Molecular characterization of grapevine plants transformed with GFLV resistance genes: I

The Grapevine FanLeaf Virus-Coat Protein (GFLV CP) gene was inserted through Agrobacterium-mediated transformation in Vitis vinifera ‘Nebbiolo’, ‘Lumassina’ and ‘Blaufränkisch’. Two plasmids were used: pGA-CP+ (full-length GFLV CP gene with an introduced start codon) and pGA-AS (same gene in antisense orientation). Forty-three transgenic lines were regenerated. As several lines in Southern blots share same hybridization patterns, eight independent line groups resulted for ‘Nebbiolo’, one for ‘Lumassina’, and two for ‘Blaufränkisch’. Inserted T-DNA copies ranged from one to three; one line probably contains an incomplete copy of T-DNA. Except for one ‘Nebbiolo’ line, no evidence for methylation of the transgene at cytosine residues was found by Southern analyses. Specific mRNA was present at variable expression levels; some lines accumulated the coat protein while in others the protein was not detectable by ELISA.     

Transgenic tobaccos transformed with a gene encoding a truncated form of the coat protein of tomato black ring nepovirus are resistant to viral infection

 Tomato black ring virus (TBRV) belongs to the nepoviruses, an important genus of phytoviruses characterized by isometric particles and by their transmission by longidorid nematodes. As for all other nepoviruses, the coat protein (CP) of TBRV is encoded by the 3′ terminal part of the viral RNA2 (positions 2801–4334). A hybrid gene driving the expression of a truncated form of the TBRV CP was constructed. It contains a frameshift deletion at position T₄₀₆₅ so that in the encoded protein the last 90 amino acids of the wild-type CP are replaced by 52 amino acids encoded by a different reading frame of the viral RNA. This hybrid gene was introduced into the genome of Nicotiana tabacum cv 'Xanthi' plants. When compared to control plants, progeny of some transformants expressing the mutated CP gene (CPm+ plants) showed resistance against TBRV infection. This resistance is characterized by a delay in the appearance of symptoms, a reduction in the number of infected plants and a reduction in virus accumulation. Received: 28 February 1997 / Revision received: 1 August 1997 / Accepted: 24 March 1999     

Recent advances and prospects in Prunus virology

The stone fruit genus Prunus, within the family Rosaceae, comprises more than 230 species, some of which have great importance or value as ornamental or fruit crops. Prunus are affected by numerous viruses and viroids linked to the vegetative propagation practices in many of the cultivated species. To date, 44 viruses and three viroids have been described in the 9 main cultivated Prunus species. Seven of these viruses and one viroid have been identified in Prunus hosts within the last 5 years. This work addresses recent advances and prospects in the study of viruses and viroids affecting Prunus species, mostly concerning the detection and characterisation of the agents involved, pathogenesis analysis and the search for new control tools. New sequencing technologies are quickly reshaping the way we can identify and characterise new plant viruses and isolates. Specific efforts aimed at virus identification or data mining of high‐throughput sequencing data generated for plant genomics‐oriented purposes can efficiently reveal the presence of known or novel viruses. These technologies have also been used to gain a deeper knowledge of the pathogenesis mechanisms at the gene and miRNA expression level that underlie the interactions between Prunus spp. and their main viruses and viroids. New biotechnological control tools include the transfer of resistance by grafting, the use of new sources of resistance and the development of gene silencing strategies using genetic transformation. In addition, the application of next generation sequencing and genome editing techniques will contribute to improving our knowledge of virus–host interactions and the mechanisms of resistance. This should be of great interest in the search to obtain new Prunus cultivars capable of dealing both with known viruses and viroids and with those that are yet to be discovered in the uncertain scenario of climate change.     

番茄环斑病毒纳米荧光颗粒试纸条的研制

目的:研发一种快速、便捷检测番茄环斑病毒(ToRSV)的方法。方法:以荧光纳米颗粒为标记物,采用免疫层析试验方法制备ToRSV荧光纳米颗粒试纸条,在紫外灯下观察试纸条上的荧光信号,作为结果判定依据。结果:用制备的荧光纳米颗粒试纸条检测包括ToRSV在内的9种病毒,仅ToRSV有阳性反应,其余待测样品均呈阴性,表明该试纸条具有较好的特异性;用该荧光试纸条与传统胶体金试纸条进行灵敏度测试时,其灵敏性高于胶体金试纸条1倍以上,且稳定性试验结果良好。结论:ToRSV荧光纳米颗粒试纸条的研制,为快速检测ToRSV提供了有效手段,该方法可用于现场检验,具有广阔的应用前景。