Slide 1

Looking at the unstable and cell-autonomous nature of R-gens

Cloning of AVR-genes, R-genes

Can be defined a number of ways;

All (?) Avr genes are effectors

We now know that microbial pathogens export a whole arsenal of effector molecules into their host to alter their environment for their purposes.

Hogenhout et al MPMI 2009 22:115-122 list the following functions:

Coronatine inhibits stomatal closure

Slide 9

Slide 10

Many effectors that suppress that supress HR/ programmed cell death (PCD) in plants also suppress PCD in yeast.

Slide 12

E.g.

Some effectors may have multiple targets

Slide 15

Less is known about fungal Avr genes/effectors

Slide 17

Probably the most is known about effectors from this group of plant pathogens.

Phytophthora

Hass et al 2009 Nature 461:393-398

196 CRN genes, 255 pseudogenes

Wroblewski et al Plant Phys 2009 150:1733-1749.

Slide 23

Slide 24

Reaction to effectors was frequent and often stronger in nonhost that in host species.

Slide 26

In some cases a necrotic reaction was elicited by a gene from a pathogen that was virulent on that host.

Horizontal transfer is common between closely related bacteria.

Pathogens are injecting a lot of things into the host to create an environment conducive for their growth

Slide 30

From

Slide 32

Slide 33

Unlike Avr genes , most (not all) R-genes share some structural features

Kinase- an enzyme that phosphorylates and amino acid

Class 1 Pto- Serine/Threonine Kinase

Slide 37

LRR (Leucine –rich- repeat)

Slide 39