Rapid termination mechanisms of the Rhodopsin Signalling:

1.GAP that inactivates Gαt·GTP

2.Ca2+ -sensing proteins that activate Guanylate Cyclase

3.Rhodopsin Phosphorylation and Binding of Arrestin

TLS Online TPP Program

#Id: 9782

#XL - R Botany

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

TLS Online TPP Program

#Id: 9783

#XL - R Botany

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

#XL - R Botany

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

#XL - R Botany

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.

TLS Online TPP Program

#Id: 9786

#XL - R Botany

Tomato Cf genes is also encodes a R proteins that recognize apoplastic effectors are receptor‐like proteins (RLPs) against the extracellular colonizing fungus Cladosporium fulvum for Avr9

TLS Online TPP Program

#Id: 9787

#XL - R Botany

Lr34 of wheat, maize Rp1 locus, Xa21 in rice and tomato Pto gene are R genes