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Friday Seminar by Ms. Sanchi Bhimrajka


SK Lab/ Friday/ May 17, 2019/ 3.30 pm/ Type B ARRs mediated hormone cross-regulation in specification of stem cell niche.
Category: Research
Posted by: bedineel

 

 

Type B ARRs mediated hormone cross-regulation in specification of stem cell niche

A new regulator in an old pathway

 

Sanchi Bhimrajka

 

Stem cells in plants are a group of undifferentiated cells which function as the source for differentiating into new tissues and/or organs. Regular maintenance of the mass of these stem cells is required to escape loss of cells or excessive proliferation due to which they are under strict regulation of external stimuli. Auxin and cytokinin play essential roles in this whole process and form complex interaction networks which are inter-connected via numerous players. It has already been well established that WUSCHEL gene represses the type-A response regulators and activates CLAVATA genes which in turn represses WUS activity which results in reduction of the stem cell size and ultimately reduction in the CLV3 gene expression. The repression of type A ARRs, the negative regulators of cytokinin, would result in enhancement of cytokinin signalling; establishing that cytokinin are required for the functioning of this negative feedback loop mechanism. In the shoot apical meristem, type-A ARRs are induced by cytokinin and repressed by auxins, which exhibit how extrinsic regulation mechanisms are developed to maintain a balance between hormones and activity of WUS and CLV3. However, the component causing the activation of WUS have largely been speculated to be cytokinin directly or indirectly. I would be talking about the recently found roles of type B ARRs in this well-established interaction network, where they work by directly binding to the promoter regions of the major characters of this pathway and help to maintain the shoot apical meristem maintenance.