| Peanut or groundnut (Arachis hypogea L.) is one of major oil crops in China. Peanutviral diseases are economically important and occur in every peanut production areas.Three viruses naturally infecting peanut have been identified, which included Peanutstripe virus (PStV), Cucumber mosaic virus (CMV) and Peanut stunt virus (PSV).Besides, there is a peanut disease caused by a tospovirus occurs widely in the peanutproduction region of the southern China. The disease is characterized with yellow spotsand necroses on the top leaves and buds of infected plants. The bud growth of peanut issuppressed at the late growing stage and the infected peanut plants are significant stuntcompared with health plants. In this study, the causal virus of the disease wascharacterized as a new strain of Capsicum chlorosis virus (CaCV), designated Chinesepeanut(CP) strain, based on host reactions, particle morphology, serology and completesequence analysis of viral S RNA. The mian results are described as follows:1. The peanut disease surveyed indicated that the disease caused by Capsicum chlorosisvirus occurred widely in Guangzhou surburb and Dongyuan county of Guangdongprovince during 2004-2005. The diseased peanut incidence was around 1％and couldreach to 5％in some peanut fields. The leaves and bud was necroses, and the plantwas stunt of diseased peanut. The few pod was produced in infected peanut plant.2. Of 31 plant species inoculated mechanically, 24 were susceptible to CaCV-CP.CaCV-CP systemically infected Arachis hypogaea, Phaseolus vulgaris, Glycine max,Pisum sativum, Phaseolus mungo, Lupius albus, Cassia tora, Sesbania cannabina,Nicotiana tobacum, N. rustica, N.glutinosa, N. occidentalis, N. benthamiana,Lycopersicon esculetum, Petunia hybrida, Datura stramonium, Capsicum annuum,Cyamopsis tetragonobi. Symptoms on systemic hosts were shown mostly ring oryellow spots and necroses on leaves. Local chlorotic ring spots and necrotic spotswere found on inoculated leaves of Chenopodium amaraticolor, C. quinoa,Gomphrena globosa, Vigna sinensis, V.unquicuiata and Cassia occidentalis. Sevenplant species including Vicia faba, Cajanus cajan, Cicor arietinum, Zinnia elegans,Cucumis sativus, Sesanum indicum and Vinca rosea were not infected.3. CaCV-CP had thermal inactivation point 45℃～50℃, dilution end point 10-3～10-4 and longevity in vitro 5～6h. The quasi-spherical virions with 80～100nm in diameterwere present in ultrathin section of diseased leaves.4. The virus particle was purified from CaCV-CP infected N. occidentalis leves using amodified method. The polyclonal andibody against CaCV-CP was produced by thevirus immusing the New Zealand rabbit. The titer of the antiserum was 1:1000 inELISA test. CaCV-CP had serological relationshop with Groundnut bud necrosisvirus (GBNV) and Watermelon silver mottle virus (WSMoV), had no serologicalrelationshop with Tomato spotted wilt virus (TSWV).5. The CaCV-CP double strand (ds) RNA was extracted using CF-11 cellulose powderfrom diseased N. occidentalis leaves. The complete sequence of S RNA of CaCV-CPwas analysised. Genomic S RNA of CaCV-CP consisted of 3399 nucleotides (nts)with a 5'-UTR of 66 nts and a 3'-UTR of 66 nts. CaCV-CP S RNA contained twoORFs with an ambisense coding strategy. The first ORF (nt 67-1386) encoded anonstructure (NSs) protein of 49,854 Da. The second ORF (nt 2506-3333) encodeda nucleocapsid (N) protein of 30,724 Da. The intergenic region (IGR) between twoORFs was 1119 nts. The complete sequence of CaCV-CP S RNA has sunmitted tothe GenBank and the accession number of the sequence is DQ355974.6. The length of N and NSs gene of CaCV-CP and other reported CaCV isolates was828 nt and 1320 nt, respectively. The N gene of CaCV-CP shared 84.7～86.4% and92.4～93.1% identity with that of CaCV isolates from Thailand and Australia atnucleotide and amino acid levels, respectively. The identities for NSs gene ofCaCV-CP with CaCV-AIT was 84.4% and 88.4% at nucleotide and amino acid levels,respectively. The identity of N and NSs genes of CaCV-CP with that of other fourtospoviruses (WSMoV, PBNV, WBNV and CCSV) in WSMoV serogroup was63.5%～79.8% and 61.3%～77.1% at nucleotide level, and 64.6%～82.6% and6116%～82.2% at amino acid level, respectively. The degree of identities of N genewith other Tospovirus serogroup (serotype) members was below 61% and 60% atnucleotide and amino acid levels, respectively; and was below 57% and 51% for NSsgene at nucleotide and amino acid levels, respectively. The length of intergenicregion (IGR) varied greatly and shared the lowest sequence identity among themembers in Tospovirus WSMoV serogroup.
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