The maximum absorption of UV by DNA is at a wavelength of 254 nm. Maximum mutagenicity also occurs at 254 nm. 

TLS Online TPP Program

#Id: 10215

#Unit 6. System Physiology – Plant

F-box proteins called KISS ME DEADLY (KMD) proteins

negatively regulates the cytokinin response by targeting type-B ARR proteins for degradation via the E3 ubiquitin ligase complex, SCF-KMD

TLS Online TPP Program

#Id: 10216

#Unit 6. System Physiology – Plant

ABI4 transcription factor is cross talk factor between ABA and cytokinin

TLS Online TPP Program

#Id: 10217

#Unit 6. System Physiology – Plant

Auxin and cytokinin are both required for the initiation of xylogenesis

TLS Online TPP Program

#Id: 10218

#Unit 6. System Physiology – Plant

KNOX transcription factors activate the cytokinin biosynthetic gene ISOPENTENYL TRANSFERASE7 -IPT7

TLS Online TPP Program

#Id: 10219

#Unit 6. System Physiology – Plant

The isopentenyltransferase gene (IPT) that encodes a rate limiting enzyme in cytokinin biosynthesis, under the control of a water-deficit responsive and maturation specific promoter PSARK was introduced into cotton and the performance of the PSARK::IPT transgenic cotton plants was analyzed in the greenhouse and growth chamber conditions. 

The data indicate that PSARK::IPT-transgenic cotton plants displayed delayed senescence under water deficit conditions in the greenhouse. 

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.