When: Thursday, March 6, 2025 | 2:00 PM – 3:30 PM
International Barley Hub is pleased to announce the next in the 2025 series of seminars: “On the role of stem cell regulators in shaping barley spike architecture”. This seminar will be presented by Isaia Vardanega, Postdoctoral Researcher, Heinrich-Heine University.
Summary:
Grasses exhibit a wide variety of inflorescence architectures, from the complex branched inflorescences of the Oryzeae tribe (rice), where grains develop on primary and secondary branches, to simple spike-type inflorescences of the Triticeae tribe (e.g. barley and wheat), where grains develop on short vestigial axes called rachillae. The inflorescence architecture depends on shape, longevity, and determinacy of meristems that direct the growth of the main rachis and lateral branches. However, how individual meristem activities are determined and integrated within complex inflorescences is not yet understood. Here, we found that the activity of distinct meristems in the barley inflorescence is coordinated by a signalling pathway comprising the receptor-like kinase Hordeum vulgare CLAVATA1 (HvCLV1) and the secreted CLAVATA3/EMBRYO-SURROUNDING REGION RELATED (CLE)-family peptide FON2-LIKE CLE PROTEIN1 (HvFCP1). HvFCP1 interacts with HvCLV1 to promote spikelet formation but restricts inflorescence meristem and rachilla proliferation. Hvfcp1 or Hvclv1 mutants generated branched inflorescences with additional rows of spikelets and supernumerary florets. Transcriptome analysis suggested that HvFCP1/HvCLV1 signalling controls inflorescence branching through the regulation of trehalose-6-phosphate synthesis and sugar transport. Insights from previous studies in Arabidopsis Thaliana suggested a possible compensatory effect on the Hvclv1 inflorescence phenotype by members of the closely related Hordeum vulgare BARELY ANY MERISTEM (HvBAM) gene family. Here, we investigated the function of two additional receptor-like kinases, HvBAM1 and HvBAM2, and their genetic interaction with HvCLV1 by the generation of higher-order mutants. While the single Hvbam mutants only slightly affected the morphology of the barley spike, mutant combinations with Hvclv1 displayed new inflorescence architectures including the formation of branches and multi-floret spikelets. The phenotype of different mutants was characterised at cellular resolution by single-cell RNA-seq and single-molecule RNA FISH. With this study, we uncovered the role of CLAVATA receptors in the regulation of different meristem types comprising the barley spike and demonstrated the potential to engineer inflorescence architecture through the specific regulation of meristem activities.
Speakers bio:
Isaia Vardanega:
Date: 01/03/2018
Master degree in Cellular and Molecular biology at Alma Mater Studiorum, University of Bologna, Bologna, Italy.
Dates (from-to): 23/04/2018 – 28/06/2018
Graduate assistant at Silvio Salvi lab, Alma Mater Studiorum, University of Bologna, Italy.
Project: Barley root gravitropism – characterization of the barely gene ENHANCED GRAVITROPISM 2 (EGT2).
Dates (from-to): 01/07/2018 – 31/12/2018
Graduate assistant at Frank Hochholdinger lab, Rheinische Friedrich-Wilhelms-Universität Bonn, Germany.
Project: Barley root gravitropism – characterization of the barely gene ENHANCED GRAVITROPISM 2 (EGT2).
Dates (from-to): 01/07/2019 – 11/07/2024
PhD student at Rüdiger Simon lab, Heinrich-Heine-Universität, Düsseldorf, Germany.
Project: Barley inflorescence development – the role of CLAVATA signalling pathways in shaping barley inflorescence architecture.
Dates (from-to): 01/08/2024 – now
Postdoctoral researcher at Rüdiger Simon lab, Heinrich-Heine-Universität, Düsseldorf, Germany.
Project: Barley inflorescence development – the role of CLAVATA signalling pathways in shaping barley inflorescence architecture.
Please note the recording of this seminar will soon be available.