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Strigolactones regulate sepal senescence in Arabidopsis
Xi Xu1,2, Rubina Jibran2, Yanting Wang3
1Massey University, School of Fundamental Sciences, Palmerston North, New Zealand.
Journal of Experimental Botany
|May 10, 2021
Summary
Strigolactones regulate flower sepal longevity, a novel role for these plant hormones. Mutations in strigolactone biosynthesis (MAX1) and signaling (AtD14) genes in Arabidopsis thaliana delay sepal senescence.
Area of Science:
- Plant Biology
- Molecular Genetics
- Hormone Signaling
Background:
- Flower sepals exhibit diverse lifespans, crucial for reproductive success, yet the mechanisms controlling sepal longevity remain largely unknown.
- Strigolactones are plant hormones primarily known for regulating shoot branching, root development, and symbiotic interactions.
Purpose of the Study:
- To identify genetic factors controlling sepal longevity and explore the role of strigolactones in floral senescence.
- To investigate the function of strigolactone biosynthesis and signaling pathways in the context of sepal aging.
Main Methods:
- Conducted a forward genetic screen for mutants exhibiting delayed sepal senescence in Arabidopsis thaliana.
- Characterized mutations in strigolactone biosynthesis (MAX1) and signaling (AtD14) genes.
- Performed transient expression assays to assess protein activity and analyzed transcript abundance under stress conditions.
Main Results:
- Identified two Arabidopsis mutants with significantly delayed sepal senescence, harboring mutations in MAX1 and AtD14.
- The AtD14 mutation altered a key catalytic residue (Ser97 to Phe), and the MAX1 mutation affected a conserved active site residue (Gly469 to Arg), impairing protein function.
- Strigolactone activity is essential for the completion of both developmental and stress-induced sepal senescence, similar to ethylene and abscisic acid.
Conclusions:
- This study reveals a novel role for strigolactones in regulating sepal longevity and floral senescence.
- The findings highlight an intricate interplay between sugar starvation, strigolactone biosynthesis, and signaling pathways in controlling senescence.
- Strigolactone signaling is a critical component of the senescence regulatory network in flowers.
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