Early molecular events involved in Pinus pinaster Ait. somatic embryo development under reduced water availability: transcriptomic and proteomic analyses.
Maritime pine somatic embryos (SEs) require a reduction in water availability (high gellan gum concentration in the maturation medium) to reach the cotyledonary stage. This key switch, reported specifically for pine species, is not yet well understood. To facilitate the use of somatic embryogenesis for mass propagation of conifers, we need a better understanding of embryo development. Comparison of both transcriptome (Illumina RNA sequencing) and proteome [two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis with mass spectrometry (MS) identification] of immature SEs, cultured on either high (9G) or low (4G) gellan gum concentration, was performed, together with analysis of water content, fresh and dry mass, endogenous abscisic acid (ABA; gas chromatography-MS), soluble sugars (high-pressure liquid chromatography), starch and confocal laser microscope observations. This multiscale, integrated analysis was used to unravel early molecular and physiological events involved in SE development. Under unfavorable conditions (4G), the glycolytic pathway was enhanced, possibly in relation to cell proliferation that may be antagonistic to SE development. Under favorable conditions (9G), SEs adapted to culture constraint by activating specific protective pathways, and ABA-mediated molecular and physiological responses promoting embryo development. Our results suggest that on 9G, germin-like protein and ubiquitin-protein ligase could be used as predictive markers of SE development, whereas protein phosphatase 2C could be a biomarker for culture adaptive responses. This is the first characterization of early molecular mechanisms involved in the development of pine SEs following an increase in gellan gum concentration in the maturation medium, and it is also the first report on somatic embryogenesis in conifers combining transcriptomic and proteomic datasets.
INRA, UR 0588 Unité Amélioration, Génétique et Physiologie Forestières, 2163 Avenue de la Pomme de Pin, CS 4001, Ardon, F-45075 Orléans Cedex 2, France.
Alexandre
A
Morel
Caroline
C
Teyssier
Jean-François
JF
Trontin
Kateřina
K
Eliášová
Bedřich
B
Pešek
Martine
M
Beaufour
Domenico
D
Morabito
Nathalie
N
Boizot
Claire
C
Le Metté
Leila
L
Belal-Bessai
Isabelle
I
Reymond
Luc
L
Harvengt
Martine
M
Cadene
Françoise
F
Corbineau
Martin
M
Vágner
Philippe
P
Label
Marie-Anne
MA
Lelu-Walter
D000040:Abscisic Acid / Q000378:metabolism; D006023:Glycoproteins; D028223:Pinus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins; D058439:Plant Somatic Embryogenesis Techniques; D040901:Proteomics; D012639:Seeds / Q000235:genetics*; D059467:Transcriptome; D014867:Water / Q000378:metabolism*
D006023:Glycoproteins; D010940:Plant Proteins; D014867:Water; C058814:germin; D000040:Abscisic Acid