Research in Plant Disease (식물병연구)
- Volume 7 Issue 3
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- Pages.155-163
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- 2001
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- 2233-9191(eISSN)
Cross-Protection Effectiveness of Cucumber mosaic virus (CMV) Isolates Associated with Satellite RNA for Prevention of CMV Disease in Pepper Plants
Satellite RNA 보유 Cucumber mosaic virus(CMV)의 고추 CMV병에 대한 교차방어 효과
Abstract
Two attenuated Cucumber mosaic virus (CMV) isolates, Paf-CMV and Rs2-CMV that had been selected from CMV isolates associated with satellite RNA (satRNA) were tested for cross-protection effect in pepper plants. The viruses selected as attenuated strains appeared to be identical serologically and physically to the challenge virus (Mf-CMV), but they were lower in the dilution end-point of infectivity of crude sap than Mf-CMV When symptoms were observed in several indicator plants after inoculation, Paf-CMV and Rs2-CMV were symptomless or showed mild mosaic symptoms while another satRNA isolate Ap-CMV developed severe mosaic symptoms on the leaves as Mf-CMV. The nucleotide sequences of the satRNAs were determined by sequencing full-length cDNA clones. Paf-, Rs2- and Ap-satRNAs were 386, 335, and 347 nucleotides long, respectively, The sequences were then compared with the other known Y-satRNA, revealing that nucleotide sequences of the satRNAs consisted of 5'- and 3'-terminal conserved regions. However variations occurred on the middle regions of the sequences, especially those related to symptom interference, showing significant differences between Paf-satRNA and other isolates. Infectious transcripts of Paf-satRNA and Rs2-satRNA induced mild mosaic symptoms in pepper plants when supported by genomic RNAs of Mf-CMV. Under greenhouse conditions, Paf-CMV and Rs2-CMV were tested for cross-protection effect in pepper and tobacco (Nicotiana tabacum cv, Xanthi nc) plants against Mf-CMV. No symptoms were developed on the plants vaccinated with Paf-CMV until 3 weeks after inoculation with the virulent strain; however another attenuated isolate, Rs2-CMV, showed less effectiveness in cross-protection. Depending on the concentration of the challenged virus, symptoms sometimes appeared later in the upper leaves. However, in plants challenged with low concentrations (below 0.2 mg/ml) of the challenge inoculum, symptoms caused by the virulent strain did not develop on the plants vaccinated with Paf-CMV. In the field experiments, the number of pepper plants with severe mosaic symptoms in the control plots was progressively increased after transplanting and reached approximately 50% after 50 days. On the other hand, the incidence of mosaic disease appeared very low on the plants that had received the protective inoculation with Paf-CMV.
기주반응 실험을 통하여 무병징 또는 엷은 병징을 발현하는 satRNA 보유 Paf-CMV 및 Rs2-CMV를 고추 CMV병의 방제를 위한 약독바이러스로 공시하여 교차방어효과를 검정하였다. 공시한 satRNA-CMV는 모두 agar gel diffusion test에서 강독계로 공시한 Mf-CMV의 항원과 융합하는 침강선을 나타내 subgroup I의 혈청 형으로 판단되었다. 이들 약독계 satRNA-CMV의 물리적성질은 내희석성이