The complete genomic sequence of Sugarcane mosaic virus from Canna spp. in China.

BACKGROUND: Sugarcane mosaic virus (SCMV) is the prevalent virus inducing maize dwarf mosaic and sugarcane mosaic diseases in China. According to the phylogenetic results of the complete genomic and coat protein gene sequences, SCMV was divided into four or five molecular groups, respectively. Previously, we detected SCMV isolates of group SO from Canna spp. in Ji'nan, Shandong province, China. FINDINGS: In this study, we collected two SCMV isolates infecting Canna spp. in Ji'nan (Canna-Ji'nan) and Tai'an (Canna-Tai'an) of Shandong, China. Their complete genome sequences had genome of 9576 nucleotides and contained a large open reading frame encoding a polyprotein of 3063 amino acids. The phylogenetic analysis showed that the both Canna-Ji'nan and Canna-Tai'an were clustered into an independent group based on the complete genome sequence. CONCLUSION: In this study, we report the complete genome sequences of SCMV infecting Canna spp. from Ji'nan and Tai'an. This is the first report on SCMV belonging to SO group.

The effect of the size and shape on the bond number of quantum dots and its relationship with thermodynamic properties.

Through introducing the size (Nt) and the shape factor (λ), the size- and shape-dependent bond number Ba of quantum dots, respectively, with icosahedral, truc-decohedral, cuboctahedral, octahedral, decohedral and tetrahedral structures is established in this work. It is found that Nt and λ have reverse contribution to Ba, that is, Ba increases with increase in Nt, while it decreases with increase in λ. As the basic parameter, the size- and shape-dependent Ba function is extended to predict the cohesive energy Ec(Nt) of quantum dots. Similar to Ba, Ec(Nt) shows strong dependence on both the size and shape. Larger Nt leads to higher Ec(Nt), whereas larger λ results in a smaller Ec(Nt) value. There is a sequence: Ec(IH) > Ec(CO) > Ec(truc-DH) > Ec(OT) > Ec(DH) > Ec(TH) if Nt is certain, which is similar to Ba since Ba(IH) > Ba(CO) > Ba(truc-DH) > Ba(OT) > Ba(DH) > Ba(TH) is tested in the whole size range. To some extent, this is due to λ(IH) = λ(truc-DH) < λ(CO) < λ(OT) < λ(DH) < λ(TH), however, Ba(IH) > Ba(truc-DH) despite λ(IH) = λ(truc-DH). In addition, λ is no longer constant and increases with increase in Nt when the shape is given. The fact that whatever the shape is, Ba or Ec(Nt) increases upon increasing Nt, meaning that the shape is a secondary factor if compared with the size. The validity of the size- and shape-related model for the Ec(Nt) function is also confirmed by the simulation results of the size- and shape-dependent thermodynamic stability of Au, Ag, Cu, Ca, Sr, and Si quantum dots with different atomic structures.

Complete genome sequence of a tobacco isolate of the tobacco vein banding mosaic virus strain prevailing in China.

Tobacco vein banding mosaic virus (TVBMV) is a species of the largest plant virus genus Potyvirus. Its incidence has been increasing in Chinese tobacco-growing area. TVBMV isolates can be clustered into three genetic groups that are corresponding with their geographical origin. We have reported the complete genomic sequence of TVBMV isolate YND with unique NIb/CP cleavage site. Here, we determined and analyzed the complete genomic sequence of isolate HN39, which was collected from tobacco in Henan Province and represented Chinese prevalent strain of TVBMV. HN39 has similar host range with YND, but induce mild vein banding symptom in Nicotiana tabacum cv. Samsun. The genome of TVBMV-HN39 is composed of 9,570 nucleotides, excluding the poly(A) tail. It contains a large ORF of 9,240 nucleotides and encode a polyprotein of 3,079 amino acids. The putative NIa-Pro cleavage site for NIb/CP is Q/G. The identities between the complete genomes of isolates HN39 and YND were 90.0% at nucleotide level and 95.4% at amino acid level. As for other potyviruses, HN39 shared the highest identity with wild tomato mosaic virus (WTMV) at complete genomic level, while different genes shared the highest identities with different potyviruses. This is the second complete genomic sequence of TVBMV reported.