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Date: June, 2008
Source: The American Phytopathological Society, Plant Disease 2008;
92(6): 981 [edited]
<http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-92-6-0981A>

[Ref: K Trzmiel, M Jezewska: Identification of _Maize dwarf mosaic virus_ in Maize in Poland. Plant Dis 2008; 92(6): 981; DOI: 10.1094/PDIS-92-6-0981A]

From 2005 to 2007 in Southern Wielkopolska, Lower Silesia, and Malopolska regions, maize (_Zea mays_) plants showing leaf mosaic and stunting symptoms were found. ELISA (enzyme-linked immunosorbent assay) tests using commercial polyclonal antisera against _Maize dwarf mosaic virus_ (MDMV) gave positive results in 71 samples.
However, the ELISA response for symptomatic plants, in most cases, was low. Therefore, only 8 plants with relatively high virus concentration were chosen for further identification assays.

Examination of leaf extracts with an electron microscope revealed the presence of potyvirus-like particles. Symptomatic leaves were positive for MDMV by using immunosorbent electron microscopy (ISEM) with antiserum raised against the Spanish isolate of MDMV used as positive control. A set of test plants, including sweet corn, dent corn, sorghum (_Sorghum vulgare_), and true millet (_Panicum miliaceum_), were mechanically inoculated with extracts from symptomatic plants. Inoculated plants developed symptoms typical of MDMV in 2 to 5 weeks.

For further investigations, 3 virus isolates were chosen. To confirm the identification of MDMV, reverse transcription (RT)-PCR (polymerase chain reaction) was performed with total RNA isolated from infected plants. The RT-PCR products obtained were analyzed by agarose gel electrophoresis. Amplicons of the expected sizes (635 and 560 bp) were obtained with RNA from symptomatic plants, but not from asymptomatic plants. The highest nucleotide sequence identities were 99 percent with 3 Spanish MDMV isolates, 91 percent with the Hungarian isolate "Sc/H, sweet corn", 90 percent with "MDMV-A" U07216, and 87 percent with an Israeli MDMV. On the basis of these findings, the virus isolated from diseased maize plants was identified as MDMV. The significance of MDMV detection is noteworthy because maize has become an important crop in Poland in recent years and acreage is increasing systematically.

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[_Maize dwarf mosaic virus_ (MDMV, genus _Potyvirus_) affects maize, sorghum, millets, and several grass species. Symptoms may vary according to hosts and environmental conditions, but generally include leaf mosaic or streaks, leaf discolourations, stunting of plants, excessive tillering, and low seed set. In maize, early infection can lead to root and stalk rots and plant death. Infection sites in the field are often sporadic and may be individual plants, clusters, or rows along the edge of the field (often close to grasses serving as virus reservoirs). Several strains of MDMV exist denoted as A to F and possibly additional ones. The virus is spread by several species of aphid vectors in a non-persistent manner and may also be transmitted by mechanical means and seed. MDMV survives between seasons in rhizomes of some host species. Disease management includes use of resistant crop varieties and control of virus reservoirs.

Maps
Poland:
<http://graphicmaps.com/webimage/countrys/europe/lgcolor/plcolor.htm>
and <http://healthmap.org/promed?v=52.1,19.4,5>
Provinces of Poland:
<http://www.lib.utexas.edu/maps/europe/poland_pol00.jpg>

Pictures
MDMV leaf symptoms:
<http://hgic.clemson.edu/factsheets/Graphics/corndis/mdmv.jpg>  and <http://plantpathology.tamu.edu/Texlab/Grains/Corn/Images/corn15.jpeg>
MDMV affected maize plant:
<http://www.gaipm.org/id/assets/images/21-2.jpg>  and <http://plantpathology.tamu.edu/Texlab/Grains/Corn/Images/corn15.jpeg>
_Potyvirus_ particles, electron micrograph:
<http://www.ncbi.nlm.nih.gov/ICTVdb/WIntkey/Images/a1.gif>

Links
MDMV disease information:
<http://nu-distance.unl.edu/Homer/disease/agron/corn/CoMDMV.html>  and <http://vegetablemdonline.ppath.cornell.edu/factsheets/Virus_SweetCorn.htm>
MDMV taxonomy and description:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.057.0.01.039.htm>.  - Mod.DHA]

[see also in the archive:
2004
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Regulated plant pests, detection, September 2004: EPPO 20041110.3037]
 

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