An efficient system of genetic transformation and plant regeneration via somatic embryogenesis was established in crownvetch (Coronilla varia L.) by infecting the segments of cotyledons and hypocotyls of 15d-old seedlings with Agrobacterium rhizogenes strain 15834. Hairy roots were produced directly from the wounded surface of the explants or via calluses on hormone-free Murashige and Skoog (MS) medium after infection by A. rhizogenes. Transformed roots grew rapidly either on solid or liquid MS medium, and exhibited typical hairy root phenotypes. The highest transformation frequency (87.4%) was achieved by preculturing cotyledons for 2d and pre-treating the A. rhizogenes with suitable concentration of acetosyringone at logarithmic phase (OD600 = 0.8). The embryogenic calluses with 100% induction frequency were induced from hairy roots on MS medium containing 0.2mg/L 2,4-D, 0.5mg/L NAA and 0.5mg/L KT. Globular-, heart-, torpedo-, and cotyledon shaped somatic embryos were produced orderly and developed into plantlets when transferred the embryogenic calluses on MS medium supplemented with 0.5mg/L KT, 0.2mg/L IBA and 300mg/L proline. The transformed plants did not show differences in morphology except abundant lateral root branches compared to the non-transformed plants. However, the contents of 3-nitropropanic acid in hairy roots and leaves of one of 5 transformed clones were 57.68% and 58.17% in roots and leaves of untransformed plants, respectively. Opine paper electrophoresis revealed the integration and expression of TR-DNA. PCR analysis confirmed that the TL-DNA including 654 bp rol B sequence was inserted into the genome of transformed hairy roots and their regenerated plants.
Fabaceae ; genetics ; growth & development ; physiology ; Plant Roots ; genetics ; growth & development ; physiology ; Plants, Genetically Modified ; genetics ; growth & development ; Regeneration ; Rhizobium ; genetics ; Tissue Culture Techniques ; Transformation, Genetic

OBJECTIVETo study the prevalence of severe acute respiratory syndrome coronavirus (SARS-CoV) like virus in animals at a live animal market of Guanzhou in 2004 before and after culling of wild animal action taken by the local authority, in order to predict the re-emerging of SARS from animal originals in this region.

METHODSAnimals at live animal market were sampled for rectal and throat swabs in triplicate. A single step realtime reverse transcription-polymerase chain reaction (RT-PCR) diagnostic kit was performed for screening SARS-CoV like virus, the manual nested RT- PCR and DNA sequencing were performed for confirmation. Only specimens which tested positive for both of the N and P genes by nested RT-PCR were scored as positive.

RESULTSIn 31 animals sampled in January 5 2004 before culling of wild animals at Guangdong Province, including 20 cats (Felis catus), 5 red fox (Vulpes vulpes) and 6 Lesser rice field rats (Rattus losea), 8 (25.8%) animals were tested positive for SARS-CoV like virus by RT-PCR methods, of which 4 cats, 3 red fox and one Lesser rice field rats were included. However, two weeks after culling of animals and disinfection of the market were implemented, in 119 animals sampled in January 20 2004, including 6 rabbits (Oryctolagus cuniculus), 13 cats, 46 red jungle fowl (Gallus gallus), 13 spotbill duck (Anas platyrhynchos), 10 greylag goose (Anser anser), 31 Chinese francolin (Franclinus pintadeanus), only rectal swab from one greylag goose was tested positive for SARS-CoV like virus. Furthermore, in 102 animals that including 14 greylag gooses, 3 cats, 5 rabbits, 9 spotbill duck (Anaspoecilorhyncha), 2 Chinese francolin (Franclinus pintadeanus), 8 common pheasant (Phasianus colchicus), 6 pigeons, 9 Chinese muntjac (Muntiacus reevesi), 19 wild boar (Sus scrofa), 16 Lesser rice field rats, 5 dogs, 1 mink (Mustela vison), 3 goats, 2 green peafowl (Pavo muticus) sampled in April, May, June, July, August and November, only rectal swab from one pig was tested positive. However, of 12 and 10 palm civets sampled in November and December including five of which had been at the live animals market for 2 days, none of them was tested positive.

CONCLUSIONThis findings revealed that animals being sampled in April, May, June, July, August and November of 2004, only one rectal swab from a pig was tested positive as SARS-CoV like virus, much lower than the results from the previous year, suggesting that the possibility of re-emerging of human infection from animal origins is low for the winter of 2004-2005.

Animals ; Animals, Wild ; virology ; China ; DNA, Viral ; analysis ; Felidae ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; SARS Virus ; isolation & purification