Early transcriptional response to gravistimulation in poplar without phototropic confounding factors

Lopez David, Franchel Jérôme, Venisse Jean-Stéphane, Drevet Patricia, Label Philippe, Coutand Catherine, Roeckel-Drevet Patricia. 2021. Early transcriptional response to gravistimulation in poplar without phototropic confounding factors. AoB Plants, 13 (1), 17 p.

Quartile : Q2, Sujet : ECOLOGY / Quartile : Q2, Sujet : PLANT SCIENCES

Résumé : In response to gravistimulation under anisotropic light, tree stems showing an active cambium produce reaction wood that redirects the axis of the trees. Several studies have described transcriptomic or proteomic models of reaction wood relative to the opposite wood. However, the mechanisms leading to the formation of reaction wood are difficult to decipher because so many environmental factors can induce various signalling pathways leading to this developmental reprogramming. Using an innovative isotropic device where the phototropic response does not interfere with gravistimulation we characterized the early molecular responses occurring in the stem of poplar after gravistimulation in an isotropic environment, and without deformation of the stem. After 30 min tilting at 35° under anisotropic light, we collected the upper and lower xylems from the inclined stems. Controls were collected from vertical stems. We used a microarray approach to identify differentially expressed transcripts. High-throughput real-time PCR allowed a kinetic experiment at 0, 30, 120 and 180 min after tilting at 35°, with candidate genes. We identified 668 differentially expressed transcripts, from which we selected 153 candidates for additional Fluidigm qPCR assessment. Five candidate co-expression gene clusters have been identified after the kinetic monitoring of the expression of candidate genes. Gene ontology analyses indicate that molecular reprogramming of processes such as 'wood cell expansion', 'cell wall reorganization' and 'programmed cell death' occur as early as 30 min after gravistimulation. Of note is that the change in the expression of different genes involves a fine regulation of gibberellin and brassinosteroid pathways as well as flavonoid and phosphoinositide pathways. Our experimental set-up allowed the identification of genes regulated in early gravitropic response without the bias introduced by phototropic and stem bending responses.

Mots-clés Agrovoc : gravitropisme, bois de réaction, paroi cellulaire, Populus alba, Populus tremula, xylème, port de la plante, tige

Mots-clés complémentaires : gravistimulation

Mots-clés libres : Tree physiology, Gravitropism, Transcriptomics

Classification Agris : F62 - Physiologie végétale - Croissance et développement
F30 - Génétique et amélioration des plantes

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

Auteurs et affiliations

• Lopez David, CIRAD-BIOS-UMR AGAP (FRA)
• Franchel Jérôme, Université Blaise Pascal (FRA)
• Venisse Jean-Stéphane, INRAE (FRA)
• Drevet Patricia, Université Blaise Pascal (FRA)
• Label Philippe, Université Blaise Pascal (FRA)
• Coutand Catherine, INRAE (FRA)
• Roeckel-Drevet Patricia, Université Blaise Pascal (FRA) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/597754/)

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