Impairment in karrikin but not strigolactone sensing enhances root skewing in Arabidopsis thaliana

Autor: Yannick Guerringue, Julia M. Davies, Elsa Matthus, Fiona J. C. Jamieson, Stéphanie M. Swarbreck
Přispěvatelé: Swarbreck, Stephanie [0000-0001-8355-7354], Apollo - University of Cambridge Repository
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: The Plant Journal
ISSN: 1365-313X
0960-7412
Popis: Summary Roots form highly complex systems varying in growth direction and branching pattern to forage for nutrients efficiently. Here mutations in the KAI2 (KARRIKIN INSENSITIVE) α/β‐fold hydrolase and the MAX2 (MORE AXILLARY GROWTH 2) F‐box leucine‐rich protein, which together perceive karrikins (smoke‐derived butenolides), caused alteration in root skewing in Arabidopsis thaliana. This phenotype was independent of endogenous strigolactones perception by the D14 α/β‐fold hydrolase and MAX2. Thus, KAI2/MAX2 effect on root growth may be through the perception of endogenous KAI2‐ligands (KLs), which have yet to be identified. Upon perception of a ligand, a KAI2/MAX2 complex is formed together with additional target proteins before ubiquitination and degradation through the 26S proteasome. Using a genetic approach, we show that SMAX1 (SUPPRESSOR OF MAX2‐1)/SMXL2 and SMXL6,7,8 (SUPPRESSOR OF MAX2‐1‐LIKE) are also likely degradation targets for the KAI2/MAX2 complex in the context of root skewing. In A. thaliana therefore, KAI2 and MAX2 act to limit root skewing, while kai2's gravitropic and mechano‐sensing responses remained largely unaffected. Many proteins are involved in root skewing, and we investigated the link between MAX2 and two members of the SKS/SKU family. Though KLs are yet to be identified in plants, our data support the hypothesis that they are present and can affect root skewing.
Significance Statement Arabidopsis thaliana mutants deficient in karrikins/KAI2‐ligand (KL) perception display an exaggerated root‐skewing phenotype, which is not readily explained by impairments in their mechano‐sensing and gravitropic responses. Strigolactones (SLs) belong to a recently characterised set of phytohormones. Their role in root skewing in Arabidopsis has been hypothesized, but no evidence supporting a role for SL in influencing root skewing was found here. Rather, results support a role for as‐yet unidentified endogenous KLs.
Databáze: OpenAIRE
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