Xanthomonas vasicola pv. vasculorum (Xvv) is a gram-negative rod-shaped bacterium which has a single polar flagellum. It is a plant pathogen, causing both bacterial leaf streak of maize (corn) and sugarcane gumming disease. One outbreak in eucalyptus has been reported.[1] Under experimental conditions it can infect sorghum, oats and some grass species. It is not currently a quarantine pathogen in any country, but it has already spread outside its native range and is highly adaptable to different environments.[2]

Xanthomonas vasicola
Typical symptoms of bacterial leaf streak on maize leaf caused by Xanthomonas vasicola pv. vasculorum
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Pseudomonadota
Class: Gammaproteobacteria
Order: Xanthomonadales
Family: Xanthomonadaceae
Genus: Xanthomonas
Species:
X. vasicola
Binomial name
Xanthomonas vasicola
Cobb 1894

The means of dispersal are not yet confirmed. Similar Xanthomonas pathogens are spread via wind-blown water droplets, irrigation, agricultural machinery and movement of infected plants. There are no known insect vectors.[3]

Like other members of the Xanthomonas genus, it forms yellow colonies when grown on agar and secretes abundant xanthan exopolysaccharides.[3]

Bacterial leaf streak of maize edit

Leaf streak of maize was first observed in South Africa in 1949. The disease was then observed in Argentina in 2010 and the USA in 2014. It is now widespread in the USA as well as being found in Brazil, Argentina, Madagascar, South Africa and Zimbabwe.[3]

X. vasicola pv. vasculorum enters maize leaves through the stomata and colonises the intercellular spaces. Visible symptoms are long thin lesions that run parallel to the leaf vein and have wavy or jagged margins. Lesions can be yellow, orange or brown and expand over time. When held up to the sun lesions appear translucent with a yellow halo. In humid conditions polysaccharide ooze may be seen on leaves. It can be diagnosed via microscopy and culturing, or PCR.[4]



Sugarcane gumming disease edit

Sugarcane gumming disease was first reported in Puerto Rico the 1920s.[5]  As with corn, long thin leaf lesions are seen. They may be orange, yellow, brown, grey or white depending on the stage of infection.  As the disease progresses the bacteria spreads to the stem via the vascular system. Secretion of exopolysaccharides leads to gumming and vascular ooze which blocks the flow of water and nutrients through the plant. This leads to wilting and if the stem is cut a thick ooze emerges.[6]

References edit

  1. ^ Coutinho, T. A.; van der Westhuizen, L.; Roux, J.; McFarlane, S. A.; Venter, S. N. (June 2015). "Significant host jump of Xanthomonas vasicola from sugarcane to a Eucalyptus grandis clone in South Africa". Plant Pathology. 64 (3): 576–581. doi:10.1111/ppa.12298. ISSN 0032-0862.
  2. ^ Ortiz-Castro, Mary; Hartman, Terra; Coutinho, Teresa; Lang, Jillian M.; Korus, Kevin; Leach, Jan E.; Jackson-Ziems, Tamra; Broders, Kirk (June 2020). "Current Understanding of the History, Global Spread, Ecology, Evolution, and Management of the Corn Bacterial Leaf Streak Pathogen, Xanthomonas vasicola pv. vasculorum". Phytopathology. 110 (6): 1124–1131. doi:10.1094/PHYTO-01-20-0018-PER. ISSN 0031-949X. PMID 32271651. S2CID 215727636.
  3. ^ a b c Triplett, L; Patel, R (2022-01-07). Xanthomonas vasicola pv. vasculorum (bacterial leaf streak of corn) (Report). doi:10.1079/cabicompendium.36777909.
  4. ^ "Bacterial leaf streak (Xanthomonas vasicola vasculorum) | Integrated Crop Management". crops.extension.iastate.edu. Retrieved 2023-11-23.
  5. ^ Cook, Melville T. (1928-07-01). "Título en español". The Journal of Agriculture of the University of Puerto Rico (in Spanish). 12 (3): 143–179. doi:10.46429/jaupr.v12i3.14056. ISSN 2308-1759. S2CID 135362532.
  6. ^ Wasukira, Arthur; Coulter, Max; Al-Sowayeh, Noorah; Thwaites, Richard; Paszkiewicz, Konrad; Kubiriba, Jerome; Smith, Julian; Grant, Murray; Studholme, David J. (March 2014). "Genome Sequencing of Xanthomonas vasicola Pathovar vasculorum Reveals Variation in Plasmids and Genes Encoding Lipopolysaccharide Synthesis, Type-IV Pilus and Type-III Secretion Effectors". Pathogens. 3 (1): 211–237. doi:10.3390/pathogens3010211. ISSN 2076-0817. PMC 4235730. PMID 25437615.

External links edit