Study : Asparaginase 2 gene expression as a biomarker in response to nitrate ans sucrose during bud outgrowth in Rosa hybrida
Asparaginase 2 gene expression as a biomarker in response to nitrate ans sucrose during bud outgrowth in Rosa hybrida
Axillary bud outgrowth is an essential process of plant branching to set-up its architecture. Nitrogen is implicated in the development of young organs such as secondary axes (axes II) resulting from bud outgrowth. We have previously shown in planta that asparagine concentration increases in the sap and in the tissues during axes II elongation. In vitro, we demonstrated that this amino acid is the sole at its physiological concentration able to evoke an efficient elongation of axes II in the presence of different sugars. To go further, we performed in this work a transcriptomic analysis through RNA sequencing and obtained 848 annotated sequences that are potentially implicated in bud outgrowth in response to nitrate in the presence of sucrose. Among them, the expression of Asparaginase 2 gene takes place during dormancy while, in contrast, Asparagine synthase 2 gene is active during bud outgrowth. So we have established through qRT-PCR the expression level of the main growth regulators related genes in the permissive condition in the presence of asparagine and sucrose. We confirmed using conceptually different experiments that asparagine has a strong involvement in bud outgrowth and demonstrated that the genes implicated in its metabolism could be consider as new biomarkers in the process in rosebush. Overall design: Median nodes cultivated in vitro on sucrose medium supplemented with nitrate were compared to a control without nitrate. 30 nodes per sample were pooled for each sequencing.