They are also known to activate WRKY type transcription factors that are involved in transcriptional next activation of disease resistance genes. Indeed, we have observed a modest, but elevated expression of four genes belonging to the WRKY family and disease resist ance protein. We also observed increased transcript abundance for sev eral genes involved in plant growth and development. For example, expansins were detected as highly induced transcripts in ABR17 transgenic A. thaliana. Expansins are cell wall proteins that are known to induce pH dependent plant cell wall extension and stress relaxation. The expansins have been related to cell differentiation in tissues such as xylem, leaf primordia and root hairs. Previous studies on transgenic plants expressing expansin genes have demonstrated pre cocious leaf development, longer petioles and larger leaf blades.
Glycine rich proteins were also detected among growth related genes that whose transcripts increased in abundance Inhibitors,Modulators,Libraries in ABR17 transgenic plants. GRPs consist of quasi repetitive glycine rich domains, most commonly GGGX, GGXXXGG or GXGX repeats. Some GRPs have been reported as structural Inhibitors,Modulators,Libraries components of the plant cell walls based on their co localization with cell wall. GRPs have also been reported to be acti vated by osmotic stress, cold shock and wound ing. The genes that exhibited significant enhanced expression in ABR17 transgenic plants also included genes for pro line rich protein family, xyloglucon endotransglyc osylase, glycosyl hydrolase, phytosulfokine precursor 2, No Apical Meristem protein family and glutaredoxins.
PRPs repre sent a family of structural cell wall proteins that have been implicated in various plant developmental processes. Similarly, XTH and GH family Inhibitors,Modulators,Libraries genes are involved in structuring xyloglucan cross links in plant cell wall and plant development and. The PSK2 gene is also involved Inhibitors,Modulators,Libraries in cell growth and differentiation. Similarly, the NAM gene product is required for shoot api cal meristem formation during embryogenesis as well as for normal flower development. Glutare doxins have also been demonstrated to be involved in flower development, probably by mediating post transla tional modifications of target proteins required for nor mal petal organ initiation Inhibitors,Modulators,Libraries and morphogenesis.
Our current observations that the significantly higher expression of the above mentioned selleck chemical Calcitriol genes related to growth and development including flowering correlates well with the observed phenotypes which include early flowering, increased lateral branching and seed pods as observed in ABR17 transgenic A. thaliana. A role for cytokinins in ABR17 induced changes in gene expression Interestingly, members of most of the gene families described above that are involved in plant defense as well as growth and development, have been previously reported to be regulated by CKs.