Efficient carbon recycling and modulation of antioxidants involved in elongation of the parasitic plant dodder (Cuscuta spp.) in vitro

• Published in: Plant science (Limerick) 2021-02, Vol.303, p.110770-110770, Article 110770
• Main Authors: Zhang, Yuexia, Zhang, Yushi, Xing, Jiapeng, Li, Yajun, Yang, Yan, Wang, Yubin, Jiang, Linjian, Zhang, Mingcai, Li, Zhaohu
• Format: Article
• Language: English
• Subjects: Antioxidants - metabolism; Carbohydrate Metabolism; Carbon - metabolism; Cuscuta - growth & development; Cuscuta - metabolism; Cuscuta - ultrastructure; Dodder; Growth; Microscopy, Electron, Transmission; Plant Shoots - growth & development; Plant Shoots - metabolism; Plant Shoots - ultrastructure; Proteomics; Reactive Oxygen Species - metabolism; ROS; Sugar starvation
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2020.110770

•Carbohydrates in the basal stems were continuously degraded as the major storage energy for shoot elongation in vitro.•The shoot tips exhibited greater capacity for ROS scavenging compared with the basal stems.•Comparative proteomics revealed the different metabolism patterns in the basal stems and the shoot tips. Dodder is a holoparasitic flowering plant that re-establishes parasitism with the host when broken off from the host. However, how in vitro dodder shoots recycle stored nutrients to maintain growth for reparasitizing hosts is not well characterized. Here, the spatial and temporal distribution characteristics of carbohydrates and reactive oxygen species (ROS) were analysed to explore the mechanism of recycling stored nutrients in dodder shoots in vitro. Our results showed that in vitro dodder shoots grew actively for more than 10 d, while dry mass decreased continuously. During this process, the transcript levels and activities of amylases gradually increased until 2 d and then declined in basal stems, which induced starch degradation at the tissue, cellular and subcellular levels. Additionally, the distribution characteristics of H2O2 and the activities and transcript levels of antioxidant enzymes indicated that shoot tips exhibited more robust ROS-scavenging capacity, and basal stems maintained higher ROS accumulation. Comparative proteomics analysis revealed that starch in basal stems acted as an energy source, and the glycolysis, TCA cycle and pentose phosphate pathway represented the energy supply for shoot tip elongation with time. These results indicated that efficient nutrient recycling and ROS modulation facilitated the parasitism of dodder grown in vitro by promoting shoot elongation growth to reach the host.