Signaling of Cell Fate Decisions by CLAVATA3 in Arabidopsis Shoot Meristems

Abstract

In higher plants, organogenesis occurs continuously from self-renewing apical meristems. Arabidopsis thaliana plants with loss-of-function mutations in the CLAVATA (CLV1, 2, and 3) genes have enlarged meristems and generate extra floral organs. Genetic analysis indicates that CLV1, which encodes a receptor kinase, acts with CLV3 to control the balance between meristem cell proliferation and differentiation. CLV3 encodes a small, predicted extracellular protein. CLV3 acts nonautonomously in meristems and is expressed at the meristem surface overlying the CLV1 domain. These proteins may act as a ligand-receptor pair in a signal transduction pathway, coordinating growth between adjacent meristematic regions.

COP1 mediates the coordination of root and shoot growth by light through modulation of PIN1- and PIN2-dependent auxin transport in Arabidopsis

“…We thus hypothesized an involvement of shoot-derived auxin and shoot-to-root PAT in the control of root growth by light. To verify this hypothesis, we first lowered auxin levels in the shoot apical meristem through ethanolinducible expression of the bacterial gene iaaL, which reduces free auxin by conjugating IAA to Lys (Jensen et al, 1998), in the CLAVATA3 (CLV3) (Fletcher et al, 1999) S9). Taken together, these data support the idea that darkness inhibits shoot-to-root PAT.…”

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

“…The Arabidopsis genome contains 31 CLE genes encoding 26 short peptides. Although some of the CLE genes, have been shown to unequivocally regulate meristem size (Fletcher et al 1999;Fiers et al 2005), not much is known about the functions of the other members. Recent work (Ito et al 2006) suggests that CLE 27 may play a similar role in meristem development.…”

RGF1 INSENSITIVE 1 to 5, a group of LRR receptor-like kinases, are essential for the perception of root meristem growth factor 1 in Arabidopsis thaliana

“…Biological functions of several CLE peptides have been revealed. For example, CLV3 and CLE40 are responsible for shoot and root apical meristem maintenance, respectively [9,11,12]. CLV3 is perceived by three different receptors or putative receptors, CLAVA-TA1 (CLV1), CLAVATA 2 (CLV2)-CORYNE (CRN), and RPK2/TOAD2, to limit stem cell size by restricting the expression of a homeodomain transcription factor, WUSCHEL (WUS), via a negative feedback loop [13][14][15][16][17][18].…”