Regulation of lignin biosynthesis by an atypical bHLH protein CmHLB in Chrysanthemum.
J Exp Bot
; 73(8): 2403-2419, 2022 04 18.
Article
em En
| MEDLINE
| ID: mdl-35090011
ABSTRACT
Stem mechanical strength is one of the most important agronomic traits that affects the resistance of plants against insects and lodging, and plays an essential role in the quality and yield of plants. Several transcription factors regulate mechanical strength in crops. However, mechanisms of stem strength formation and regulation remain largely unexplored, especially in ornamental plants. In this study, we identified an atypical bHLH transcription factor CmHLB (HLH PROTEIN INVOLVED IN LIGNIN BIOSYNTHESIS) in chrysanthemum, belonging to a small bHLH sub-family - the PACLOBUTRAZOL RESISTANCE (PRE) family. Overexpression of CmHLB in chrysanthemum significantly increased mechanical strength of the stem, cell wall thickness, and lignin content, compared with the wild type. In contrast, CmHLB RNA interference lines exhibited the opposite phenotypes. RNA-seq analysis indicated that CmHLB promoted the expression of genes involved in lignin biosynthesis. Furthermore, we demonstrated that CmHLB interacted with Chrysanthemum KNOTTED ARABIDOPSIS THALIANA7 (CmKNAT7) through the KNOX2 domain, which has a conserved function, i.e. it negatively regulates secondary cell wall formation of fibres and lignin biosynthesis. Collectively, our results reveal a novel role for CmHLB in regulating lignin biosynthesis by interacting with CmKNAT7 and affecting stem mechanical strength in Chrysanthemum.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arabidopsis
/
Chrysanthemum
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Exp Bot
Assunto da revista:
BOTANICA
Ano de publicação:
2022
Tipo de documento:
Article