1. The Arabidopsis RLCK VI_A2 Kinase Controls Seedling and Plant Growth in Parallel with Gibberellin.
- Author
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Valkai I, Kénesi E, Domonkos I, Ayaydin F, Tarkowská D, Strnad M, Faragó A, Bodai L, and Fehér A
- Subjects
- Arabidopsis drug effects, Arabidopsis enzymology, Arabidopsis growth & development, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors genetics, Basic Helix-Loop-Helix Transcription Factors metabolism, Cotyledon drug effects, Cotyledon enzymology, Cotyledon growth & development, DNA, Bacterial genetics, DNA, Bacterial metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gibberellins metabolism, Gibberellins pharmacology, Hypocotyl drug effects, Hypocotyl enzymology, Hypocotyl growth & development, Indoleacetic Acids metabolism, Indoleacetic Acids pharmacology, Mutagenesis, Insertional, Plant Growth Regulators pharmacology, Plants, Genetically Modified, Protein Serine-Threonine Kinases metabolism, Seedlings drug effects, Seedlings enzymology, Seedlings growth & development, Transcription Factors genetics, Transcription Factors metabolism, Transcriptome, Arabidopsis genetics, Cotyledon genetics, Gene Expression Regulation, Plant, Hypocotyl genetics, Protein Serine-Threonine Kinases genetics, Seedlings genetics
- Abstract
The plant-specific receptor-like cytoplasmic kinases (RLCKs) form a large, poorly characterized family. Members of the RLCK VI_A class of dicots have a unique characteristic: their activity is regulated by Rho-of-plants (ROP) GTPases. The biological function of one of these kinases was investigated using a T-DNA insertion mutant and RNA interference. Loss of RLCK VI_A2 function resulted in restricted cell expansion and seedling growth. Although these phenotypes could be rescued by exogenous gibberellin, the mutant did not exhibit lower levels of active gibberellins nor decreased gibberellin sensitivity. Transcriptome analysis confirmed that gibberellin is not the direct target of the kinase; its absence rather affected the metabolism and signalling of other hormones such as auxin. It is hypothesized that gibberellins and the RLCK VI_A2 kinase act in parallel to regulate cell expansion and plant growth. Gene expression studies also indicated that the kinase might have an overlapping role with the transcription factor circuit (PIF4-BZR1-ARF6) controlling skotomorphogenesis-related hypocotyl/cotyledon elongation. Furthermore, the transcriptomic changes revealed that the loss of RLCK VI_A2 function alters cellular processes that are associated with cell membranes, take place at the cell periphery or in the apoplast, and are related to cellular transport and/or cell wall reorganisation., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
- Published
- 2020
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