A mosaic disease of winter wheat was first described in the USA by McKinney in 1925 and subsequently in many other wheat-growing countries. Until recently, the disease was associated worldwide to wheat soil-borne mosaic virus (WSBMV). Results of sequence analysis by German and Chinese researchers, however, have prompted the ICTV to approve a taxonomic proposal to divide American, European, and Chinese isolates into different species within the genus Furovirus. The novel species have been denominated wheat soil-borne mosaic virus, cereal soilborne mosaic virus (CSBMV), and wheat Chinese mosaic virus (WCMV). On the basis of the new classification, the wheat mosaic disease is believed to be generally caused by WSBMV in United States, Brazil, and Canada; by CSBMV in Europe; and by WCMV in Asia. Twenty-four wheat samples showing typical Furovirus symptoms were collected from farmers in fields northern, central, and southern Italy to study their degree of genetic diversity. ssRNA was extracted, and the nucleotide sequence of a viral coat protein gene was determined for each sample. Nucleotide and amino-acid sequences alignment between the sequences obtained and the published RNA2 CP sequences of CSBMV, WSBMV, and WCMV isolates was generated applying the Clustal V method, and phylogenetic distance trees were constructed. Branching orders identified three major phylogenetic groups. In the first group, all the Italian isolates clustered closely together along with French, English, and German isolates (SBCMV species), whereas the second group included the American isolates, and the third ascribed the Asian isolates. Sequence data analysis revealed a high degree of genetic identity among Italian isolates (96.6 to 100.0 %) and between Italian isolates and SBCMV accessions from the United Kingdom, France, and Germany (88.7 to 99.6 %). Sequence divergences from 29.6 to 45.9 % were observed between Italian SBCMV isolates and SBWMV or CWMV isolates. Amino-acid sequence analysis of CP cistron revealed few nonspecific exchanges as well as a high degree of sequence identity (97.7 to 100%) among CSBMV isolates from Italy and other European countries. Amino-acid sequence similarity between Italian and Asian or American isolates ranged from 71.0 to 81.2 %. Eventhough all the Italian isolates so far analyzed belong to the novel CSBMV species, the presence of SBWMV in this country cannot be excluded.
Molecular characterization of Italian soilborne cereal mosaic virus isolates / Ratti C.; A. Pisi; C. Rubies-Autonell; V. Vallega. - In: ANNUAL WHEAT NEWSLETTER. - STAMPA. - 54:(2008), pp. 72-72.
Molecular characterization of Italian soilborne cereal mosaic virus isolates
RATTI, CLAUDIO;PISI, ANNAMARIA;RUBIES AUTONELL, CONCEPCION;
2008
Abstract
A mosaic disease of winter wheat was first described in the USA by McKinney in 1925 and subsequently in many other wheat-growing countries. Until recently, the disease was associated worldwide to wheat soil-borne mosaic virus (WSBMV). Results of sequence analysis by German and Chinese researchers, however, have prompted the ICTV to approve a taxonomic proposal to divide American, European, and Chinese isolates into different species within the genus Furovirus. The novel species have been denominated wheat soil-borne mosaic virus, cereal soilborne mosaic virus (CSBMV), and wheat Chinese mosaic virus (WCMV). On the basis of the new classification, the wheat mosaic disease is believed to be generally caused by WSBMV in United States, Brazil, and Canada; by CSBMV in Europe; and by WCMV in Asia. Twenty-four wheat samples showing typical Furovirus symptoms were collected from farmers in fields northern, central, and southern Italy to study their degree of genetic diversity. ssRNA was extracted, and the nucleotide sequence of a viral coat protein gene was determined for each sample. Nucleotide and amino-acid sequences alignment between the sequences obtained and the published RNA2 CP sequences of CSBMV, WSBMV, and WCMV isolates was generated applying the Clustal V method, and phylogenetic distance trees were constructed. Branching orders identified three major phylogenetic groups. In the first group, all the Italian isolates clustered closely together along with French, English, and German isolates (SBCMV species), whereas the second group included the American isolates, and the third ascribed the Asian isolates. Sequence data analysis revealed a high degree of genetic identity among Italian isolates (96.6 to 100.0 %) and between Italian isolates and SBCMV accessions from the United Kingdom, France, and Germany (88.7 to 99.6 %). Sequence divergences from 29.6 to 45.9 % were observed between Italian SBCMV isolates and SBWMV or CWMV isolates. Amino-acid sequence analysis of CP cistron revealed few nonspecific exchanges as well as a high degree of sequence identity (97.7 to 100%) among CSBMV isolates from Italy and other European countries. Amino-acid sequence similarity between Italian and Asian or American isolates ranged from 71.0 to 81.2 %. Eventhough all the Italian isolates so far analyzed belong to the novel CSBMV species, the presence of SBWMV in this country cannot be excluded.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
