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: 9062

#Unit 4. Cell Communication and Cell Signaling

GPK enzyme activity is increased either by phosphorylation of these two regulatory subunits by PKA or by Ca+2 binding to the calmodulin subunit; maximal activity requires both.

TLS Online TPP Program

#Id: 9063

#Unit 4. Cell Communication and Cell Signaling

Phosphorylation of PKA at threonine-197 leads to conformational change in the activation loop, that promotes binding of both ATP and its substrate proteins.

PKA can autophosphorylate itself on T197

TLS Online TPP Program

#Id: 9064

#Unit 4. Cell Communication and Cell Signaling

The activities of GPK and GP are inhibited by a phosphatase called phosphoprotein phosphatase.

TLS Online TPP Program

#Id: 9065

#Unit 4. Cell Communication and Cell Signaling

The promoter or enhancer segments of all genes regulated by PKA contain a cis-acting DNA sequence, the cAMP-response element (CRE), which

contains the highly conserved nucleotide sequence,

5'-TGACGTCA-3'.

TLS Online TPP Program

#Id: 9066

#Unit 4. Cell Communication and Cell Signaling

In nucleus PKA phosphorylate serine-133 on a transcription factor called CREbinding (CREB) protein

TLS Online TPP Program

#Id: 9067

#Unit 4. Cell Communication and Cell Signaling

Phosphorylated CREB binds to CRE-containing target genes and also binds to the co-activator termed CBP/P300, thereby stimulating gene transcription