Adenine is deaminated to hypoxanthine.

TLS Online TPP Program

#Id: 10137

#Unit 6. System Physiology – Plant

5 Genes involved in auxin-regulated growth and development:

1. The AUX/IAA gene family

2. The SAUR gene family

3. The GH3 gene family

Stress response genes:

1. Genes encoding glutathione S-transferases

2. Genes encoding 1-aminocyclopropane-1-carboxylic

acid (ACC) synthase

TLS Online TPP Program

#Id: 10138

#Unit 6. System Physiology – Plant

In the absence of IAA, the Transcription factor, ARF, forms Inactive heterodimers with AUX/IAA proteins.

TLS Online TPP Program

#Id: 10139

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 10140

#Unit 6. System Physiology – Plant

The auxin receptor is composed of two proteins: the SCF complex component TIR1 and the repressor protein AUX/IAA.

TLS Online TPP Program

#Id: 10141

#Unit 6. System Physiology – Plant

TIR1 recruits AUX/ IAA proteins to the SCF -TIR1 complex in an auxin-dependent manner. Once recruited by auxin, AUX/IAA proteins are ubiquitinated by the E3 ligase activity of the SCF-TIR1 complex, which marks the protein for destruction by the 26S proteasome.

TLS Online TPP Program

#Id: 10142

#Unit 6. System Physiology – Plant

PHYSIOLOGICAL EFFECTS OF AUXIN:

Three main guidance systems control the orientation of plant growth:

1. Phototropism, 

2. Gravitropism, 

3. Thigmotropism