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#meristem

9 public questions tagged with this topic.

plant Development -ll

STM gene maintains:

SHOOT MERISTEMLESS encodes KNOX1 class homeobox protein expressed throughout shoot apical meristem dome but sharply downregulated in incipient leaf primordia by ASYMMETRIC LEAVES1/2 repression pathway. STM prevents premature differentiation by promoting cytokinin biosynthesis through IPT7 activation, repressing gibberellin 20-oxidase genes maintaining low active GA, repressing CUC boundary regulators at proper domains, and protecting stem cell identity. Strong stm mutants fail to establish embryonic SAM, exhibit fused cotyledons, lack vegetative growth, arrest as seedlings, demonstrating absolute requirement for maintaining shoot meristem identity and indeterminate self-renewal capacity.

Ref: Long & Barton, Development 1998; Laux et al.: STM maintains shoot meristem identity and indeterminate growth, KNOX.

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plant Development -ll

WOX5 contributes to:

WOX5 WUSCHEL-related homeobox 5 transcription factor is exclusively expressed in quiescent center cells of root apical meristem functioning analogously to shoot WUS. It moves non-cell-autonomously to surrounding cortex/endodermis and columella initials repressing differentiation-promoting transcription factor CYCLING DOF FACTOR 4 and maintaining stem cell identity. WOX5 sustains PLT gradient, auxin homeostasis, and represses differentiation via local chromatin modifications. Its expression maintained by SHR/SCR and PLT feedback as well as auxin, illustrating conserved WOX-based organizing center mechanism preserving root stem cell reservoir enabling continuous indeterminate growth.

Ref: Sarkar et al., Nature 2007; Taiz Plant Phys: WOX5 maintains root initial cells and QC organization.

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