Ophiostoma novo-ulmi

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1. Classification

Higher order taxa

Eukaryota; Opisthokonta; Fungi; Dikarya; Ascomycota; saccharomyceta; Pezizomycotina; leotiomyceta; sordariomyceta; Sordariomycetes; Sordariomycetidae; Ophiostomatales; Ophiostomataceae; Ophiostoma

Species

NCBI: [1]

Ophiostoma novo-ulmi subsp. americana

	Ophiostoma novo-ulmi subsp. novo-ulmi [1].
Ophiostoma Novo-Ulmi fruiting bodies that form in galleries made by the bark beetle. Photo: Joseph OBrien, USDA Forest Service, Bugwood.org http://www.invasive.org/browse/detail.cfm?imgnum=5252020.

2. Introduction

Ophiostoma novo-ulmi is classified as an ascomycete fungus that spreads its spores by projecting them from elongated sacs (asci) into the air. Morphologically it consists of white/grey hyphae and a perithecial neck (250-640 µm in width), which encloses the asci. Also O. novo-ulmi can withstand temperatures of up to 33°C and the fungi’s optimal growth temperature is around 20-22°C [2]. In the 1960s O. novo-ulmi was found to cause Dutch Elm Disease (DED), which devastated the elm tree population throughout North America [3]. The pathogenicity of O. novo-ulmi can be attributed to the Pat1 gene, as well as metabolic products like diaporthic acid and phenolic acids, which are toxic to elm tree species [4] [5] [6. Through thorough research, the mechanisms and cellular components of O. novo-ulmi’s pathogenicity seem to be very well understood, but there is more research needed on the other processes unrelated to the pathogenicity. O. novo-ulmi can be further classified into two subspecies, americana and novo-ulmi, which have the ability to hybridize. This hybridization can create enhanced toxic mechanisms and host resistance that has the ability to hinder the establishment of new elm tree populations. This ultimately limits scientists’ ability to develop preventative mechanisms for population recovery [7]. There is little known about the specific differences between the subspecies, therefore this is an area open to further research. Dutch Elm Disease is spread by adult bark beetles, which carry the O. novo-ulmi spores. The spores eventually enter the secondary xylem of elm trees, which clogs the internal vessels of the tree and eventually causes death [8] [7]. Due to the aggressiveness of DED throughout Europe and North America, establishing proper control mechanisms has been a challenging feat [9]. Different solutions have been developed to protect elms from DED. For instance, as further described in the article, chemical treatments to eradicate the disease as well as genetic manipulation in order to target the root cause of pathogenicity were created [9] [10] [11]. Treating the trees with salicylic acid and genetically modifying them to resist the toxins of the fungus have been shown to be effective measures of combating the pathogen [10] [11]. Nevertheless, future research needs to be conducted to fully halt the spread of this disease.

3. Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?

4. Cell structure

Interesting features of cell structure. Can be combined with “metabolic processes”

5. Metabolic processes

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6. Ecology

Habitat; symbiosis; contributions to the environment.

7. Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

7. Key microorganisms

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8. Current Research

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9. References

It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.