Enhanced Autophagic Activity Improved the Root Growth and Nitrogen Utilization Ability of Apple Plants under Nitrogen Starvation

• Main Authors: Liuqing Huo, Zijian Guo, Qi Wang, Li Cheng, Xin Jia, Ping Wang, Xiaoqing Gong, Cuiying Li, Fengwang Ma
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: International Journal of Molecular Sciences
• Subjects: apple; autophagy; <i>MdATG10</i>; nitrogen assimilation; nitrogen starvation
• Online Access: https://www.mdpi.com/1422-0067/22/15/8085
• ISSN: 1661-6596; 1422-0067

Autophagy is a conserved degradation pathway for recycling damaged organelles and aberrant proteins, and its important roles in plant adaptation to nutrient starvation have been generally reported. Previous studies found that overexpression of autophagy-related (ATG) gene <i>MdATG10</i> enhanced the autophagic activity in apple roots and promoted their salt tolerance. The <i>MdATG10</i> expression was induced by nitrogen depletion condition in both leaves and roots of apple plants. This study aimed to investigate the differences in the growth and physiological status between wild type and <i>MdATG10</i>-overexpressing apple plants in response to nitrogen starvation. A hydroponic system containing different nitrogen levels was used. The study found that the reduction in growth and nitrogen concentrations in different tissues caused by nitrogen starvation was relieved by <i>MdATG10</i> overexpression. Further studies demonstrated the increased root growth and the higher nitrogen absorption and assimilation ability of transgenic plants. These characteristics contributed to the increased uptake of limited nitrogen nutrients by transgenic plants, which also reduced the starvation damage to the chloroplasts. Therefore, the <i>MdATG10</i>-overexpressing apple plants could maintain higher photosynthetic ability and possess better growth under nitrogen starvation stress.