Bacterial Plant Pathogens - Diseases and Mechanisms

Burkholderia caryophylli causes bacterial wilt. It is known to contain enzyme D-threo-aldose 1-dehydrogenase, which allows it to oxidise L-glucose.

Acidovorax citrulli infection can result in bacterial fruit blotch (BFB). Lesions are necrotic and may be located near veins. The fruit eventually decays and cracks when the pathogen causes necrosis.

Correct Answer: Bacterial panicle blight of rice

Phytoplasma antigenic protein has been shown to interact with insect microfilament complexes. It is believed to be the determining factor in insect-phytoplasma interaction.

Brenneria rubrifaciens produces a unique red pigment (rubrifacine) that has been hypothesised to play a role in pathogenesis of walnut.

In the first stages of invasion, Clavibacter michiganensis resides as a biotrophic pathogen in the xylem vessels. They multiply by binary fission inside the vessel and establish colony there. If colonisation is successful, they may plug the xylem vessels.

Dickeya dadantii contains many pectinases that are able to macerate and break down the plant cell wall material. This exposed part of the plant releases nutrients that can facilitate bacterial growth.

Bacterial wilt and bacterial tan spot are caused by Curtobacterium flaccumfaciens pv. flaccumfaciens.

Clavibacter michiganensis subsp. insidiosus causes wilting and stunting in alfalfa.

Leifsonia xyli subsp. xyli is a small, fastidious, Gram-positive and coryneform bacterium that is associated with the ratoon stunting disease, a major worldwide disease of sugarcane. Infected plants show reduced cane diameter and shortening of the inter-nodes.

Enterobacter bulb decay is a recently described storage disease of onion (Allium cepa), member of liliaceae family that is caused by Enterobacter cloacae. The disease was reported in 2011. In this disease, the exterior of the bulb remains asymptomatic while the inner scales show a brown to black discoloration and decay.

To transfer t-DNA into the plant cell, A. tumefaciens uses a type IV secretion mechanism that involves the production of a T-pilus.

Blackleg in potatoes is caused by Pectobacterium atrosepticum. It results in stunting, wilting, chlorosis of leaves, necrosis of several tissues, a decline in yield and the death of the potato plant.

Pseudomonas cichorii is a Gram-negative soil bacterium that is pathogenic to lettuce, celery and chrysanthemum crops. It produces 6-aminopenicillanic acid that forms the core of penicillin. It shows the possibility of being commercially exploited for obtaining 6-Amino penicillanic acid.

There is no known cure for fire blight. Disease can be prevented by injecting plants with oxytetracycline.