The most obvious symptom of systemic virus infection is the mosaic pattern of the leaves. Yellowing, chlorosis is also frequent and characteristic sign of the altered photosynthetic activity. Virus infection effects photosynthesis in a complex manner, depending on the particular host-virus combination. The symptoms are basically different in the incompatible or the compatible host-virus interaction.
Last year pepper growers observed symptoms referring to virus-infection in pepper plantations in plastic tunnels. Infected plants showed mosaic symptoms or mottling of the leaves, while on the fruits necrotic spots developed. These symptoms referred to a tobamovirus infection. Collected samples were examined by serological and pathological methods, followed by the biological characterisation of the isolates. For serological studies the DAS-ELISA method was used, in which the pathogen was identified as pepper mild mottle tobamovirus. During the pathological examination different host-plants have been used including some pepper varieties containing different L genes (L + –L 4). It was found, that the Hungarian isolates belonged to the P 1,2 pathotype and were closely related to the Spanish isolate (PMMV-S). PCR- studies proved the presence of the PMMoV P 1,2 pathotype in Hungary as well.
Authors:A. P. Takács, G. Kazinczi, J. Horváth and R. Gáborjányi
Susceptibility of 33 Lycopersicon
species and intra-specific taxa to 6 viruses such as U/246 strain of Cucumber
mosaic virus (CMV), Pepino mosaic virus (PepMV), Potato virus X (PVX), NTN
strain of Potato virus Y (PVYNTN), Tobacco mosaic virus (TMV) and Tomato mosaic
virus (ToMV) were studied. Inoculated plants were tested for susceptibility on
the basis of symptoms, serological reactions (DAS-ELISA) and back inoculation.
All tested plants were susceptible to PepMV, PVX, TMV and ToMV. However,
Lycopersicon esculentum Mill. convar. parvibaccatum Lehm. var. cerasiforme
(Dun.) Alef.s.l., L. peruvianum (L.) Mill. and L. hirsutum Humb. et Bonpl. were
extreme resistant (immune) to PVYNTN. L. esculentum Mill. convar. infiniens
Lehm. var. flammatum Lehm., L. esculentum Mill. convar. fruticosum Lehm. var.
speciosum Lehm. and L. esculentum Mill. convar. infiniens Lehm. var. validum
Bail. showed extreme resistance to CMV-U/246. The other 30 species and
intra-specific taxa were susceptible to CMV-U/246. New compatible and
incompatible host-virus relations have been reported.
The extreme resistant Lycopersicon intra-specific taxa could be used as
resistance sources in tomato breeding.
Authors:G. Jenser, L. Bujdos, R. Gáborjányi, Asztéria Almási, Ágnes Szénási and T. Fekete
Tomato spotted wilt virus (TSWV) is spread by Thrips tabaci tabaci nominate subspecies in the field under climatic conditions of Carpathian Basin. The overwintered females harbouring the pathogen proved to be the most important vector in the outbreak of epidemics in the tobacco growing district. Among the numerous host plants, the winter annual and the perennial weeds provide the survival of the pathogen. Infected weeds as Asclepias syriaca, Convolvulus arvensis grown in vineyards far from the tobacco fields and greenhouses indicate the wide spread of TSWV. Chickweed (Stellaria media) being a suitable host both for TSWV and the overwintering T. tabaci specimens constitutes the most dangerous source of epidemics. As a result of the common effect of the application of insecticides in accordance with the monitoring of T. tabaci, the centralized cultivation of the seedlings and the weed-free surroundings of the nurseries, the occurrence of TSWV was reduced to the minimum level in tobacco fields.
Authors:E. Cseh, M. Apró, G. Bese, L. Krizbai, K. Bóka, R. Gáborjányi and A. Takács
Tomato spotted wild virus (TSWV) has become an important plant pathogen during the past 10 years in Hungary. This virus belongs to the family of Bunyaviridae, genus Tospovirus. According to the latest studies, this virus has about 1090 host plant species, including crops and weeds. In the autumn of 2009, some Aristolochia clematitis plants were collected showing symptoms of TSWV infection. On the basis of electron microscopic and molecular studies, leaf samples of Aristolochia clematitis L. found in a vineyard proved to be infected with Tomato spotted wilt virus (TSWV). This is the first report on the occurrence of TSWV in Aristolochia in Hungary.
Authors:G. Jenser, Aszteria Almási, Gabriella Kazinczi, A. Takács, Ágnes Szénási and R. Gáborjányi
Ecological background of the dissimilar ways of the spread of
tomato spotted wilt virus
(TSWV) was investigated in the fields in tobacco stands and in the greenhouses in forced green pepper and tomato cultures, under continental climatic conditions in Hungary.
Authors:Z. Áy, Z. Kerényi, A. Takács, M. Papp, I. Petróczi, R. Gáborjányi, D. Silhavy, J. Pauk and Z. Kertész
The reliable monitoring of field virus infections of crop species is important for both farmers and plant breeders. The aim of this study was to detect virus infections of winter wheat in the 2006/2007 season. Twelve well-known winter wheat varieties were sown on two different dates (11
of October and 3
of November 2006). Leaves of two individuals from each genotype were collected on 23rd of April 2007 to detect the virus infections (
Barley stripe mosaic virus
Barley yellow dwarf virus
Wheat dwarf virus
— WDV and
Wheat streak mosaic virus
— WSMV) after an extra mild autumn- and wintertime. Virus infections were detected by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). The aphid-transmitted BYDV-PAV was found frequently whereas other viruses were presented very rarely or were not detected. Forty-six per cent of the tested wheat plants proved to be infected by BYDV-PAV in ELISA, while using PCR, the virus infections with BYDV-PAV was found in 58% of the samples. Further, these results suggest that the optimal sowing time is critical in the control of cereal virus diseases, and additionally, that wheat varieties respond to the virus infections differently.