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Date: 18 December 2010
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[Ref: A Gijon-Hernandez et al: Leaf stripe and stem rot caused by _Burkholderia gladioli_, a new maize disease in Mexico. J Phytopath 2010; DOI: 10.1111/j.1439-0434.2010.01776.x]
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A disease in maize plants, not previously observed, appeared in 2003 -
2004 in Cosoleacaque, Tlalixcoyan, and Paso de Ovejas counties, in the state of Veracruz, Mexico.
Initial symptoms on leaves were small white-yellow watery spots, which coalesced into dry necrotic stripes 0.3 cm wide and up to 8 cm long.
Reddening sometimes developed on these leaves. Stems developed a rot in the crown. The flag leaf became rotted and necrotic at the base, rolled inwards and dried out. Necrosis developed at the base of the ears and their growth was inhibited. These symptoms were initially observed in commercial maize plantings.
A bacterium characterized by white, opaque, round colonies with entire margins, gram negative, aerobic and rod-shaped was consistently isolated from diseased maize plants. The bacterium's identity was confirmed by PCR amplification and sequencing of 16S and 23S rDNA gene fragments. The bacterium was identified as _Burkholderia gladioli_.
Its pathogenicity on maize plants in Mexico is a new record.
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Communicated by:
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[_B. gladioli_ (formerly _Pseudomonas gladioli_ or _P. marginata_) was initially described in 1921 as a soil inhabiting phytopathogen of gladioli and other flowers. It causes, for example, bulb soft rot of onion; scab, soft and corm rots of gladiolus, iris, freesia, and other flower crops; soft rot of orchids with up to 50 percent loss; grain rot, panicle blight, and leaf-sheath browning of rice plants (sometimes together with other species in the genus).
The pathogen is spread in soil and water, by mechanical means (including insects), and with infected plant material. Disease management includes the use of clean planting material and cultural practices such as frequent disinfection of tools, insect control, and reduction of free moisture in plantings.
_B. gladioli_ is a heterogeneous species with phenotypic and genetic variability and has been divided into pathovars, including _gladioli_, _alliicola_ and _agaricicola_, based on their host ranges. Strains assisting in nitrogen fixation have been found in the rhizospheres of a number of cereals and sugarcane. Some strains are nematode and fungal antagonists and can be used in biocontrol (for example for _Fusarium_ species); some strains are plant growth promoters. Strains producing human toxins or associated with infections in humans have also been reported.
An ear soft rot of maize caused by _B. gladioli_ has been reported from Brazil and the USA (see ProMED-mail post 20080123.0283). No information seems to be available regarding the pathovars for either of the 2 reported diseases of maize.
Maps
Mexico:
Veracruz:
Pictures
Symptoms of _B. gladioli_:
(gladiolus),
(crown rot of lisianthus) and
_B. g._ pv. _alliicola_ slippery skin of onion:
Links
Information on _B. gladioli_:
_B. gladioli_ on rice:
_B. gladioli_ on onion:
_B. gladioli_ on orchids:
Biocontrol applications:
PCR detection and differentiation of _B. gladioli_:
_B. gladioli_ taxonomy:
Genus _Burkholderia_ taxonomy and species list:
genus=BURKHOLDERIA&show_all_details=1>
- Mod.DHA]
[see also:
2008
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Burkholderia gladioli ear rot, maize - USA: 1st rep, (MS) 20080123.0283]
Topics
Species
