scholarly journals Bootstrapping and Pinning down the Root Meristem; the Auxin–PLT–ARR Network Unites Robustness and Sensitivity in Meristem Growth Control

2021 ◽  
Vol 22 (9) ◽  
pp. 4731
Author(s):  
Jacob P. Rutten ◽  
Kirsten H. Ten Tusscher

After germination, the meristem of the embryonic plant root becomes activated, expands in size and subsequently stabilizes to support post-embryonic root growth. The plant hormones auxin and cytokinin, together with master transcription factors of the PLETHORA (PLT) family have been shown to form a regulatory network that governs the patterning of this root meristem. Still, which functional constraints contributed to shaping the dynamics and architecture of this network, has largely remained unanswered. Using a combination of modeling approaches we reveal how the interplay between auxin and PLTs enables meristem activation in response to above-threshold stimulation, while its embedding in a PIN-mediated auxin reflux loop ensures localized PLT transcription and thereby, a finite meristem size. We furthermore demonstrate how this constrained PLT transcriptional domain enables independent control of meristem size and division rates, further supporting a division of labor between auxin and PLT. We subsequently reveal how the weaker auxin antagonism of the earlier active Arabidopsis response regulator 12 (ARR12) may arise from the absence of a DELLA protein interaction domain. Our model indicates that this reduced strength is essential to prevent collapse in the early stages of meristem expansion while at later stages the enhanced strength of Arabidopsis response regulator 1 (ARR1) is required for sufficient meristem size control. Summarizing, our work indicates that functional constraints significantly contribute to shaping the auxin–cytokinin–PLT regulatory network.

2013 ◽  
Vol 8 (6) ◽  
pp. e24226 ◽  
Author(s):  
Yuancheng Peng ◽  
Liangliang Chen ◽  
Yaru Lu ◽  
Wenying Ma ◽  
Yiping Tong ◽  
...  

2020 ◽  
Vol 64 (4-5-6) ◽  
pp. 299-318
Author(s):  
Carmen M.A. Coelho

The regulation of growth and the determination of organ-size in animals is an area of research that has received much attention during the past two and a half decades. Classic regeneration and cell-competition studies performed during the last century suggested that for size to be determined, organ-size is sensed and this sense of size feeds back into the growth control mechanism such that growth stops at the “correct” size. Recent work using Drosophila imaginal discs as a system has provided a particularly detailed cellular and molecular understanding of growth. Yet, a clear mechanistic basis for size-sensing has not emerged. I re-examine these studies from a different perspective and ask whether there is scope for alternate modes of size control in which size does not need to be sensed.


1999 ◽  
Vol 39 (supplement) ◽  
pp. S100
Author(s):  
S. Suzuki ◽  
T. Maruta ◽  
Y. Nakamura
Keyword(s):  

2021 ◽  
Vol 118 (11) ◽  
pp. e2004384118
Author(s):  
Xiaojian Xia ◽  
Han Dong ◽  
Yanling Yin ◽  
Xuewei Song ◽  
Xiaohua Gu ◽  
...  

The control of apical dominance involves auxin, strigolactones (SLs), cytokinins (CKs), and sugars, but the mechanistic controls of this regulatory network are not fully understood. Here, we show that brassinosteroid (BR) promotes bud outgrowth in tomato through the direct transcriptional regulation of BRANCHED1 (BRC1) by the BR signaling component BRASSINAZOLE-RESISTANT1 (BZR1). Attenuated responses to the removal of the apical bud, the inhibition of auxin, SLs or gibberellin synthesis, or treatment with CK and sucrose, were observed in bud outgrowth and the levels of BRC1 transcripts in the BR-deficient or bzr1 mutants. Furthermore, the accumulation of BR and the dephosphorylated form of BZR1 were increased by apical bud removal, inhibition of auxin, and SLs synthesis or treatment with CK and sucrose. These responses were decreased in the DELLA-deficient mutant. In addition, CK accumulation was inhibited by auxin and SLs, and decreased in the DELLA-deficient mutant, but it was increased in response to sucrose treatment. CK promoted BR synthesis in axillary buds through the action of the type-B response regulator, RR10. Our results demonstrate that BR signaling integrates multiple pathways that control shoot branching. Local BR signaling in axillary buds is therefore a potential target for shaping plant architecture.


2018 ◽  
Vol 110 (5) ◽  
pp. 741-760 ◽  
Author(s):  
Yaron S. Feldheim ◽  
Tal Zusman ◽  
Anya Kapach ◽  
Gil Segal

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