pin2 mutant agravitropic root phenotype is conditional and nutrient-sensitive

Thomas Marion, Soriano Alexandre, O’Connor Claire, Crabos Amandine, Nacry Philippe, Thompson Megan, Hrabak Estelle, Divol Fanchon, Péret Benjamin. 2023. pin2 mutant agravitropic root phenotype is conditional and nutrient-sensitive. Plant Science, 329:111606, 11 p.

https://doi.org/10.1016/j.plantsci.2023.111606

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Résumé : Plants have the capacity to sense and adapt to environmental factors using the phytohormone auxin as a major regulator of tropism and development. Among these responses, gravitropism is essential for plant roots to grow downward in the search for nutrients and water. We discovered a new mutant allele of the auxin efflux transporter PIN2 that revealed that pin2 agravitropic root mutants are conditional and nutrient-sensitive. We describe that nutrient composition of the medium, rather than osmolarity, can revert the agravitropic root phenotype of pin2. Indeed, on phosphorus- and nitrogen-deprived media, the agravitropic root defect was restored independently of primary root growth levels. Slow and fast auxin responses were evaluated using DR5 and R2D2 probes, respectively, and revealed a strong modulation by nutrient composition of the culture medium. We evaluated the role of PIN and AUX auxin transporters and demonstrated that neither PIN3 nor AUX1 are involved in this process. However, we observed the ectopic expression of PIN1 in the epidermis in the pin2 mutant background associated with permissive, but not restrictive, conditions. This ectopic expression was associated with a restoration of the asymmetric accumulation of auxin necessary for the reorientation of the root according to gravity. These observations suggest a strong regulation of auxin distribution by nutrients availability, directly impacting root's ability to drive their gravitropic response.

Mots-clés Agrovoc : phénotype, auxine, gravitropisme, Arabidopsis thaliana, mutant, facteur du milieu, nutriment végétal essentiel, substance de croissance végétale

Mots-clés libres : Polar auxin transport, PIN1, PIN2, Gravitropism, Nutrients, Conditional phenotype

Classification Agris : F50 - Anatomie et morphologie des plantes
F60 - Physiologie et biochimie végétale
F61 - Physiologie végétale - Nutrition

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Agences de financement hors UE : Montpellier SupAgro

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