Cytokinins control cell differentiation via regulation of secondary cell wall master switches NST1 and NST3
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| Year of publication | 2016 |
| Type | Appeared in Conference without Proceedings |
| MU Faculty or unit | |
| Citation | |
| Description | Plant hormones cytokinins were shown to control the equilibrium between cell division and cell differentiation, the process of key developmental importance across all kingdoms. However, the underlying molecular mechanism is mostly unknown. Here we present the role of cytokinins in the control of differentiation program in secondary cell wall (SCW) containing cells. We found that impaired cytokinin signaling disturbs apical/basal developmental gradient in the inflorescence stem of Arabidopsis thaliana. Attenuating cytokinin signaling results in precocious differentiation of SCW containing cells (vessels and fibers), higher lignin and sugars content and formation of vessels with reduced diameter and impaired water conductance. The next-gen transcriptional profiling of cytokinin signaling mutants revealed ectopic upregulation of NST1 and NST3, the NAC transcription factors and master switches of SCW formation and the regulators and effector proteins of the downstream transcriptional cascade. The negative role of cytokinins in the control over SCW formation via inhibiting NSTs expression was confirmed using exogenous cytokinin application in pNST3:NST3-GUS line and via genetic manipulation of endogenous cytokinin content in the cytokinin biosynthetic mutant atipt1,3,5,7. Importantly, exogenous cytokinin application reversed not only the early SCW formation phenotype of atipt1,3,5,7 plants, but also recovered the WT expression gradient of the entire SCW developmental pathway. Based on our findings we propose the role of cytokinins as a positional cue controlling cell differentiation status via regulating expression of SCW master switches NST1 and NST3. |
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