Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development

ABSTRACT The role of cytokinin among plant hormones in seed development remains largely unknown. The Arabidopsis response regulator 21 (ARR21) is one of the cytokinin response regulators and a Type‐B ARR with a nuclear localization signal and a GARP motif similar to the MYB‐like DNA‐binding domain....

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Main Authors: Sujeong Jeong, Inyoung Kim, Hyun Uk Kim
Format: Article
Language:English
Published: Wiley 2025-07-01
Series:Plant Direct
Subjects:
Online Access:https://doi.org/10.1002/pld3.70091
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author Sujeong Jeong
Inyoung Kim
Hyun Uk Kim
author_facet Sujeong Jeong
Inyoung Kim
Hyun Uk Kim
author_sort Sujeong Jeong
collection DOAJ
description ABSTRACT The role of cytokinin among plant hormones in seed development remains largely unknown. The Arabidopsis response regulator 21 (ARR21) is one of the cytokinin response regulators and a Type‐B ARR with a nuclear localization signal and a GARP motif similar to the MYB‐like DNA‐binding domain. ARR21‐sGreen fluorescent protein (GFP) signals were localized within the nucleus, and ARR21 showed the highest expression levels in developing seeds. In addition, histochemical analysis revealed ARR21 expression in the silique coats, chalazal seed coat, chalazal endosperm, and throughout the developing seed at 6 days after pollination. Two independent mutants were generated using the CRISPR/Cas9 system: arr21‐3 (51 bp in‐frame deletion) and arr21‐4 (2 bp insertion). The seed size and weight of the arr21 mutants decreased by an average of 10.7% and 37%, respectively, compared to the wild‐type (WT). In arr21 mutants, the cotyledon length of embryos and the size of seed coat cells were reduced. Seed‐specific overexpression of ARR21 in arr21‐4 restored the seed length to WT levels. This study suggests that ARR21 regulates seed size by functioning in the chalazal endosperm and embryo, thereby providing insights into the role of cytokinin in seed development.
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spelling doaj-art-33fee4de3e3746cda40aa3fef7d8a3552025-08-20T03:31:37ZengWileyPlant Direct2475-44552025-07-0197n/an/a10.1002/pld3.70091Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed DevelopmentSujeong Jeong0Inyoung Kim1Hyun Uk Kim2Department of Bioindustry and Bioresource Engineering Sejong University Seoul Republic of KoreaDepartment of Molecular Biology Sejong University Seoul Republic of KoreaDepartment of Bioindustry and Bioresource Engineering Sejong University Seoul Republic of KoreaABSTRACT The role of cytokinin among plant hormones in seed development remains largely unknown. The Arabidopsis response regulator 21 (ARR21) is one of the cytokinin response regulators and a Type‐B ARR with a nuclear localization signal and a GARP motif similar to the MYB‐like DNA‐binding domain. ARR21‐sGreen fluorescent protein (GFP) signals were localized within the nucleus, and ARR21 showed the highest expression levels in developing seeds. In addition, histochemical analysis revealed ARR21 expression in the silique coats, chalazal seed coat, chalazal endosperm, and throughout the developing seed at 6 days after pollination. Two independent mutants were generated using the CRISPR/Cas9 system: arr21‐3 (51 bp in‐frame deletion) and arr21‐4 (2 bp insertion). The seed size and weight of the arr21 mutants decreased by an average of 10.7% and 37%, respectively, compared to the wild‐type (WT). In arr21 mutants, the cotyledon length of embryos and the size of seed coat cells were reduced. Seed‐specific overexpression of ARR21 in arr21‐4 restored the seed length to WT levels. This study suggests that ARR21 regulates seed size by functioning in the chalazal endosperm and embryo, thereby providing insights into the role of cytokinin in seed development.https://doi.org/10.1002/pld3.70091Arabidopsis response regulatorARR21cytokininseed developmentseed sizetranscription factor
spellingShingle Sujeong Jeong
Inyoung Kim
Hyun Uk Kim
Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
Plant Direct
Arabidopsis response regulator
ARR21
cytokinin
seed development
seed size
transcription factor
title Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
title_full Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
title_fullStr Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
title_full_unstemmed Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
title_short Molecular Characterization of Cytokinin Response Regulator ARR21 in Arabidopsis Seed Development
title_sort molecular characterization of cytokinin response regulator arr21 in arabidopsis seed development
topic Arabidopsis response regulator
ARR21
cytokinin
seed development
seed size
transcription factor
url https://doi.org/10.1002/pld3.70091
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AT inyoungkim molecularcharacterizationofcytokininresponseregulatorarr21inarabidopsisseeddevelopment
AT hyunukkim molecularcharacterizationofcytokininresponseregulatorarr21inarabidopsisseeddevelopment