleotide substitutions (G,, --f C; Cd7 + A; C,,, + U; U3,7 + C) were introduced into the virulence modulating region of the intermediate strain of potato spindle tuber viroid (PSTVd) in order to examine their effect upon viroid infectivity and pathogenicity with the presence of all four mutations resulting in the sequence of a previously reported severe strain of PSTVd. Eight of the resulting mutant cDNAs were characterized for infectivity and symptom induction in tomato, and the secondary structure of their corresponding RNAs was examined. The combined results of infectivity, computer analysis, and chemical mapping data imply that a previously proposed correlation between thermodynamic stability and PSWd pathogenicity does not hold true in all cases and suggest that conformation and/or sequence-specific interactions with host factors play a role in symptom development.o 1992 Academic PES, I~c.

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“…Various viroids from Pospiviroidae cause plant developmental distortions, alter morphogenetic and physiological parameters, and thus cause serious plant diseases in numerous crops depending on plant species and viroid genotypes. Certain viroid-host combinations are accompanied by severe host symptoms, while in other combinations the same viroid variant is tolerated by the host and symptoms are weak or not detectable (Sänger, 1982;Hadidi et al, 2003).…”

Section: Introductionmentioning

confidence: 98%

Expression of SANT/HTH Myb mRNA, a plant morphogenesis-regulating transcription factor, changes due to viroid infection

Matoušek

Piernikarczyk

Týcová

et al. 2015

Journal of Plant Physiology

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Biology, Structure, Functions and Possible Origin of Viroids

Cited by 32 publications

References 196 publications

Accumulation of viroid-specific small RNAs and increase in nucleolytic activities linked to viroid-caused pathogenesis

Accumulation of viroid-specific small RNAs and increase in nucleolytic activities linked to viroid-caused pathogenesis

Analysis of the virulence modulating region of potato spindle tuber viroid (PSTVd) by site-directed mutagenesis

Expression of SANT/HTH Myb mRNA, a plant morphogenesis-regulating transcription factor, changes due to viroid infection

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