Unraveling the roles of autophagy in proteome dynamics and energy metabolism in plants under abiotic stress

Abiotic stresses impose major constraints on plant growth and productivity by disrupting cellular homeostasis, energy metabolism, and resource allocation. These challenges are further intensified by climate change, which increases the frequency, duration, and severity of environmental stresses. Because stress adaptation requires extensive metabolic reprogramming, mechanisms that maintain energetic balance and cellular integrity are critical for plant survival. Autophagy, a conserved intracellular recycling pathway, contributes to the degradation and remobilization of cellular constituents, providing substrates for energy production while maintaining organelle and proteome quality. Despite increasing recognition of its importance, the contribution of autophagy to energetic metabolism under prolonged abiotic stress remains incompletely understood. This thesis investigated the role of autophagy in maintaining plant energy homeostasis under two major abiotic constraints, high temperature and phosphate (Pi) starvation, using Arabidopsis thaliana as a model system. In Chapter 1, a comprehensive review synthesized current knowledge on the role of autophagy in plant heat-stress responses, highlighting its functions in thermotolerance, thermomemory, recovery, proteostasis, organelle quality control, and reproductive resilience. In Chapter 2, experimental analyses subsequently demonstrated that autophagy is essential for acclimation to prolonged warming, sustaining thermomorphogenic growth, photosynthetic performance, water conservation, and metabolic coordination. Proteomic and metabolic evidence revealed that autophagy preserves organelle integrity, promotes proteome stability, and prevents maladaptive activation of alternative catabolic pathways during chronic heat exposure. The role of autophagy in nutrient stress was investigated through mitochondrial and whole-plant responses to Pi starvation. In chapter 3, under Pi limitation, autophagy-deficient mutants exhibited accelerated depletion of intracellular Pi pools, impaired respiratory acclimation, and extensive remodeling of the mitochondrial proteome, indicating a critical role for autophagy in maintaining mitochondrial energetic competence. In chapter 4, at the whole-plant level, autophagy-deficient mutants showed disrupted root-to-shoot Pi redistribution, promoted Pi retention in roots and depletion in shoots, altered biomass allocation, and induced tissue-specific metabolic reprogramming. Proteomic analyses further revealed that autophagy regulates the transition from plastidial carbon assimilation to glycolytic and respiratory energy production during prolonged Pi deprivation. Collectively, the results presented in this thesis establish autophagy as a regulator of energetic homeostasis under abiotic stress. Rather than functioning solely as a degradative recycling mechanism, autophagy emerges as a multi-scale homeostatic system that integrates nutrient recycling, organelle maintenance, proteome remodeling, and metabolic flexibility to sustain plant acclimation under prolonged environmental stress. These findings advance our understanding of the physiological and molecular mechanisms underlying stress resilience and identify autophagy as a promising target for the development of crops better adapted to future climatic and nutritional challenges. Keywords: autophagy; energetic metabolism; proteomics; phosphate limitation; prolonged warming; Arabidopsis thaliana.

Grantor dc:publisher

Universidade Federal de Viçosa

Year dc:date.issued

2026

Author dc:creator

• Nogueira, Bianca Bueno

Advisor dc:contributor.advisor

• Araújo, Wagner Luiz

Contributors dc:contributor

• Barros, Jessica Aline Sousa

• Arabidopsis thaliana
• Autofagia
• Metabolismo energético
• Proteínas
• Estresse (Fisiologia)
• Arabidopsis thaliana - Fisiologia - Efeitos do calor

Statement dc:rights

• Acesso Aberto

Language dc:language.iso

eng

DOI

https://doi.org/10.47328/ufvbbt.2026.365

OAI identifier oai:identifier

oai:locus.ufv.br:123456789/35585