Query: NC_010577:530917 Xylella fastidiosa M23, complete genome
Lineage: Xylella fastidiosa; Xylella; Xanthomonadaceae; Xanthomonadales; Proteobacteria; Bacteria
General Information: This strain was isolated from an almond tree in California. Causal agent of citrus variegated chlorosis. This organism was first identified in 1993 as the causal agent of citrus variegated chlorosis, a disease that affects varieties of sweet oranges. Other strains of this species cause a range of diseases in mulberry, pear, almond, elm, sycamore, oak, maple, pecan and coffee which collectively result in multimillion dollar devastation of economically important plants. It does not contain a type III secretion system, but possesses genes for a type II secretion system for export of exoenzymes that degrade the plant cell wall and allow the bacterium to colonize the plant xylem. The cell produces an exopolysaccharide that is similar to the xanthan gum produced by Xanthomonas campestris pv. campestris.
Subject: NC_002971:951102 Coxiella burnetii RSA 493, complete genome
Lineage: Coxiella burnetii; Coxiella; Coxiellaceae; Legionellales; Proteobacteria; Bacteria
General Information: Causes Q-fever. This organism is widely distributed in nature and can cause infections in reptiles, birds, and mammals. It causes Q fever, or 'query' fever, an atypical pneumonia first associated with abattoir workers in Australia. Transmission may be through insect vectors such as ticks that have bitten an infected wild or domesticated animal, or through an aerosol produced by domesticated animals such as sheep or cattle. The presence of a plasmid is believed to be associated with virulence and pathogenicity, however C. burnetii isolates containing plasmid QpDG are avirulent in guinea pigs and plasmidless isolates have been associated with endocarditis in humans. Coxiella burnetii has a developmental life cycle, and can grow vegetatively through binary fission, or asymmetrically and produce a spore-like cell. The spore-like cell may enable the organism to exist extracellularly for small amounts of time. This bacterium is an obligate intracellular pathogen. It is endocytosed by a host cell, a macrophage for example, and lives and replicates inside the phagolysozome, a unique property of this organism. The genome encodes proteins that have a higher than average pI, which may enable adaptation to the acidic environment of the phagolysozome. The chromosome also contains genes for a number of detoxification and stress response proteins such as dismutases that allow growth in the oxidative environment. The type IV system is similar to the one found in Legionella, which may be important for intracellular survival. This organism produces numerous ankyrin-repeat proteins that may be involved in interactions with the host cell. The genome has 83 pseudogenes, which may be a result of the typical genome-wide degradation observed with other intracellular organisms and also has a group I intron in the 23S ribosomal RNA gene.