Rap1 recruits Sir4 on acetylated histones, then recruits both its binding partner Sir3 and the HDAC Sir2. 

Sir3 and Sir4 then interact directly with histones H3 and H4. Once Sir3 and Sir4 have bound to histones H3 and H4, 

Sir2 deacetylates histones

Sir2-dependent deacetylation represses transcription.

TLS Online TPP Program

#Id: 10220

#Unit 6. System Physiology – Plant

PSARK::IPT transgenic cotton plants produced more root and shoot biomass, dropped fewer flowers, maintained higher chlorophyll content, and higher photosynthetic rates under reduced irrigation conditions in comparison to wild-type and segregated non-transgenic lines. 

Furthermore, PSARK::IPT-transgenic cotton plants grown in growth chamber condition also displayed greater drought tolerance. 

These results indicate that water-deficit induced expression of an isopentenyltransferase gene in cotton could significantly improve drought tolerance.

TLS Online TPP Program

#Id: 10221

#Unit 6. System Physiology – Plant

KNOX gene expression increases cytokinin levels in the shoot apical meristem by upregulating the cytokinin biosynthetic gene ISOPENTENYL TRANSFERASE7 (IPT7)

TLS Online TPP Program

#Id: 10222

#Unit 6. System Physiology – Plant

Cytokinin maintains meristem by controlling cell division

 Deficient mutants – lonely guy (LOG)/STM

 Gene activates cytokinins

TLS Online TPP Program

#Id: 10223

#Unit 6. System Physiology – Plant

Organo-genesis

TLS Online TPP Program

#Id: 10224

#Unit 6. System Physiology – Plant

BR biosynthetic pathway is a triterpenoid pathway. Mevalonic acid serves as a precursor of the triterpenoid pathway . Brassinosteroids are synthesized from the plant sterol campesterol

TLS Online TPP Program

#Id: 10225

#Unit 6. System Physiology – Plant

Members of the cytochrome P450 monooxygenase (CYP) enzyme family that are associated with the ER catalyze most of the reactions in the brassinosteroid biosynthesis pathway