The signaling peptide-encoding genes CLE16, CLE17 and CLE27 are dispensable for Arabidopsis shoot apical meristem activity

Abstract

The shoot apical meristem produces all of the leaves, stems and flowers of a flowering plant from a reservoir of stem cells at its growing tip. In Arabidopsis, the small polypeptide signaling molecule CLAVATA3 (CLV3), a member of the CLV3/EMBRYO SURROUNDING REGION-RELATED (CLE) gene family, is a key component of a negative feedback loop that maintains stem cell activity in shoot and floral meristems throughout development. Because in some plant species multiple CLE genes are involved in regulating shoot apical meristem activity, we tested the hypothesis that CLE genes other than CLV3 might function in stem cell homeostasis in Arabidopsis. We identified three Arabidopsis CLE genes expressed in the post-embryonic shoot apical meristem, generated loss-of-function alleles using genome editing, and analyzed the meristem phenotypes of the resulting mutant plants. We found that null mutations in CLE16, CLE17 or CLE27 affected neither vegetative nor reproductive shoot meristem activity under normal growth conditions, although CLE27 appears to slightly prolong vegetative growth. Our results indicate that the CLE16, CLE17 and CLE27 genes have largely redundant roles in the Arabidopsis shoot apical meristem and/or regulate meristem activity only under specific environmental conditions.

BAM1/2 receptor kinase signaling drives CLE peptide-mediated formative cell divisions in Arabidopsis roots

“…3 C ). To further confirm the biological relevance of the peptide assays, we screened a collection of CRISPR-generated cle null mutants and found significantly reduced CEI/CEID divisions, comparable to bam1 single mutants, in three independent cle16 mutant alleles ( 30 ) ( Fig. 3 D and SI Appendix , Fig.…”

“…CLE13p::GUS and CLE16p::GUS lines ( 26 ) were obtained from The Arabidopsis Information Resource. Additional cle16 alleles ( cle16-2 and cle16-3 ) are previously described ( 30 ).…”

Identification and Functional Analysis of the CLAVATA3/EMBRYO SURROUNDING REGION (CLE) Gene Family in Wheat

“…AtCLE16, 17 and 20 were also placed into the Group (Supplementary Figure S2). In Arabidopsis , AtCLE16 and 17 show functional redundancy for Arabidopsis SAM activity [50], and AtCLE17 and 20 can affect root development [51]. Predicted expression patterns indicate that TaCLE2 and TaCLE20 are expressed in various tissues at different stages with a low expression level in roots except for TaCLE2b (Supplementary Figure S3).…”

Root Breeding in the Post-Genomics Era: From Concept to Practice in Apple

“…Since the discovery of the first plant peptide hormone and after years of exploration and research, peptide hormones have been gradually valued and widely studied because of their important role in regulating plant growth and development and adapting to environmental conditions. C-TERMINALLY ENCODED PEPTIDE (CEP) exerts an inhibitory effect on the root growth of apple seedlings, indicating that MdCEP1 negatively regulates root development [ 159 ]. The CLE16, CLE17, and CLE27 members of the CLAVATA 3/EMBRYO SURROUNDING REGION-RELATED (CLE) gene family play largely redundant roles in the Arabidopsis root apical meristem and/or regulate meristem activity under only specific environmental conditions [ 160 ] ( Figure 3 ).…”