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Genomic characterization using nonradioactive probes, polymerase chain reaction with degenerate primers for whitefly transmitted geminiviruses and nucleotide sequencing were used to describe a new bipartite geminivirus, associated with dwarfing and leaf curling of tomatoes and peppers in Jamaica. Partial DNA-A and DNA-B clones were obtained. DNA sequence analysis showed that tomato and pepper samples have a similar geminivirus associated with them. Nucleotide sequence identity > 92% between the common regions of DNA-A and DNA-B confirmed the bipartite nature of the Jamaican geminivirus isolates. Nucleotide sequence comparisons of DNA-A and DNA-B with those of geminiviruses representing the major phylogenetic groups of Western Hemisphere geminiviruses showed the greatest similarity to potato yellow mosaic virus and members of the Abutilon mosaic virus cluster of geminiviruses. This new virus is given the name tomato dwarf leaf curl virus (TDLCV) because of the dwarfing and leaf curling symptoms associated with infected tomato plants. Polymerase chain reaction and Southern hybridization showed mixed infections of TDLCV with tomato yellow leaf curl virus from Israel in 16% of the field samples of tomatoes and peppers. 相似文献
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Wernecke Anna Eckert Jakob H. Forster Rolf Kurlemann Nils Odemer Richard 《植物病害和植物保护杂志》2022,129(1):93-105
Journal of Plant Diseases and Protection - Currently, more than 360 spray adjuvants are registered in Germany (September 2021). Unlike plant protection products (PPPs), adjuvants are not subjected... 相似文献
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A forest ecosystem study was conducted along a deposition gradient of air pollutants in old Scots pine stands located near the industrial belt around the city of Bitterfeld in northeast Germany from 1999 to 2000. In order to estimate the impact of different atmospheric deposition loads on microbial biomass and enzyme activities, samples were taken from the forest floor (L, F, and H horizon) and the mineral topsoil (0–10 cm). The emission-induced increases in ferromagnetic susceptibility, soil pH, concentrations of mobile (NH 4NO 3 extractable) Cr and Ni, effective cation exchange capacity, and base saturation in the humus layer along the 25-km long transect reflected that great portions of the past depositions were characterized by alkaline fly ash. Alkaline depositions significantly ( P <0.05) decreased the microbial biomass C and N contents, microbial biomass C-to-organic C ratios, and microbial respiration rates, but increased the metabolic quotient (qCO 2) of the mineral topsoil and forest floor. Variations in microbial biomass and activity can mainly be predicted ( r 2 =0.60) by the concentrations of Ca, Zn and Cd in these forest soils. The specific activities (activity kg -1 organic C) of l-asparaginase, l-glutaminase, arylsulfatase, and in part, acid phosphatase were significantly ( P <0.05) higher at forest sites receiving higher fly ash loads than those of the other sites, and thus followed the trend of the qCO 2. In contrast, the specific activity of ß-glucosidase was significantly ( P <0.05) decreased at heavily affected sites compared to moderate and less affected sites, suggesting an inhibition of C mineralization in the forest floor of pine stands affected by predominantly alkaline emissions. A great portion ( r 2=0.91) of the variation in the specific enzyme activity data in forest soils in emission areas can be predicted from a linear combination of the variables total organic C and NH 4Cl-extractable Ca, pH and effective cation exchange capacity. 相似文献
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