There are five common subunits in all three RNA Polymerases

Rpb5

Rpb6

Rpb8

Rpb10

Rpb12

TLS Online TPP Program

#Id: 9483

#Unit 6. System Physiology – Plant

Late blight disease (A), caused by the oomycete pathogen Phytophthora infestans

Black stem rust, which results from infection by the basidiomycete Puccinia graminis

Global banana (Musa spp.) production is under threat from black Sigatoka disease Mycosphaerella fijiensis.

TLS Online TPP Program

#Id: 9484

#Unit 6. System Physiology – Plant

An effector molecule is

made by a pathogen to enhance the pathogen’s colonizing

abilities.

TLS Online TPP Program

#Id: 9485

#Unit 6. System Physiology – Plant

Plant pathogens are divided into three groups

Biotrophs derive energy from living cells, they are found on or in living plants, can have very complex nutrient requirements and do not kill host plants rapidly;

Necrotrophs derive energy from killed cells; they invade and kill plant tissue rapidly and then live saprotrophically on the dead remains;

TLS Online TPP Program

#Id: 9486

#Unit 6. System Physiology – Plant

Hemibiotrophs have an initial period of biotrophy followed by necrotrophy.

TLS Online TPP Program

#Id: 9487

#Unit 6. System Physiology – Plant

Biotrophs are Specialised (‘obligate’) pathogens

Possess appressoria or haustoria

Narrow host range

Controlled by salicylate-dependent host-defence pathways

TLS Online TPP Program

#Id: 9488

#Unit 6. System Physiology – Plant