How Lipids Contribute to Autophagosome Biogenesis, a Critical Process in Plant Responses to Stresses

Abstract

Throughout their life cycle, plants face a tremendous number of environmental and developmental stresses. To respond to these different constraints, they have developed a set of refined intracellular systems including autophagy. This pathway, highly conserved among eukaryotes, is induced by a wide range of biotic and abiotic stresses upon which it mediates the degradation and recycling of cytoplasmic material. Central to autophagy is the formation of highly specialized double membrane vesicles called autophagosomes which select, engulf, and traffic cargo to the lytic vacuole for degradation. The biogenesis of these structures requires a series of membrane remodeling events during which both the quantity and quality of lipids are critical to sustain autophagy activity. This review highlights our knowledge, and raises current questions, regarding the mechanism of autophagy, and its induction and regulation upon environmental stresses with a particular focus on the fundamental contribution of lipids. How autophagy regulates metabolism and the recycling of resources, including lipids, to promote plant acclimation and resistance to stresses is further discussed.

Crossing paths: recent insights in the interplay between autophagy and intracellular trafficking in plants

“…The identity of intracellular vesicles is defined by both the proteins that decorate them and by the lipids that compose them [66]. Lipid identity has been shown to be consequential in many steps of the autophagy pathway [67]. A noteworthy example of the lipid‐associated implications and crosstalk that may occur between the autophagy pathway and vesicle trafficking is the role of the length of very‐long chain fatty acids in mediating PI3P homeostasis, a crucial lipid for both autophagosome biogenesis and LE/MVB identity [68] (Fig.…”

Vacuolar Processing Enzymes in Plant Programmed Cell Death and Autophagy

“…In animals, the autophagosome is directed to the lysosome, where they fuse, creating an autolysosome. Finally, in both the vacuole and the autolysosome, cargo is degraded by lytic enzymes [ 11 , 79 , 83 ]. Microautophagy ( Figure 1 b) is an autophagy pathway in which autophagosomes are not formed.…”

Cell Death Signaling From Endoplasmic Reticulum Stress: Plant-Specific and Conserved Features

“…Autophagy (meaning "self-eating"), conserved in all eukaryotes, is a cell-sparing process and represents a macromolecule degradation process, in which cells recycle cytoplasmic contents, whole or pieces of organelles through the lysosomes in metazoans, or the vacuole in yeast and plants Wan and Jiang, 2016). Under optimal growth conditions, this process is kept at basal levels but is highly upregulated by a wide variety of biotic and abiotic stresses, such as nutrient starvation, pathogen infection, heat, or drought stress (Liu et al, 2009;Li et al, 2015;Gomez et al, 2021). Autophagy may also be triggered by ER stress through ER stress inducers, such as TM and DTT , leading to engulfment of ER membranes (ER-phagy; Grumati et al, 2018).…”