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Rhizomania is one of the most damaging and widespread diseases in the major sugar beet (Beta vulgaris L. subsp. vulgaris) growing regions worldwide. The causal agent, Beet necrotic yellow vein virus, is transmitted by a plasmodiophorid vector, Polymyxa betae Keskin. In this study, the inhibition of BNYVV multiplication was evaluated, under field conditions, in six sugar beet transgenic events generated based on gene silencing of the major coat protein gene (CP21). Phenotypic criteria, including scoring for disease symptoms and an immunoassay for viral accumulation, indicated that the transgenic events were less susceptible to rhizomania and had lower virus titre rates than non-transgenic plants of the susceptible cultivar '9597'. Disease severity and virus titres were comparable to the resistant cultivar 'Dorothea', which carries the Rz1-resistance gene and was bred through traditional means. This study provides a proof of concept for the effectiveness of the gene-silencing mechanism for introducing rhizomania resistance in sugar beet at the field level. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We found a number of male-sterile plants in a wild beet (Beta vulgaris L. subsp. maritima) accession line, FR4-31. The inheritance study of the male sterility indicated the trait to be of the cytoplasmic type. The mitochondrial genome of FR4-31 proved to lack the male-sterility-associated genes preSatp6 and orf129, which are characteristic of the Owen CMS and I-12CMS(3) cytoplasms of beets, respectively. Instead, the truncated cox2 gene involved in G CMS originating from wild beets was present in the FR4-31 mitochondrial genome. In Southern hybridization using four mitochondrial gene probes, the FR4-31 cytoplasm showed patterns similar to those typical of the G cytoplasm. It is thus likely that the FR4-31 cytoplasm has a different CMS mechanism from both Owen CMS and I-12CMS(3), and that the FR4-31 and G cytoplasms resemble each other closely. A restriction map of the FR4-31 mitochondrial DNA was generated and aligned with those published for the Owen and normal fertile cytoplasms. The FR4-31 mitochondrial genome was revealed to differ extensively in arrangement from the Owen and normal genomes, and the male-sterile Owen and FR4-31 genomes seem to be derived independently from an ancestral genome. Les auteurs ont trouvé plusieurs plantes mâles stériles chez l’accession FR4-31 de la betterave maritime (Beta vulgaris L. subsp. maritima). L’étude de l’hérédité de cette stérilité mâle a montré que le caractère était cytoplasmique. Le génome mitochondrial de FR4-31 s’est avéré dépourvu de deux gènes associés à la stérilité mâle, preSatp6 et orf129, lesquels sont respectivement caractéristiques des cytoplasmes CMS Owen et I-12CMS(3) chez les betteraves. Au lieu, un gène cox2 tronqué, impliqué dans la CMS G chez les betteraves maritimes, était présent dans le génome mitochondrial de FR4-31. Lors d’hybridations Southern réalisées à l’aide de quatre sondes géniques mitochondriales, le cytoplasme FR4-31 s’est montré semblable à celui du cytoplasme G. Il est ainsi vraisemblable que le cytoplasme FR4-31 possède un mécanisme CMS différent de celui présent chez la CMS Owen et I-12CMS(3), et que les cytoplasmes FR4-31 et G se ressemblent beaucoup. Une carte de restriction de l’ADN mitochondrial de FR4-31 a été générée et alignée avec celles publiées pour les cytoplasmes Owen et normaux fertiles. Le génome mitochondrial de FR4-31 a présenté de nombreuses différences dans son organisation relativement aux génomes Owen et normal. Par contre, les génomes mâles stériles Owen et FR4-31 semblent dérivés indépendamment d’un génome ancestral. [ABSTRACT FROM AUTHOR]

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A sugar beet (Beta vulgaris) fosmid library from the doubled haploid accession KWS2320 encompassing 115 200 independent clones was constructed and characterized. The average insert size of the fosmid library was determined by pulsed field gel electrophoresis to be 39 kbp on average, thus representing 5.9-fold coverage of the sugar beet genome (758 Mbp). PCR screening of plate pools with primer pairs against nine sugar beet genes supported the insert size estimation. BLAST searches with 2951 fosmid end-sequences originating from 1510 clones (1536 clones attempted) revealed little contamination with organellar DNA (2.1% chloroplast DNA, 0.3% mitochondrial DNA). The sugar beet fosmid library will be integrated in the presently ongoing efforts to determine the sequence of the sugar beet genome. Fosmids will be publicly available in the format of plate pools and individual clones. [ABSTRACT FROM AUTHOR]