Transcriptome Analysis Of The Effect Of Maternal Plant Age On Adventitous Rooting Of Poplar Cuttings

In poplar cuttage propagation,the age effect of cuttings has a significant effect on adventitious roots.Therefore,the study on the molecular mechanism of age effect in adventitious rooting formation of poplar cuttings can provide a new way to solve the problem of the decline of adventitious rooting ability.Previous morphological observation showed that the adventitious rooting rate of 1,2 and 3-year-old cuttings of hybrid triploid ’Beilinxiongzhu 2’ decreased with the increase of the age of the mother plant in the early stage of adventitious rooting formation.In this study,transcriptome analysis was carried out on the uncultivated（CK）and 5-day（D5）cuttings of 1-,2-and 3-year-old hybrid triploid cultivars ’Beilinxiongzhu 2’.Significant differentially expressed genes were screened and enriched by GO and KEGG.Finally,fluorescence quantitative PCR was used to verify the differentially expressed genes.A total of 5058 differentially expressed genes were found,of which 120 were co-expressed differentially in D5₁/CK1,D5₂/CK2 and D5₃/CK3 comparison groups.The results showed that the gene expression pattern of 1-year-old cuttings changed significantly in the early stage of adventitious root formation,while that of 2-year-old and 3-year-old cuttings changed slightly.Before and after adventitious rooting,differentially expressed genes were mainly enriched in the following metabolic pathways:signal transduction,energy metabolism,translation,sugar metabolism,biosynthesis of other secondary metabolites and amino acid metabolism.With the increase of maternal age,phenylpropane substances and oxidative phosphorylation related genes were significantly enriched.The results of this study on the relationship between cuttage age and adventitious root development of poplar will provide important theoretical support for cuttage propagation.