查看更多>>摘要：In grafted plants, rootstock growth and stress resistance are influenced by scion traits, but the underlying mechanism is unclear in apple. In this study, we analyzed seedlings comprising wild-type (WT) or increasedbranching mutant (MB) scions on Malus robusta rootstock on the basis of RNA-seq data, physiological and biochemical indices, and gene expression. Gene functional analysis of RNA-seq data revealed plant-pathogen interaction was the most significantly enriched biological pathway in the axillary buds and roots compared MB with WT. Most genes related to stress responses had up-regulated expression in the MB roots. The leaf water potential, chlorophyll content, and photochemical efficiency were lower in the MB leaves, whereas the water loss rate was higher. The sucrose, glucose, fructose, and sorbitol contents increased significantly in the MB leaves, but decreased in the stems. In the MB roots, there was no change in sucrose and glucose contents, but the fructose and sorbitol contents increased and decreased, respectively. The nitrogen, phosphorus, and potassium contents were higher in the MB roots, while lower nitrogen and phosphorus and higher potassium contents in MB leaves. The abscisic acid, malondialdehyde, and hydrogen peroxide levels increased significantly in the MB seedlings, whereas the antioxidant enzyme activities decreased, especially in the roots and leaves, which was in accordance with the down-regulated expression of the genes related to antioxidant enzyme synthesis. These changes in the MB roots were apparently due to MB scion traits, suggesting that rootstock vitality in grafted apple trees may be affected by the nutrient distribution, hormone level, and antioxidative stress tolerance of the scion.
NSTL
Elsevier