Grapevines, although adapted to occasional drought or salt stress, are relatively sensitive to growth- and yield-limiting salinity stress. To understand the molecular mechanisms of salt tolerance and endoplasmic reticulum (ER) stress and identify genes commonly regulated by both stresses in grapevine, we investigated transcript profiles in leaves of the salt-tolerant grapevine rootstock 1616C under salt- and ER-stress. Among 1643 differentially expressed transcripts at 6 h post-treatment in leaves, 29 were unique to ER stress, 378 were unique to salt stress, and 16 were common to both stresses. At 24 h post-treatment, 243 transcripts were unique to ER stress, 1150 were unique to salt stress, and 168 were common to both stresses. GO term analysis identified genes in categories including ‘oxidative stress’, ‘protein folding’, ‘transmembrane transport’, ‘protein phosphorylation’, ‘lipid transport’, ‘proteolysis’, ‘photosynthesis’, and ‘regulation of transcription’. The expression of genes encoding transporters, transcription factors, and proteins involved in hormone biosynthesis increased in response to both ER and salt stresses. KEGG pathway analysis of differentially expressed genes for both ER and salt stress were divided into four main categories including; carbohydrate metabolism, amino acid metabolism, signal transduction and lipid metabolism. Differential expression of several genes was confirmed by qRT-PCR analysis, which validated our microarray results. We identified transcripts for genes that might be involved in salt tolerance and also many genes differentially expressed under both ER and salt stresses. Our results could provide new insights into the mechanisms of salt tolerance and ER stress in plants and should be useful for genetic improvement of salt tolerance in grapevine.

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Beet necrotic yellow vein virus (BnYVV) is the cause of rhizomania, an important disease of sugar beetaround the world. The multipartite genome of the BNYVV contains four or five single-stranded RNA that has been used to characterize the virus. Understanding genome composition of the virus not only determines the degree of pathogenicity but also is required to development of resistant varieties of sugar beet. Resistance to rhizomania has been conferred to sugar beet varieties by conventional breeding methods or modern genome engineering tools. However, over time, viruses undergo genetic alterations and develop new variants to break crop resistance. Here, we report the occurrence of genetic reassortment and emergence of new variants of BnYVV among the isolates of thrace and Asia Minor (modern-day Turkey). Our findings indicate that the isolates harbor European A-type RNA-2 and RNA-3, nevertheless, RNA-5 is closely related to East Asian J-type. Furthermore, RNA-1 and RNA-4 are either derived from A, B, and P-types or a mixture of them. The RNA-5 factor which enhance the pathogenicity, is rarely found in the isolates studied (20%). The creation of new variants of the virus emphasizes the necessity to develop new generation of resistant crops. We anticipate that these findings will be useful for future genetic characterization and evolutionary studies of BNYVV, as well as for developing sustainable strategies for the control of this destructive disease.Rhizomania is one of the most destructive soil-borne diseases of sugar beet (Beta vulgaris L.) worldwide. Since the first report of rhizomania 1 numerous studies have reported the worldwide infection of sugar beet fields with this disease. Tamada and Baba 2 first identified Beet necrotic yellow vein virus (BNYVV) as the cause of rhizomania when they isolated the virus from infected plants of sugar beet fields in Japan. This disease reduces sugar content by 8%, root yield up to 90%, and sugar yield up to 80% 3,4 . The BNYVV genome is multipartite and composed of four single-stranded RNA species designated as RNA-1, RNA-2, RNA-3, and RNA-4, coating with a 21-kDa protein 5 . In addition, a fifth RNA species (RNA-5) has been identified in some of the European and Asian BNYVV isolates 6-12 . RNA-1 and RNA-2, which contain 6746 and 4612 nt-long RNA species, respectively, encode viral "housekeeping" genes involved in virus replication, assembly, cell-to-cell movement and suppression of post transcriptional gene silencing 13,14 . Therefore, when the virus vector Polymyxa betae Keskin 15 is not present, RNA-1 and RNA-2 are required for the maintenance of BNYVV in the environment 8,14,16 . RNA-3 consisting of a 1775 nt-long RNA species, is involved in viral pathogenicity 7,10,11,17,18 . RNA-4 (1431 nt) plays a key role in transmission of the virus by P. betae 7,11,13,19 . RNA-5 (1342-1347 nt in length) is associated with rhizomania severity, but is not required for virus survival 20,21 . Comparative studies revealed that the RNA-1, RNA-4, and RNA-5 contribute to the development ...

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