Osmotic stress in roots drives lipoxygenase-dependent plastid remodeling through singlet oxygen production

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: April 22, 2024

Abstract Osmotic stress, caused by the lack of water or high salinity, is a common environmental problem in roots. stress can be reproducibly simulated with application solutions high-molecular-weight and impermeable polyethylene glycol. Different reactive oxygen species such as singlet oxygen, superoxide hydrogen peroxide accompany this stress. Among them, produced byproduct lipoxygenase activity, was shown to associated limiting root growth. To better understand source effect its production followed at cellular level. initiated profound changes plastid morphology vacuole structure. By confocal electron microscopy plastids were accompanied appearance multiple small extraplastidic bodies that also an intense oxygen. A marker protein, CRUMPLED LEAF, indicated these originated from outer membrane. Remarkably type 9 lipoxygenase, LOX5, change distribution uniformly cytoplasmic more clumped together bodies. In addition, oxylipin products increased while 13 lipoxygenases decreased. Inhibition SHAM inhibitor down-regulated lines prevented cells initiating responses leading cell death. contrast, scavenging halted terminal These findings underscore reversible nature osmotic stress-induced changes, emphasizing pivotal roles physiology.

Language: Английский

Autophagosome development and chloroplast segmentation occur synchronously for piecemeal degradation of chloroplasts

eLife, Journal Year: 2023, Volume and Issue: 12

Published: Dec. 19, 2023

Plants distribute many nutrients to chloroplasts during leaf development and maturation. When leaves senesce or experience sugar starvation, the autophagy machinery degrades chloroplast proteins facilitate efficient nutrient reuse. Here, we report on intracellular dynamics of an pathway responsible for piecemeal degradation components. Through live-cell monitoring morphology, observed formation budding structures in sugar-starved leaves. These buds were then released incorporated into vacuolar lumen as autophagic cargo termed a Rubisco-containing body. The did not accumulate mutants core machinery, suggesting that autophagosome creation is required forming buds. Simultaneous tracking morphology revealed isolation membranes autophagosomes interact closely with part surface before Chloroplasts protrude at site associated membranes, which divide synchronously This autophagy-related division does require DYNAMIN-RELATED PROTEIN 5B, constitutes ring proliferation growing An unidentified may thus fragment coordination chloroplast-associated membrane.

Language: Английский