In Escherichia coli, MutS scans the DNA, recognizing mismatches from the distortion they cause in the DNA backbone. 

MutS has an ATPase activity that is required for mismatch repair and recruits MutL, a second protein component of the repair system. MutL, in turn, activates MutH, an enzyme that causes an incision or nick on one strand near the site of the mismatch. Nicking is followed by the action of a specific helicase (UvrD) helicase unwinds the DNA, starting from the incision and moving in the direction of the site of the mismatch, and the filled in by DNA polymerase III

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.

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