Establishment of the Embryonic Shoot Meristem Involves Activation of Two Classes of Genes with Opposing Functions for Meristem Activities

Establishment of the Embryonic Shoot Meristem Involves Activation of Two Classes of Genes with Opposing Functions for Meristem Activities

The shoot meristem, a stem-cell-containing tissue initiated during plant embryogenesis, is responsible for continuous shoot organ production in postembryonic development. Although key regulatory factors including <i>KNOX</i> genes are responsible for stem cell maintenance in the shoot me...

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Bibliographic Details
Main Authors: Mitsuhiro Aida, Yuka Tsubakimoto, Satoko Shimizu, Hiroyuki Ogisu, Masako Kamiya, Ryosuke Iwamoto, Seiji Takeda, Md Rezaul Karim, Masaharu Mizutani, Michael Lenhard, Masao Tasaka
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:International Journal of Molecular Sciences
Subjects:
shoot meristem
embryogenesis
stem cell
boundary
transcription factor
cytochrome P450
Online Access:https://www.mdpi.com/1422-0067/21/16/5864
Description
Summary:The shoot meristem, a stem-cell-containing tissue initiated during plant embryogenesis, is responsible for continuous shoot organ production in postembryonic development. Although key regulatory factors including <i>KNOX</i> genes are responsible for stem cell maintenance in the shoot meristem, how the onset of such factors is regulated during embryogenesis is elusive. Here, we present evidence that the two <i>KNOX</i> genes <i>STM</i> and <i>KNAT6</i> together with the two other regulatory genes <i>BLR</i> and <i>LAS</i> are functionally important downstream genes of <i>CUC1</i> and <i>CUC2</i>, which are a redundant pair of genes that specify the embryonic shoot organ boundary. Combined expression of <i>STM</i> with any of <i>KNAT6</i>, <i>BLR</i>, and <i>LAS</i> can efficiently rescue the defects of shoot meristem formation and/or separation of cotyledons in <i>cuc1</i> <i>cuc2</i> double mutants. In addition, <i>CUC1</i> and <i>CUC2</i> are also required for the activation of <i>KLU</i>, a cytochrome P450-encoding gene known to restrict organ production, and <i>KLU</i> counteracts <i>STM</i> in the promotion of meristem activity, providing a possible balancing mechanism for shoot meristem maintenance. Together, these results establish the roles for <i>CUC1</i> and <i>CUC2</i> in coordinating the activation of two classes of genes with opposite effects on shoot meristem activity.
ISSN:1661-6596
1422-0067

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