Three major classes of animal-cell junctions: 

1. Anchoring junctions

2. Tight junctions

3. Gap junctions

TLS Online TPP Program

#Id: 9780

#Unit 6. System Physiology – Plant

LRR motif also found in the extracellular domain of several P/MAMP

TLS Online TPP Program

#Id: 9781

#Unit 6. System Physiology – Plant

R gene products are also called as NBS–LRR

TLS Online TPP Program

#Id: 9782

#Unit 6. System Physiology – Plant

According to the guard hypothesis, R gene products “guard” cellular proteins, which are called guardees or decoys

TLS Online TPP Program

#Id: 9783

#Unit 6. System Physiology – Plant

Guard hypothesis says that the Interaction between the guardees and the pathogen effectors is required for successful infection by the pathogen.

TLS Online TPP Program

#Id: 9784

#Unit 6. System Physiology – Plant

The NBS–LRR receptor remains inactive when bound to the guardee. However, when the effector interacts with the guardee, the NBS– LRR receptor becomes activated, triggering a signaling cascade that leads to the defense response.

TLS Online TPP Program

#Id: 9785

#Unit 6. System Physiology – Plant

R gene Mi-1 confers resistance to aphids and whiteflies

Rice R gene Bph14 confers resistance to the brown plant hopper

Melon R gene Vat confers resistance to the cotton aphid. 

All of these R genes encode NBS–LRR receptors.