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[1] Roles of a stolbur phytoplasma and Reptalus panzeri in the epidemiology of maize redness in Serbia
[2] Corn with symptoms of reddening: new host of stolbur phytoplasma

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[1] Roles of a stolbur phytoplasma and Reptalus panzeri in the epidemiology of maize redness in Serbia
Date: Thu 10 May 2007
Source: The British Society for Plant Pathology Blog [edited]
<http://bsppblog.blogspot.com/2007/05/going-red-in-serbia.html>

Maize redness (MR), a disease causing midrib, leaf and stalk reddening, and abnormal ear development in maize, has been reported from Serbia, Romania, and Bulgaria for 50 years. Recent epiphytotics reduced yields by 40-90 per cent in southern Banat, Serbia. Previously, it was suggested that MR symptoms were caused by _Fusarium_ spp. or fastidious bacteria; however, recently Duduk and Bertaccini reported the detection in symptomatic maize plants of a stolbur phytoplasma (subgroup 16SrXII-A, _Candidatus_ Phytoplasma solani) with the highest sequence similarity to a stolbur phytoplasma from Serbian pepper (_Capsicum annum_).

Although the epidemiology of MR is still unknown, maize hybrids showed differential sensitivity to MR and insecticide-treated plots had reduced MR incidence. Diseased fields in southern Banat were surveyed for potential
vectors of the phytoplasma during 2005 and 2006, and high populations of _Reptalus panzeri_ (_Cixiinae_, _Auchenorrhyncha_) were found. In affected fields, 20 per cent of the _R. panzeri_ individuals and 85 percent of
symptomatic maize plants carried the stolbur phytoplasma. When stolbur phytoplasma-infected _R. panzeri_ were introduced into insect-free mesh cages containing healthy maize plants, midrib and leaf reddening developed
on 48 per cent of plants and the stolbur phytoplasma was detected in 90 per cent of the symptomatic plants. No symptoms or phytoplasma-positive plants were found in cages without insects. These data indicate that MR symptoms are associated with the stolbur phytoplasma. _R. panzeri_ is both abundant in affected fields and can transmit the stolbur phytoplasma, indicating the insect is likely to be a major vector of MR.

Reference
J Jovic, et al. Roles of stolbur phytoplasma and _Reptalus panzeri_ (Cixiinae, Auchenorrhyncha) in the epidemiology of Maize redness in Serbia.
2007, Eur J Plant Pathol 118: 85-9. Available at <http://www.jic.ac.uk/staff/saskia-hogenhout/PDFs/Jovic2007.pdf>

[byline: blog by Eric Boa, Global Plant Clinic, <e.boa@cabi.org>]

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[2] Corn with symptoms of reddening: new host of stolbur phytoplasma
Date: Thu 7 Jun 2007
Source: Plant Disease, October 2006 90(10), 1313-9 [edited]
<http://www.apsnet.org/pd/+toc/2006/doc06tp.asp>

Recurrent epiphytotic outbreaks of a disease of uncertain etiology known as reddening of corn (_Zea mays_) have occurred in some areas of Serbia during the last 50 years. Affected plants show early and abnormal ripening, dry
precociously, and have poor, shriveled grains. Using molecular tools, phytoplasmas were detected in diseased plants and their identity was subsequently deduced as a subgroup 16SrXII-A strain by a variety of supporting assays involving restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR)-amplified 16S rDNA and tuf gene sequences, selective amplification of phytoplasma DNA using primer pair G35p/m, similarity of 16-23S intergenic spacer region (SR) sequences, and similarity and phylogenetic analysis of 16S rDNA gene sequences. Presence of stolbur phytoplasmas in corn with reddening symptoms is a new finding
not only for Serbia: it is the 1st report of stolbur phytoplasma in this species worldwide.

[byline: B Duduk, A Bertaccini]

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[Phytoplasmas are intracellular bacterial plant pathogens belonging to the group of mycoplasma-like organisms (MLOs). They lack a cell wall and, so far, cannot be cultured in vitro.

Phytoplasmas can be transmitted by phloem-feeding insects and by grafting. Methods used in disease management include vector control, use of clean planting material, and resistant varieties. While phytoplasma taxonomy is still being developed, stolbur phytoplasmas form a group related to _Candidatus_ Phytoplasma solani, the potato stolbur phytoplasma. Stolbur phytoplasmas have been reported from Europe and parts of Asia and Africa. Members of this group affect a range of important crops including tomato, capsicum, eggplant, strawberry, and grapevine (Bois noir, a disease causing serious damage in central European vineyards). However, hardly any species of monocotyledons have been recorded as hosts making this report an even more important finding.

Distribution map of stolbur phytoplasma
<http://www.eppo.org/QUARANTINE/bacteria/Stolbur/PHYP10_map.htm>
Map of Serbia and neighbouring countries
<http://www.commondreams.org/kosovo/kosovoimages/bceurope1.jpg>
Pictures
Maize redness symptoms:
<http://bp3.blogger.com/_jsDi86zSP9Q/RkOc6a_hNPI/AAAAAAAAAF0/c2fygXHnBns/s1600-h/MR+good+plant+IT.jpg> 

Symptoms of Stolbur phytoplasma on tomato and potato:
<http://www.eppo.org/QUARANTINE/bacteria/Stolbur/PHYP10_images.htm>
Symptoms on tomato flowers:
<http://www.apsnet.org/mpmi/covers/2006/mja06cvr.htm>
Stolbur phytoplasma symptoms on grapevine:
<http://www.bspp.org.uk/ndr/jan2005/2004-60-1.jpg>
Electron micrograph of phytoplasmas:
<http://www.international.inra.fr/var/inra_international/storage/htmlarea/427/tubescribles_webi.jpg> 

Links:
Information on potato stolbur phytoplasma:
<http://www.eppo.org/QUARANTINE/bacteria/Stolbur/PHYP10_ds.pdf>
Stolbur phytoplasma genome survey:
<http://aem.asm.org/cgi/content/full/72/5/3274>
Phytoplasma taxonomy:
<http://www.sipav.org/main/jpp/jol/jol_dec_05.htm>
Phytoplasma resource centre, information and pictures:
<http://www.ba.ars.usda.gov/data/mppl/phytoplasma.html>
_Auchenorrhyncha_ website:
<http://www.ricecrc.org/Hort/ascu/tymbal/publicat.htm>
The British Society for Plant Pathology:
<http://www.bspp.org.uk/>
Global Plant Clinic:
<http://www.globalplantclinic.org>.  - Mod.DHA]

[see also in the archive:
Zebra chip disease, potato - USA: research 20070530.1751
2006
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Bois noir phytoplasma, grapevine - Canada (BC): 1st report 20061209.3473
Phytoplasma, new, potato - USA: 1st report 20060223.0585
2004
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Stolbur phytoplasma, grapevines - Ukraine: 1st report 20041123.3134
Stolbur phytoplasma, potato - Austria: 1st report 20040628.1727
2002
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Bois noir phytoplasma, grapevine - Switzerland 20020712.4739
Bois Noir phytoplasma, grapevine - Lebanon 20020711.4723
2001
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Potato stolbur phytoplasma, potato - Austria 20011124.2877
2000
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Potato stolbur phytoplasma - Poland: EPPO report 20001127.2063
1999
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Grapevine bois noir epidemiology - France 19990718.1212]

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