CLAVATA-WUSCHEL signaling in the shoot meristem

Abstract

Shoot meristems are maintained by pluripotent stem cells that are controlled by CLAVATA-WUSCHEL feedback signaling. This pathway, which coordinates stem cell proliferation with differentiation, was first identified in Arabidopsis, but appears to be conserved in diverse higher plant species. In this Review, we highlight the commonalities and differences between CLAVATA-WUSCHEL pathways in different species, with an emphasis on Arabidopsis, maize, rice and tomato. We focus on stem cell control in shoot meristems, but also briefly discuss the role of these signaling components in root meristems.

Dual CLAVATA3 peptides in Arabidopsis shoot stem cell signaling

“…The CLAVATA-WUSHCEL (CLV-WUS) feedback signaling pathway, first discovered in Arabidopsis thaliana , appears to be conserved for stem cell control in the SAM of higher plants (Somssich et al, 2016; Yamaguchi et al, 2016). The CLAVATA3 peptide (CLV3p) produced in the stem cells of the shoot apex functions as a signaling ligand of the CLAVATA1 (CLV1) and related receptor kinases to restrict the level of WUS transcription factor in the organizing center (OC), which promotes CLV3 expression via cell-to-cell communication through plasmodesmata and the stem cell fate but represses differentiation (Fletcher et al, 1999; Yadav et al, 2011; Yadav et al, 2013; Lee, 2014; Somssich et al, 2016; Yamaguchi et al, 2016). The signaling components between CLV3-CLV1 and WUS remains enigmatic despite great efforts in the past two decades.…”

“…The signaling components between CLV3-CLV1 and WUS remains enigmatic despite great efforts in the past two decades. Although loss-of-function and various genetic manipulations of CLV3 expression have facilitated the analysis of long-term phenotypes, exogenous application of physiological CLV3 peptides complementing clv3 mutants will aid in the discovery of primary and dynamic processes in peptide-receptor signaling (Somssich et al, 2016; Yamaguchi et al, 2016). …”

“…However, the performance of chemically synthesized 12-amino-acid MCLV3p and 13-amino-acid [Ara 3 ]CLV3p have not been carefully compared due to the difficulties of determining the stereoselective nature of glycosidic linkages in chemical synthesis of the pure [Ara 3 ]CLV3 peptides (Shinohara and Matsubayashi, 2013). Inevitably, high concentrations of synthetic CLV3/EMBRYO SURROUNDING REGION-related (CLE) peptides in the range of 1-100 μM have been commonly applied in the measurement of SAM size in biossays in different plant species, leading to concerns about biological relevance of the findings (Somssich et al, 2016; Yamaguchi et al, 2016). …”

Homeobox genes encoding WOX transcription factors in the flowering parasitic plant Monotropa hypopitys

“…Механизм регуляции данного процесса при знан консервативным для цветковых растений разных видов. Наиболее подробно он исследован в модельном растении Arabidopsis thaliana (Somssich et al, 2016). Под центральной зоной располагается организующий центр.…”

“…Механизм терминации цвет ковой меристемы включает в себя регуляторную петлю WUS-AGAMOUS (AG) (Lenhard et al, 2001), которая начинается с активации транскрипции AG совместными усилиями WUS и LEAFY (LFY) (Lohmann et al, 2001) и заканчивается репрессией WUS в центре цветковой меристемы одновременно или сразу после инициации плодолистиков (Sun et al, 2009;Liu et al, 2011). В резуль тате цветок с фиксированным количеством органов фор мируется при подавлении экспрессии WUS в момент ин дукции терминации цветковой меристемы, разный для каждого вида растений, что, предположительно, является одной из причин невероятного разнообразия цветковых форм (Somssich et al, 2016) среди более чем 350 000 видов покрытосеменных растений (Chapman, 2009).…”