SERK Receptor-Like Kinases Control Division Patterns of Vascular Precursors and Ground Tissue Stem Cells during Embryo Development in Arabidopsis

First author: Huiqiang Li; Affiliations: Lanzhou University (兰州大学): Lanzhou, China

Corresponding author: Xiaoping Gou

During embryo development, the vascular precursors and the ground tissue stem cells divide to renew themselves and produce the vascular tissue, endodermal cells and cortical cells. However, the molecular mechanisms regulating division of these stem cells have remained largely elusive. In this study, we show that loss function of SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) genes results in aberrant embryo development. Fewer cortical, endodermal and vascular cells are generated in the embryo of serk1 serk2 bak1 triple mutants. WUSCHEL RELATED HOMEOBOX 5 ( WOX5) is ectopically expressed in vascular cells of serk1 serk2 bak1 embryos. The first transverse division of the vascular precursors in mid-globular embryos and the second asymmetric division of the ground tissue stem cells in early-heart embryos are abnormally altered to a longitudinal division. The embryo defects can be partially rescued by constitutively activated mitogen-activated protein kinase (MAPK) kinase kinase YODA (YDA) and MAPK kinase MKK5. Our results revealed that SERK-mediated signals regulate division patterns of the vascular precursors and the ground tissue stem cells likely via the YDA-MKK4/5 cascade during embryo development.

在胚胎发育过程中，维管祖细胞和基本组织干细胞会分裂，在更新自身的同时产生维管组织、内皮层细胞和皮层细胞。然而，调控这些干细胞分裂的分子机制还不是很清楚。本文的研究中，作者揭示SERK基因的功能缺失会导致胚胎发育异常。在serk1 serk2 bak1三突植株中，胚胎的皮层、内皮层和维管细胞产生的比较少。另外，serk1 serk2 bak1三突植株中的WOX5在维管细胞中异位表达。维管祖细胞在球形胚中期的第一次横向分裂和基本组织干细胞在心形胚早期的第二次不对称分裂都变成了纵向分裂。组成型激活丝裂原活化蛋白激酶MAPK激酶激酶YDA和MAPK激酶MKK5能够部分拯救三突植株的胚胎缺陷表型。本文的研究揭示了胚胎发育过程中，SERK介导的信号通过YDA-MKK4/5级联调控维管祖细胞和基本组织干细胞的分裂模式。

通讯：苟小平（http://lifesc.lzu.edu.cn/en/faculty/3302.html）

个人简介：1991-1995年，四川大学，学士；1995-1998年，四川大学，硕士；1998-2001年，四川大学，博士；2001-2009年，美国俄克拉荷马大学，博士后。

研究方向：植物生殖生物学与类受体样蛋白的功能分析。

doi: https://doi.org/10.1016/j.molp.2019.04.011

Journal: Molecular Plant

Published date: May 03, 2019