Expression profiles of five FT-like genes and functional analysis of PhFT-1 in a Phalaenopsis hybrid

Background: Phalaenopsis is an important ornamental flowering plant that belongs to the Orchidaceae family and is cultivated worldwide. Phalaenopsis has a long juvenile phase; therefore, it is important to understand the genetic elements regulating the transition from vegetative phase to reproductive phase. In this study, FLOWERING LOCUS T (FT) homologs in Phalaenopsis were cloned, and their effects on flowering were analyzed. Results: A total of five FT-like genes were identified in Phalaenopsis. Phylogenetic and expression analyses of these five FT-like genes indicated that some of these genes might participate in the regulation of flowering. A novel FT-like gene, PhFT-1, distantly related to previously reported FT genes in Arabidopsis and other dicot crops, was also found to be a positive regulator of flowering as heterologous expression of PhFT-1 in Arabidopsis causes an early flowering phenotype. Conclusions: Five FT homologous genes from Phalaenopsis orchid were identified, and PhFT-1 positively regulates flowering.

Genetic variation in VP7 gene of rotavirus serotype G3 predominated in Changchun, China / 病毒学报

Group A rotavirus (RV) is the most important etiologic agent of severe gastroenteritis among children and the development of an effective vaccine becomes the top public health priority. Since survey of RV serotypes circulating in local community is important for introduction or development of RV vaccine, RV serotype G3 had proved as the predominant strain in Changchun from 2001 to 2005. Stool specimens collected from children with acute diarrhea were tested for group A rotavirus by enzyme-linked immunosorbent assay (ELISA) and RV isolates were typed by reverse transcription-polymerase chain reaction (RT-PCR) using serotype-specific primers. The complete VP7 gene segments of 31 rotavirus strains selected in Changchun from 1999 to 2005 were amplified with RT-PCR. Amplicons were cloned and sequenced. Comparative analysis of the VP7 sequences showed that there were no obvious differences among 31 RV strains. There was similar genetic variation among VP7 genes during the same RV season. The nucleotide sequence of VP7 gene of six G3 RV strains had one base deletion at nt1038 in 2003 RV season. The nucleotide mutations in regions A, B and C of VP7 gene took place at the same position or position near-by. Increase of nucleotide mutation in non- high variation region may benefit maintenance of serotype G3 as pre dominant strain after 2002. Increase of non continuous variation in non-high variation regions was notable.